Tag: fertilizers

A farmer in the Ara district, in India's Bihar state, applies NPK fertilizer, composed primarily of nitrogen, phosphorus and potassium. (Photo: Dakshinamurthy Vedachalam/CIMMYT)

Biological nitrogen fixation and prospects for ecological intensification in cereal-based cropping systems

Written by Sarah McLaughlin on August 23, 2022. Posted in Publications.

Among the inputs needed for a healthy soil, nitrogen is unique because it originates from the atmosphere. How it moves from the air to the ground is governed in part by a process called biological nitrogen fixation (BNF), which is catalyzed by specific types of bacteria.

Nitrogen supply is frequently the second most limiting factor after water availability constraining crop growth and so there is great farmer demand for accessible sources of nitrogen, such as synthetic nitrogen in fertilizer. This increasing demand has continued as new cereal varieties with higher genetic yield potential are being released in efforts to feed the world’s growing population.

Currently, the primary source for nitrogen is synthetic, delivered through fertilizers. Synthetic nitrogen revolutionized cereal crop (e.g., wheat, maize, and rice) production by enhancing growth and grain yield as it eliminated the need to specifically allocate land for soil fertility rejuvenation during crop rotation. However, synthetic nitrogen is not very efficient, often causing excess application, which leads to deleterious forms, including ammonia, nitrate, and nitrogen oxides escaping into the surrounding ecosystem, resulting in a myriad of negative impacts on the environment and human health. Nitrogen loss from fertilizer is responsible for a nearly 20% increase in atmospheric nitrous oxide since the industrial revolution. Notably, more nitrogen from human activities, including agriculture, has been released to the environment than carbon dioxide during recent decades, leading climate scientists to consider the possibility that nitrogen might replace carbon as a prime driver of climate change.

New research co-authored by International Maize and Wheat Improvement Center (CIMMYT) scientists, published in Field Crops Research, posits that facilitating natural methods of gathering useable nitrogen in BNF can reduce the amount of synthetic nitrogen being used in global agriculture.

As agricultural systems become more intensive regarding inputs and outputs, synthetic nitrogen has become increasingly crucial, but there are still extensive areas in the world that cannot achieve food and nutrition security because of a lack of nitrogen.

“This, together with increasing and changing dietary demands, shows that the future demand for nitrogen will substantially grow to meet the anticipated population of 9.7 billion people by the middle of the century,” said J.K. Ladha, adjunct professor in the Department of Plant Sciences at University of California, Davis, and lead author of the study.

Before the synthetic nitrogen, the primary source of agricultural nitrogen was gathered through BNF as bacteria living underground that convert atmospheric nitrogen into nitrogen that can be utilized by crops. Therefore, legumes are often employed as a cover crop in rotating fields to replenish nitrogen stocks; their root systems are hospitable for these nitrogen producing bacteria to thrive.

“There are ways in which BNF could be a core component of efforts to build more sustainable and regenerative agroecosystems to meet nitrogen demand with lower environmental footprints,” said Timothy Krupnik, Senior System Agronomist at CIMMYT in Dhaka, Bangladesh.

Plant scientists have often hypothesized that the ultimate solution for solving the ever-growing nitrogen supply challenge is to confer cereals like wheat, maize, rice, with their own capacity for BNF. Recent breakthroughs in the genomics of BNF, as well as improvements in the understanding how legumes and nitrogen bacteria interact, have opened new avenues to tackle this problem much more systematically.

“Enabling cereal crops to capture their own nitrogen is a long-standing goal of plant biologists and is referred to as the holy grail of BNF research,” said P.M. Reddy, Senior Fellow at The Energy Research Institute, New Delhi. “The theory is that if cereal crops can assemble their own BNF system, the crop’s internal nitrogen supply and demand can be tightly regulated and synchronized.”

The study examined four methods currently being employed to establish systems within cereal crops to capture and use their own nitrogen, each with their advantages and limitations. One promising method involves identifying critical plant genes that perceive and transmit nitrogen-inducing signals in legumes. Integrating these signal genes into cereal crops might allow them to construct their own systems for BNF.

“Our research highlights how BNF will need to be a core component of efforts to build more sustainable agroecosystems,” said Mark Peoples, Honorary Fellow at The Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, Australia. “To be both productive and sustainable, future cereal cropping systems will need to better incorporate and leverage natural processes like BNF to mitigate the corrosive environmental effects of excess nitrogen leaking into our ecosystems.”

Besides the efforts to bring BNF to cereals, there are basic agronomic management tools that can shift focus from synthetic to BNF nitrogen.

“Encouraging more frequent use of legumes in crop rotation will increase diversification and the flow of key ecosystem services, and would also assist the long-term sustainability of cereal-based farming systems,” said Krupnik.

Read the study: Biological nitrogen fixation and prospects for ecological intensification in cereal-based cropping systems

Cover photo: A farmer in the Ara district, in India’s Bihar state, applies NPK fertilizer, composed primarily of nitrogen, phosphorus and potassium. (Photo: Dakshinamurthy Vedachalam/CIMMYT)

BNI-enhanced wheat research wins 2021 Cozzarelli Prize

Written by Rodrigo Ordóñez on April 1, 2022. Posted in News.

The paper “Enlisting wild grass genes to combat nitrification in wheat farming: A nature-based solution” received the 2021 Cozzarelli Prize, which recognizes outstanding articles published in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS). The paper was published as a joint research collaboration of Japan International Research Center for Agricultural Sciences (JIRCAS), the International Maize and Wheat Improvement Center (CIMMYT), the University of the Basque Country (UPV/EHU) and Nihon University.

The study identifies of a chromosomal region that regulates the biological nitrification inhibition (BNI) ability of wheat grass (Leymus racemosus), a wild relative of wheat. It also outlines the development of the world’s first BNI-enhanced wheat, through intergeneric crossing with a high-yielding wheat cultivar.

This research result is expected to contribute to the prevention of nitrogen pollution that leads to water pollution and greenhouse gas emissions, reducing the use of nitrogen fertilizer while maintaining productivity.

Best of the year

PNAS is one of the most cited scientific journals in the world, publishing more than 3,000 papers per year on all aspects of science. A total of 3,476 papers were published in 2021, covering six fields: Physical and Mathematical Sciences, Biological Sciences, Engineering and Applied Sciences, Biomedical Sciences, Behavioral and Social Sciences, and Applied Biological, Agricultural and Environmental Sciences.

The Cozzarelli Prize was established in 2005 as the PNAS Paper of the Year Prize and renamed in 2007 to honor late editor-in-chief Nicholas R. Cozzarelli. It is awarded yearly by the journal’s Editorial Board to one paper from each field reflecting scientific excellence and originality. The BNI research paper received the award in the category of Applied Biological, Agricultural, and Environmental Sciences.

The awards ceremony will be held online on May 1, 2022, and a video introducing the results of this research will be available.

Recently, lead researcher Guntur V. Subbarao presented this research on a talk at Princeton University’s Center for Policy Research on Energy and the Environment: “Low-nitrifying agricultural systems are critical for the next Green Revolution.”

Fruitful collaboration

CIMMYT has collaborated with JIRCAS on BNI-enhanced wheat research since 2009, with funding from Japan’s Ministry of Agriculture, Forestry and Fisheries. CIMMYT is one of the founding members of the BNI Consortium, established in 2015.

The CGIAR Research Programs on Wheat (WHEAT) and Maize (MAIZE) co-funded BNI research since 2014 and 2019 respectively, until their conclusion at the end of 2021.

BNI research has been positioned in the “Measures for achievement of Decarbonization and Resilience with Innovation (MeaDRI)” strategy of Japan’s Ministry of Agriculture, Forestry and Fisheries, and was also selected as one of the ministry’s “Top 10 agricultural technology news for 2021.”

Read the full article:
Enlisting wild grass genes to combat nitrification in wheat farming: A nature-based solution

A farmer shows maize growing in his field, in one of the communities in northern Nigeria which participated in the study. (Photo: Oyakhilomen Oyinbo)

Understanding decision support

Written by Rodrigo Ordóñez on September 9, 2021. Posted in Features.

Given the very heterogeneous conditions in smallholder agriculture in sub-Saharan Africa, there is a growing policy interest in site-specific extension advice and the use of related digital tools. However, empirical ex ante studies on the design of this type of tools are scant and little is known about their impact on site-specific extension advice.

In partnership with Oyakhilomen Oyinbo and colleagues at KU Leuven, scientists at the International Maize and Wheat Improvement Center (CIMMYT) have carried out research to clarify user preferences for tailored nutrient management advice and decision-support tools. The studies also evaluated the impact of targeted fertilizer recommendations enabled by such tools.

Understanding farmers’ adoption

A better understanding of farmers’ and extension agents’ preferences may help to optimize the design of digital decision-support tools.

Oyinbo and co-authors conducted a study among 792 farming households in northern Nigeria, to examine farmers’ preferences for maize intensification in the context of site-specific extension advice using digital tools.

Overall, farmers were favorably disposed to switch from general fertilizer use recommendations to targeted nutrient management recommendations for maize intensification enabled by decision-support tools. This lends credence to the inclusion of digital tools in agricultural extension. The study also showed that farmers have heterogeneous preferences for targeted fertilizer recommendations, depending on their resources, sensitivity to risk and access to services.

The authors identified two groups of farmers with different preference patterns: a first group described as “strong potential adopters of site-specific extension recommendations for more intensified maize production” and a second group as “weak potential adopters.” While the two groups of farmers are willing to accept some yield variability for a higher average yield, the trade-off is on average larger for the first group, who have more resources and are less sensitive to risk.

The author recommended that decision-support tools include information on the riskiness of expected investment returns and flexibility in switching between low- and high-risk recommendations. This design improvement will help farmers to make better informed decisions.

Community leaders talk to researchers in one of the villages in norther Nigeria which took part in the study. (Photo: Oyakhilomen Oyinbo)

Members of the survey team participate in a training session at Bayero University Kano, Nigeria. (Photo: Oyakhilomen Oyinbo)

One of the sites of nutrient omission trials, used during the development phase of the Nutrient Expert tool in Nigeria. (Photo: Oyakhilomen Oyinbo)

Extension agents go digital

While farmers are the ultimate recipients of extension advice, extension agents are most often the actual users of decision-support tools. In another study, the authors provided ex ante insights on the potential uptake of nutrient management decision-support tools and the specific design features that are more (or less) appealing to extension agents in the maize belt of northern Nigeria.

Using data from a discrete choice experiment, the study showed that extension agents were generally willing to accept the use of digital decision-support tools for site‐specific fertilizer recommendations. While extension agents in the sample preferred tools with a more user‐friendly interface that required less time to generate an output, the authors also found substantial preference heterogeneity for other design features. Some extension agents cared more about the outputs, such as information accuracy and level of detail, while others prioritized practical features such as the tool’s platform, language or interface.

According to the authors, accounting for such variety of preferences into the design of decision-support tools may facilitate their adoption by extension agents and, in turn, enhance their impact in farmars’ agricultural production decisions.

Interface of the Nutrient Expert mobile app, locally calibrated for maize farmers in Nigeria.

Impact of digital tools

Traditional extension systems in sub-Saharan African countries, including Nigeria, often provide general fertilizer use recommendations which do not account for the substantial variation in production conditions. Such blanket recommendations are typically accompanied by point estimates of expected agronomic responses and associated economic returns, but they do not provide any information on the variability of the expected returns associated with output price risk.

Policymakers need a better understanding of how new digital agronomy tools for tailored recommendations affect the performance of smallholder farms in developing countries.

To contribute to the nascent empirical literature on this topic, Oyinbo and colleagues evaluated the impact of a nutrient management decision-support tool for maize – Nutrient Expert — on fertilizer use, management practices, yields and net revenues. The authors also evaluated the impacts of providing information about variability in expected investment returns.

To provide rigorous evidence, the authors conducted a three-year randomized controlled trial among 792 maize-producing households in northern Nigeria. The trial included two treatment groups who are exposed to site-specific fertilizer recommendations through decision-support tools — one with and another one without additional information on variability in expected returns — and a control group who received general fertilizer use recommendations.

Overall, the use of nutrient management decision-support tools resulted in greater fertilizer investments and better grain yields compared with controls. Maize grain yield increased by 19% and net revenue increased by 14% after two years of the interventions. Fertilizer investments only increased significantly among the farmers who received additional information on the variability in expected investment returns.

The findings suggest including site-specific decision support tools into extension programming and related policy interventions has potential benefits on maize yields and food security, particularly when such tools also supply information on the distribution of expected returns to given investment recommendations.

The research-for-development community has tried different approaches to optimize fertilizer recommendations. In Nigeria, there are several tools available to generate location-specific fertilizer recommendations, including Nutrient Expert. As part of the Taking Maize Agronomy to Scale in Africa (TAMASA) project, CIMMYT has been working on locally calibrated versions of this tool for maize farmers in Ethiopia, Nigeria and Tanzania. The development was led by a project team incorporating scientists from the African Plant Nutrition Institute (APNI), CIMMYT and local development partners in each country.

Next steps

Some studies have shown that dis-adoption of seemingly profitable technologies — such as fertilizer in sub-Saharan Africa — is quite common, especially when initial returns fall short of expectations or net utility is negative, producing a disappointment effect.

In the context of emerging digital decision-support tools for well-targeted fertilizer use recommendations, it remains unclear whether farmers’ initial input use responses and the associated economic returns affect their subsequent responses — and whether the disappointment effect can be attenuated through provision of information about uncertainty in expected returns.

Using our three-year randomized controlled trial and the associated panel dataset, researchers are now working on documenting the third-year responses of farmers to site-specific agronomic advice conditional on the second-year responses. Specifically, they seek to better document whether providing farmers with information about seasonal variability in expected investment returns can reduce possible disappointment effects associated with their initial uptake of site-specific agronomic advice and, in a way, limit dis-adoption of fertilizer.

Cover photo: A farmer shows maize growing in his field, in one of the communities in northern Nigeria where research took place. (Photo: Oyakhilomen Oyinbo)

Nitrogen-efficient wheats provide more food with fewer greenhouse gas emissions

Written by Bea Ciordia on September 8, 2021. Posted in In the media.

An international collaboration has discovered a biological nitrification inhibition (BNI) trait that, when transferred to growing wheat varieties, can reduce the use of fertilizers for wheat crops and increase yields.

Nitrogen-efficient wheats can provide more food with fewer greenhouse gas emissions, new study shows

Written by Rodrigo Ordóñez on September 1, 2021. Posted in Press releases.

An international collaboration has discovered and transferred to elite wheat varieties a wild-grass chromosome segment that causes roots to secrete natural inhibitors of nitrification, offering a way to dial back on heavy fertilizer use for wheat and to reduce the crop’s nitrogen leakage into waterways and air, while maintaining or raising its productivity and grain quality, says a new report in the Proceedings of the National Academy of Sciences of the United States of America.

Growing wheat varieties endowed with the biological nitrification inhibition (BNI) trait could increase yields in both well-fertilized and nitrogen-poor soils, according to G.V. Subbarao, researcher at the Japan International Research Center for Agricultural Sciences (JIRCAS) and first author of the new report.

“Use of wheat varieties that feature BNI opens the possibility for a more balanced and productive mix of nitrogen nutrients for wheat fields, which are currently dominated by highly-reactive nitrogen compounds that derive in large part from synthetic fertilizers and can harm the environment,” Subbarao said.

The most widely grown food crop on the planet, wheat is consumed by over 2.5 billion people in 89 countries. Nearly a fifth of the world’s nitrogen-based fertilizer is deployed each year to grow wheat but, similar to other major cereals, vegetables, and fruits, the crop takes up less than half of the nitrogen applied.

Much of the remainder is either washed away, contaminating ground waters with nitrate and contributing to algae blooms in lakes and seas, or released into the air, often as nitrous oxide, a greenhouse gas 300 times more potent than carbon dioxide.

The study team first homed in on the chromosome region associated with the strong BNI capacity in the perennial grass species Leymus racemosus and moved it from the grass, using “wide crossing” techniques, into the cultivar Chinese Spring, a wheat landrace often used in genetic studies. From there, they transferred the BNI chromosome sequence into several elite, high-yielding wheat varieties, leading to a near doubling of their BNI capacity, as measured through lab analyses of soil near their roots.

The new wheats — elite varieties from the International Maize and Wheat Improvement Center (CIMMYT) into which the BNI trait was cross-bred — greatly reduced the action of soil microbes that usually convert fertilizer and organic nitrogen substances into ecologically-harmful compounds such as nitrous oxide gas, according to Hannes Karwat, a CIMMYT post-doctoral fellow and study co-author.

“The altered soil nitrogen cycle was even reflected in the plants’ metabolism,” Karwat said, “resulting in several responses indicative of a more balanced nitrogen uptake in the plants.”

The scientists involved said BNI-converted wheats in this study also showed greater overall biomass and grain yield, with no negative effects on grain protein levels or breadmaking quality.

“This points the way for farmers to feed future wheat consumers using lower fertilizer dosages and lowering nitrous oxide emissions,” said Masahiro Kishii, a CIMMYT wheat cytogeneticist who contributed to the research. “If we can find new BNI sources, we can develop a second generation of elite wheat varieties that require even less fertilizer and that better deter nitrous oxide emissions.”

A recent PNAS paper by Subbarao and Princeton University scientist Timothy D. Searchinger mentions BNI as a technology that can help foster soils featuring a more even mix of nitrogen sources, including more of the less-chemically-reactive compound ammonium, a condition that can raise crop yields and reduce nitrous oxide emissions.

CIMMYT researcher Masahiro Kishii examines wheat plants in a greenhouse. (Photo: CIMMYT)

Scale out to slow global warming?

The present study comes just as the Intergovernmental Panel on Climate Change (IPCC) has released its Sixth Assessment Report, which among other things states that “… limiting human-induced global warming … requires limiting cumulative CO₂ emissions … along with strong reductions in other greenhouse gas emissions.”

Globally, 30% of greenhouse gas emissions come from agriculture. BNI-enabled wheat cultivars can play an important role to reduce that footprint. Wheat-growing nations that have committed to the Paris Climate Accord, whose provisions include reducing greenhouse gas emissions 30% by 2050, could be early adopters of the BNI technology, together with China and India, the world’s top two wheat producers, according to Subbarao.

“This work has demonstrated the feasibility of introducing BNI-controlling chromosome segments into modern wheats, without disrupting their yields or quality,” said Subbarao. “To realize the technology’s full potential, we need to transfer the BNI feature into many elite varieties adapted to diverse wheat growing areas and to assess their yield in many farm settings and with varying levels of soil pH, fertilization and water use.”

A project to establish nitrogen-efficient wheat production systems in the Indo-Gangetic Plains using BNI has recently been approved by Japan and is under way, with the collaboration of JIRCAS, the Indian Council of Agricultural Research (ICAR), and the Borlaug Institute of South Asia (BISA). Under the project, BNI-converted wheat lines developed from JIRCAS-CIMMYT partnerships will be tested in India and the BNI trait transferred to popular national wheat varieties.

“The BNI-technology is also featured in Green Technology, a Japanese government policy document for moving towards a zero-carbon economy,” said Osamu Koyama, President of JIRCAS, which has also posted a note about the new PNAS study. JIRCAS and CGIAR BNI research is co-funded by the Ministry of Agriculture, Forestry and Fisheries of Japan.

“Adaptation and mitigation solutions such as BNI, which help lessen the footprint of food production systems, will play a large role in CGIAR research-for-development, as part of One CGIAR Initiatives starting in 2022,” said Bram Govaerts, CIMMYT Director General.

RELATED RESEARCH PUBLICATIONS:

Enlisting wild grass genes to combat nitrification in wheat farming: A nature-based solution

INTERVIEW OPPORTUNITIES:

Hannes Karwat – Postdoctoral Fellow, Nitrogen Use Efficiency, International Maize and Wheat Improvement Center (CIMMYT)

Masahiro Kishii – Wheat Cytogenetics, Wide Crossing, International Maize and Wheat Improvement Center (CIMMYT)

Victor Kommerell – Program Manager, CGIAR Research Program Wheat (WHEAT)

FOR MORE INFORMATION, OR TO ARRANGE INTERVIEWS, CONTACT THE MEDIA TEAM:

Rodrigo Ordóñez, Communications Manager, CIMMYT. r.ordonez@cgiar.org, +52 (55) 5804 2004 ext. 1167.

Mapping the way to lower nitrous oxide emissions

Written by Steven M on May 26, 2021. Posted in Features.

Like many issues besetting contemporary agri-food systems, the question of nitrogen use appears to yield contradictory problems and solutions depending on where you look. Many parts of the globe are experiencing the environmental consequences of excessive and inefficient use of nitrogen fertilizers. Elsewhere nitrogen-poor soils are a hindrance to agricultural productivity.

Addressing these seemingly contradictory issues means ensuring that nitrogen is applied with maximum efficiency across the world’s croplands. Farmers should be applying as much nitrogen as can be taken up by their crops in any given agroecology. Apply more, and the excess nitrogen leads to nitrous oxide (N₂O) emissions — a potent greenhouse gas (GHG) — and other environmental degradation. Apply less, and agricultural potential goes unmet. Given the twin challenges of global climate change and the projected need to increase global food production over 70% by 2050, neither scenario is desirable.

Maize and wheat agri-food systems are at the heart of this dilemma. These staple crops are critical to ensuring the food security of a growing population. They also account for around 35% of global nitrogen fertilizer usage. Tackling the problem first requires an accurate accounting of global N₂0 emissions from maize and wheat fields, followed by quantification of mitigation potential disaggregated by region. This is the task undertaken by a recent study published in Science of the Total Environment and co-authored by a team of researchers including scientists at the International Maize and Wheat Improvement Center (CIMMYT) and the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS).

“Spatially explicit quantification of N₂O emission and mitigation potential helps identify emission hotspots and priority areas for mitigation action through better nitrogen management consistent with location-specific production and environmental goals,” says Tek Sapkota, CIMMYT’s climate scientist and review editor of the Intergovernmental Panel on Climate Change (IPCC)’s sixth assessment report.

A map shows global hotspots for nitrogen emissions linked to maize and wheat production. (Graphic: Tesfaye et al./CIMMYT)

A model approach

Researchers compared N₂0 emissions estimates produced using four statistical models (Tropical N2O model, CCAF-MOT, IPCC Tier-1 and IPCC Tier-11). They also compared the models’ estimates against actual emissions as recorded at 777 globally distributed points. While all four models performed relatively well vis-à-vis the empirical measurements, the IPCC Tier-II estimates showed a better relationship to the measured data across both maize and wheat fields and low- and high-emissions scenarios.

Researchers found that, for both maize and wheat, emissions were highest in East and South Asia, as well as parts of Europe and North America. For maize, parts of South America also appeared to be emissions hotspots. In Asia, China, India, Indonesia and the Philippines were major emitters for both crops. Researchers also observed that China, along with Egypt, Pakistan and northern India have the highest excess nitrogen application (i.e., nitrogen in excess of what can be productively taken up by crops).

Trimming the excess

Specifically identifying hotspots of excess nitrogen application is important, as they represent promising areas to target for emissions reductions. For a given region, the volume of emissions may be a factor simply of large areas under maize or wheat cultivation coupled with of high levels of nitrogen usage. However, farmers in such regions may be not have much room to reduce nitrogen application without affecting yield. And reducing the area under cultivation may not be desirable or viable. Where the rate of excess nitrogen application is high, however, reducing the rate of application and increasing the efficiency of nitrogen use is a win-win.

A farmer in Ethiopia prepares to spread UREA fertilizer by hand in his field after the sowing of wheat. (Photo: CIMMYT)

The researchers estimate that a nitrous oxide emission reduction potential of 25-75% can be achieved through various management practices, such as the 4Rs, which stand for the right source, right timing, right placement and right application rate. Not only would such a reduction drastically reduce N₂O emissions and lessen other environmental impacts of maize and wheat production, it would represent a significant cost savings to farmers. Improved efficiency in nitrogen application can also have positive effects on crop yield.

“Promoting integrated nitrogen management approaches through the right policies, institutional supports and good extension systems is essential to improving the use efficiency of nitrogen in order to meet food security, climate action and other sustainable development goals,” says Sapkota.

Kindie Tesfaye, a CIMMYT scientist and one of the authors of the paper, adds, “The policy importance of the study is that the estimated mitigation potentials from global maize and wheat fields are useful for hotspot countries to target fertilizer and crop management as one of the mitigation options in their Nationally Determined Contributions (NDCs) to the United Nations Framework Convention on Climate Change (UNFCCC).”

Smallholder farmer Sita Kumari holds fertilizer in her hands. (Photo: C. de Bode/CGIAR)

On-farm nitrogen management practices have global reverberations

Written by Rodrigo Ordóñez on April 9, 2021. Posted in Press releases.

An international team of scientists has strengthened our understanding of how better fertilizer management could help minimize nitrous oxide (N₂O) emissions while still achieving high crop yields in the new publication: Meta-analysis of yield and nitrous oxide outcomes for nitrogen management in agriculture. This research was conducted through a meta-analysis, where the results of multiple scientific studies were statistically combined.

To meet the world’s growing demand for food, farmers need fertile soil. Nitrogen, an essential element in plant fertilizer, can have extremely deleterious effects on the environment when not managed effectively. Numerous studies have confirmed that improving nitrogen use in agriculture is key to securing a food secure future and environmental sustainability.

“Society needs nuanced strategies based upon tailored nutrient management approaches that keep nitrogen balances within safe limits,” said Tai M Maaz, researcher at University of Hawaii at Manoa and lead author of the study.

When farmers apply nitrogen fertilizer to their crop, typically only 30-40% of it is taken up by the plant and the rest is lost the the environment. One byproduct is nitrous oxide (N₂O), one of the most potent greenhouse gases in the atmosphere. Global agriculture is a major contributor of greenhouse gas emissions, especially those derived from nitrous oxide emissions.

Although farmers are now commonly told to practice fertilizer rate reduction, or simply put, to apply less fertilizer, there are cases where that strategy is either not possible or not advisable.

Alternative predictors of emissions

The study found that output indicators such as partial nitrogen balance (PNB), an indicator for the amount of nitrogen prone to loss, and partial factor productivity (PFP), a measure of input-use efficiency, predicted nitrous oxide emissions as well as or better than the application rate alone. This means that in some cases, where nitrogen rate reduction is not possible, nitrous oxide emission can still be reduced by increasing yield through implementation of improved fertilizer management practices, such as the “4Rs:” right source, right timing, right placement and right application rate.

Tek B Sapkota, climate scientist at the International Maize and Wheat Improvement Center (CIMMYT) and co-author of the study, emphasized that “rate reduction is still important in the cropping systems where the current level of nitrogen application is excessively high. But, when comparing the systems at the same nitrogen application rates, nitrous oxide emission can be reduced by increasing yield.”

“The 4R nutrient management practices must be tailored to specific regions to help close yield gaps and maintain environmental sustainability: the win-win scenario. The future will require public and private institutions working together to disseminate such nutrient management information for specific cropping systems in specific geographies,” said Sapkota, who is also a review editor of the Intergovernmental Panel on Climate Change (IPCC) sixth assessment report.

The article was a collaborative effort from the International Maize and Wheat Improvement Center (CIMMYT), the University of Hawaii, the Environmental Defense Fund, Plant Nutrition Canada and the African Plant Nutrition Institute. It was funded by the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS).

Read the full study:
Meta-analysis of yield and nitrous oxide outcomes for nitrogen management in agriculture

FOR MORE INFORMATION, OR TO ARRANGE INTERVIEWS, CONTACT:

Marcia MacNeil, Communications Officer, CGIAR Research Program on Wheat, CIMMYT. m.macneil@cgiar.org

About CIMMYT

The International Maize and Wheat Improvement Center (CIMMYT) is the global leader in publicly-funded maize and wheat research and related farming systems. Headquartered near Mexico City, CIMMYT works with hundreds of partners throughout the developing world to sustainably increase the productivity of maize and wheat cropping systems, thus improving global food security and reducing poverty. CIMMYT is a member of the CGIAR System and leads the CGIAR Research Programs on Maize and Wheat and the Excellence in Breeding Platform. The Center receives support from national governments, foundations, development banks and other public and private agencies. For more information, visit staging.cimmyt.org

Nepal launches digital soil map

Written by Rodrigo Ordóñez on April 7, 2021. Posted in Features.

A new digital soil map for Nepal provides access to location-specific information on soil properties for any province, district, municipality or a particular area of interest. The interactive map provides information that will be useful to make new crop- and site-specific fertilizer recommendations for the country.

Produced by the International Maize and Wheat Improvement Center (CIMMYT), in collaboration with Nepal Agricultural Research Council’s (NARC) National Soil Science Research Center (NSSRC), this is the first publicly available soil map in South Asia that covers the entire country.

The Prime Minister of Nepal, K.P. Sharma Oli, officially launched the digital soil map at an event on February 24, 2021. Oli highlighted the benefits the map would bring to support soil fertility management in the digital era in Nepal. He emphasized its sustainability and intended use, mainly by farmers.

CIMMYT and NSSRC made a live demonstration of the digital soil map. They also developed and distributed an informative booklet that gives an overview of the map’s major features, operation guidelines, benefits, management and long-term plans.

The launch event was led by the Ministry of Agriculture and Livestock Development and organized in coordination with NARC, as part of the Nepal Seed and Fertilizer (NSAF) project, implemented by CIMMYT. More than 200 people participated in the event, including government officials, policymakers, scientists, professors, development partner representatives, private sector partners and journalists. The event was also livestreamed.

Better decisions

Immediately after the launch of the digital soil map, its CPU usage grew up to 94%. Two days after the launch, 64 new accounts had been created, who downloaded different soil properties data in raster format for use in maps and models.

The new online resource was prepared using soil information from 23,273 soil samples collected from the National Land Use Project, Central Agricultural Laboratory and Nepal Agricultural Research Council. The samples were collected from 56 districts covering seven provinces. These soil properties were combined with environmental covariates (soil forming factors) derived from satellite data and spatial predictions of soil properties were generated using advanced machine learning tools and methods.

The platform is hosted and managed by NARC, who will update the database periodically to ensure its effective management, accuracy and use by local government and relevant stakeholders. The first version of the map was finalized and validated through a workshop organized by NSSRC among different stakeholders, including retired soil scientists and university professors.

Ivan Ortiz-Monasterio, principal scientist at CIMMYT, shared his remarks in a video message. (Photo: Shashish Maharjan/CIMMYT)

“The ministry can use the map to make more efficient management decisions on import, distribution and recommendation of appropriate fertilizer types, including blended fertilizers. The same information will also support provincial governments to select suitable crops and design extension programs for improving soil health,” said Padma Kumari Aryal, Minister of Agriculture and Livestock Development, who chaired the event. “The private sector can utilize the acquired soil information to build interactive and user-friendly mobile apps that can provide soil properties and fertilizer-related information to farmers as part of commercial agri-advisory extension services,” she said.

“These soil maps will not only help to increase crop yields, but also the nutritional value of these crops, which in return will help solve problems of public health such as zinc deficiency in Nepal’s population,” explained Ivan Ortiz-Monasterio, principal scientist at CIMMYT, in a video message.

Yogendra Kumar Karki, secretary of the Ministry of Agriculture and Livestock Development, presented the program objectives and Deepak Bhandari, executive director of NARC, talked about the implementation of the map and its sustainability. Special remarks were also delivered by USAID Nepal’s mission director, the secretary of Livestock, scientists and professors from Tribhuwan University, the International Fertilizer Development Center (IFDC) and the International Centre for Integrated Mountain Development (ICIMOD).

K.P. Sharma Oli (left), Prime Minister of Nepal, and Padma Kumari Aryal, Minister of Agriculture and Livestock Development, launch the digital soil map. (Photo: Shashish Maharjan/CIMMYT)

Benefits of digital soil mapping

Soil properties affect crop yield and production. In Nepal, access to soil testing facilities is rather scarce, making it difficult for farmers to know the fertilizer requirement of their land. The absence of a well-developed soil information system and soil fertility maps has been lacking for decades, leading to inadequate strategies for soil fertility and fertilizer management to improve crop productivity. Similarly, existing blanket-type fertilizer recommendations lead to imbalanced application of plant nutrients and fertilizers by farmers, which also negatively affects crop productivity and soil health.

This is where digital soil mapping comes in handy. It allows users to identify a domain with similar soil properties and soil fertility status. The digital platform provides access to domain-specific information on soil properties including soil texture, soil pH, organic matter, nitrogen, available phosphorus and potassium, and micronutrients such as zinc and boron across Nepal’s arable land.

Farmers and extension agents will be able to estimate the total amount of fertilizer required for a particular domain or season. As a decision-support tool, policy makers and provincial government can design and implement programs for improving soil fertility and increasing crop productivity. The map also allows users to identify areas with deficient plant nutrients and provide site-specific fertilizer formulations; for example, determining the right type of blended fertilizers required for balanced fertilization programs. Academics can also obtain periodic updates from these soil maps and use it as a resource while teaching their students.

As digital soil mapping advances, NSSRC will work towards institutionalizing the platform, building awareness at the province and local levels, validating the map, and establishing a national soil information system for the country.

Nepal’s digital soil map is readily accessible on the NSSRC web portal:
https://soil.narc.gov.np/soil/soilmap/

Crop nutrient management using digital tool improves yield, reduces greenhouse gas emissions: Study

Written by Bea Ciordia on March 5, 2021. Posted in In the media.

The use of field-specific fertiliser in the Indo-Gangetic Plains (IGP) can increase grain yield, reduce greenhouse gas emissions compared to traditional farmer fertilization practices (FFP), and lead to reduced costs and increased incomes for farmers.

These were the findings of a study conducted between 2013 and 2017 by the International Maize and Wheat Improvement Centre (CIMMYT) and published in Nature Scientific Report in January 2021.

Breaking Ground: Dyutiman Choudhary builds strong agribusinesses for sustainable economic growth

Written by Rodrigo Ordóñez on February 24, 2021. Posted in Features.

Agricultural market systems play a pivotal role in food security, livelihood development and economic growth. However, the agricultural sector in Nepal is constrained by a lack of spatially-explicit technologies and practices related to improved seed and fertilizer. Embracing these challenges, Dyutiman Choudhary, a scientist in market development with the International Maize and Wheat Improvement Center (CIMMYT), works to strengthen the seed and fertilizer market systems and value chains, with the ultimate goal to ensure demand-driven, inclusive and market-oriented cereal production.

Nepal’s agricultural sector is dominated by smallholder farmers. As farming is mostly semi-commercial and subsistence in nature, many smallholder farmers are isolated from markets and lack knowledge about the latest farming technologies and inputs. They are unable to upgrade their farms to increase productivity for generating marketable surplus to make profitable income. Agribusiness entities in Nepal — such as seed companies, agrodealers and importers — face market development challenges and lack the commercial and business orientation to develop and deliver new technologies to farmers. Output market linkages are weak and loosely integrated, leading to poor coordination, weak information flow and lower return to actors.

This is where Choudhary’s expertise in agribusiness management fits in to make a difference.

Born and raised in Shillong, a hill station in northeastern India with a distinctive charm, he was enrolled as an engineering student. However, his interest took a sudden turn when he got drawn towards biological sciences and ultimately decided to leave the engineering course by stepping into agribusiness management. “I realized I was walking in the right direction as I was fascinated to learn about the livelihood benefits of agroforestry and the scope of agribusiness in fostering overall economic growth.”

He joined CIMMYT in 2017 as an expert in market development, but his roles and responsibilities transitioned to working as a Lead for the Nepal Seed and Fertilizer (NSAF) project within four months of his appointment. His role involves leading an interdisciplinary team of scientists, partners and experts to develop a synergistic market system. The NSAF team fosters public private partnerships, improves access to support services and strengthens inclusive value chains in a supportive policy environment.

Choudhary’s research focuses on assessing crops, seed and fertilizer value chains; developing commercial and inclusive upgrading strategies with businesses and stakeholders; assessing competitiveness of seed companies; lobbying for policies to foster the growth of seed and fertilizer business; and building pathways for public and private sector services to market actors and smallholder farmers.

Dyutiman Choudhary (seventh from left) with seed producers during a field visit. (Photo: Dipak Kafle)

A roadmap to innovative market systems

Choudhary introduced the vision of a market system approach and put together a strategic roadmap in collaboration with a team from CIMMYT researchers from the Global Maize program, the Sustainable Intensification program and the Socioeconomics program. The roadmap addressed the concerns of low crop productivity, poor private sector growth and a less supportive policy environment inhibiting agricultural innovations in Nepal.

“Seed and fertilizer market systems in Nepal are uncompetitive and lack influx of new knowledge and innovations that restricts agriculture growth,” Choudhary explained.

Having prior experience as a regional lead for high-value products and value chains for South Asia and an inclusive market-oriented development expert in Eastern and Southern Africa, Choudhary carries unique capabilities for putting together a winning team and working with diverse partners to bring about a change in farming practices and build a strong agribusiness sector in Nepal.

Under his leadership, Nepalese seed companies are implementing innovative and competitive marketing approaches to develop newly acquired hybrid varieties under their brands. The companies are upgrading to build business models that cater to the growth of seed business, meet market demands and offer innovative services to smallholder farmers to build a sustainable national market. Facilitating financing opportunities has enabled these enterprises to produce strategic business plans to leverage $2 million to finance seed business. Improved value chain coordination mechanisms are increasing demand of seed company’s products and enhancing smallholder farmers’ access to output markets.

There is a renewed interest and confidence beaming from the private sector to invest in fertilizer business due to improved knowledge, communication and collaborative methods. The government committed to support balanced soil fertility management and allocated $2.4 million in 2019 to initiate fertilizer blending in Nepal.

The landscape is changing, and policy makers are considering new ideas to strengthen the delivery of targets under the Government of Nepal’s National Seed Vision 2013-2025 and the Agriculture Development Strategy 2015-2035.

Dyutiman Choudhary (left) welcomes the Feed the Future team leader to the CIMMYT office in Nepal. (Photo: Bandana Pradhan/CIMMYT)

Dyutiman Choudhary shows a demonstration plot during a field visit with USAID and project partners in Nepal. (Photo: Darbin Joshi)

Dyutiman Choudhary (left) receives a token of appreciation at an International Seed Conference organized in Nepal. (Photo: Bandana Pradhan/CIMMYT)

Competitiveness fosters productivity

The results of Choudhary’s work have the potential to transform Nepalese agriculture by unleashing new investments, changes in policies and practices, and innovative business management practices. “Despite a huge change in my TOR and the challenges to deliver impactful outcomes, I was able to successfully steer the project to produce exciting results that made the donor to declare it as their flagship project in Nepal,” he explained. “At the end of the day, reflecting upon the work achieved with my team and the stakeholders in co-creating solutions for complex issues brings me immense satisfaction.”

An amiable individual, he feels close to natural science and loves interacting with farmers. “I’ve always enjoyed traveling to biodiversity-rich locations, to understand local cultures and livelihood practices, so as to gauge the drivers of innovation and adaptation to change among diverse rural populations.”

“Keeping up the momentum, I want to continue to support growth in agribusiness management in less favorable regions, helping stakeholders in the farm-to-fork continuum to leverage the potential of innovations in research, development and delivery.”

Digital nutrient management tool reduces emissions, improves crop yields and boosts farmers’ profits

Written by Alison Doody on January 15, 2021. Posted in News.

An international team of scientists, led by the International Maize and Wheat Improvement Center (CIMMYT), has demonstrated how better nutrient management using digital tools, such as the Nutrient Expert decision support tool, can boost rice and wheat productivity and increase farmers’ income while reducing chemical fertilizer use and greenhouse gas emissions.

Reported today in Nature Scientific Reports, the results show how the farmer-friendly digital nutrient management tool can play a key role in fighting climate change while closing the yield gap and boosting farmers’ profits.

The researchers tested the Nutrient Expert decision tool against typical farmer fertilization practices extensively using approximately 1600 side-by side comparison trials in rice and wheat fields across the Indo-Gangetic Plains of India.

The study found that Nutrient Expert-based recommendations lowered global warming potential by 12-20% in wheat and by around 2.5% in rice, compared to conventional farmers’ fertilization practices. Over 80% of farmers were also able to increase their crop yields and incomes using the tool.

Agriculture is the second largest contributor of greenhouse gas emissions in India. To tackle these emissions, crop scientists have been working on new ways to make farming more nutrient- and energy-efficient. Of the many technologies available, improving nutrient-use-efficiency through balanced fertilizer application — which in turn reduces excess fertilizer application — is key to ensuring food security while at the same time contributing to the UN’s Sustainable Development Goals on climate change.

The work was carried out by CIMMYT in collaboration with farmers, and funded by the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), the CGIAR Research Program on Wheat (WHEAT), and the Indian Council of Agricultural Research (ICAR). Scientists from the Borlaug Institute for South Asia (BISA), the International Rice Research Institute (IRRI), the Alliance of Bioversity International and CIAT, and the former International Plant Nutrition Institute (IPNI) also contributed to this study.

Researchers tested the Nutrient Expert decision tool against typical farmer fertilization practices extensively using approximately 1600 side-by side comparison trials in rice and wheat fields across the Indo-Gangetic Plains of India (Graphic: CIMMYT).

Precise recommendations

Nutrient Expert, which was launched back in 2013, works by analysing growing conditions, natural nutrients in the soil, and even leftover nutrients from previous crops to provide tailored fertilizer recommendations directly to farmers phones. The tool also complements the Government of India’s Soil Health Cards for balanced and precise nutrient recommendations in smallholder farmers’ fields.

Each farmer’s field is different, which is why blanket fertilizer recommendations aren’t always effective in producing better yields. By using nutrient management tools such as Nutrient Expert, farmers can obtain fertilizer recommendations specific to the conditions of their field as well as their economic resources and thus avoid under-fertilizing or over-fertilizing their fields.

“While efficient nutrient management in croplands is widely recognized as one of the solutions to addressing the global challenge of supporting food security in a growing global population while safeguarding planetary health, Nutrient Expert could be an important tool to implement such efficient nutrient management digitally under smallholder production systems,” said Tek Sapkota, CIMMYT climate scientist and first author of the study.

Sapkota also argues that adoption of the Nutrient Expert tool in rice-wheat systems of India alone could provide almost 14 million tonnes (Mt) of extra grain with 1.4 Mt less nitrogen fertilizer use, and a reduction of 5.3 Mt of carbon (CO2) emissions per year over current practices.

However, technological innovation alone will not achieve these positive outcomes.

“Given the magnitude of potential implications in terms of increasing yield, reducing fertilizer consumption and greenhouse gas emissions, governments need to scale-out Nutrient Expert-based fertilizer management through proper policy and institutional arrangements, especially for making efficient use of the nearly 200 million Soil Health Cards that were issued to farmers as part of the Soil Health mission of the Government of India,” said ML Jat, CIMMYT principal scientist and co-author of the study.

Read the study:
Crop nutrient management using Nutrient Expert improves yield, increases farmers’ income and reduces greenhouse gas emissions.

A young man uses a precision spreader to distribute fertilizer in a field. (Photo: Mahesh Maske/CIMMYT)

Too much or never enough

Written by Emma Orchardson on December 4, 2020. Posted in Blogs.

Although nitrogen has helped in contributing to human dietary needs, there are still large areas of the world — namely sub-Saharan Africa and parts of Asia — that remain short of the amounts they need to achieve food and nutritional security.

Conversely, synthetic nitrogen has become increasingly crucial in today’s intensive agricultural systems, but nearly half of the fertilizer nitrogen applied on farms leaks into the surrounding environment. It is possible that we have now transgressed the sustainable planetary boundary for nitrogen, and this could have devasting consequences.

Given this conflicting dual role this compound plays in agricultural systems and the environment — both positive and negative — the nitrogen challenge is highly relevant across most of the 17 Sustainable Development Goals (SDGs) established by the United Nations.

Facing a global challenge

The challenge of nitrogen management globally is to provide enough nitrogen to meet global food security while minimizing the flow of unused nitrogen to the environment. One of the key approaches to addressing this is to improve nitrogen use efficiency – which not only enhances crop productivity but also minimizes environmental losses through careful agronomic management – and measures to improve soil quality over time.

Globally, average nitrogen use efficiency does not exceed 50%. Estimates show that a nitrogen use efficiency will need to reach 67% by 2050 if we are to meet global food demand while keeping surplus nitrogen within the limits for maintaining acceptable air and water qualities to meet the SDGs.

This target may seem ambitious — especially given the biological limits to achieving a very high nitrogen use efficiency — but it is achievable.

Earlier this year, J.K. Ladha and I co-authored a paper outlining the links between nitrogen fertilizer use in agricultural production systems and various SDGs. For instance, agricultural systems with suboptimal nitrogen application are characterized with low crop productivity, spiraling into the vicious cycle of poverty, malnutrition and poor economy, a case most common in the sub-Saharan Africa. These essentially relate to SDG 1 (no-poverty), 2 (zero-hunger), 3 (good health and well-being), 8 (decent work and economic growth) and 15 (life on land).

On the other hand, excess or imbalanced fertilizer nitrogen in parts of China and India have led to serious environmental hazards, degradation of land and economic loss. Balancing the amount of N input in these regions will contribute in achieving the SDG 13 (climate action). Equally, meeting some of the additional SDGs (5, gender equality; 6, clean water and sanitation; 10: reduced inequalities; etc.) requires optimum nitrogen application, which will also ensure “responsible consumption and production” (SDG 12).

A diagram shows the impact of fertilizer nitrogen use on the achievement of the Sustainable Development Goals. (Graphic: CIMMYT/Adapted from CCAFS)

So, how can we achieve this?

Increased research quantifying the linkages between nitrogen management and the SDGs will be important, but the key to success lies with raising awareness among policy makers, stakeholders and farmers.

Most agricultural soils have considerably depleted levels of soil organic matter. This is a central problem that results in agroecosystems losing their ability to retain and regulate the supply of nitrogen to crops. However, poor knowledge and heavy price subsidies are equally to blame for the excess or misuse of nitrogen.

While numerous technologies for efficient nitrogen management have been developed, delivery mechanisms need to be strengthened, as does encouragement for spontaneous adaptation and adoption by farmers. Equally — or perhaps more importantly — there is a need to create awareness and educate senior officials, policy makers, extension personnel and farmers on the impact of appropriate soil management and intelligent use of nitrogen fertilizer, in conjunction with biologically integrated strategies for soil fertility maintenance.

An effective and aggressive campaign against the misuse of nitrogen will be effective in areas where the compound is overused, while greater accessibility of nitrogen fertilizer and policies to move farmers towards soil quality improvement will be essential in regions where nitrogen use is currently sub-optimal.

It is only through this combination of approaches to improved system management, agricultural policies and awareness raising campaigns that we can sufficiently improve nitrogen use efficiency — and meet the SDGs before it’s too late.

Read the full study “Achieving the sustainable development goals in agriculture: the crucial role of nitrogen in cereal-based systems” in Advances in Agronomy.

A collage of shows images relating to different stages of the nitrogen cycle. (Graphic: Alfonso Cortés/CIMMYT)

Nitrogen in agriculture

Written by Emma Orchardson on December 4, 2020. Posted in Explainers.

Nitrogen is the most essential nutrient in crop production but also one of the most challenging to work with. The compound is central to global crop production — particularly for major cereals — but while many parts of the world do not have enough to achieve food and nutrition security, in others excess nitrogen from fertilizer leaks into the environment with damaging consequences.

What is nitrogen?

Around 78% of the Earth’s atmosphere is made up of nitrogen gas or N2 — a molecule made of two nitrogen atoms glued together by a stable, triple bond.

Though it makes up a large portion of the air we breathe, most living organisms can’t access it in this form. Atmospheric nitrogen must go through a natural process called nitrogen fixation to transform before it can be used for plant nutrition.

Why do plants need nitrogen?

In both plants and humans, nitrogen is used to make amino acids — which make the proteins that construct cells — and is one of the building blocks for DNA. It is also essential for plant growth because it is a major component of chlorophyll, the compound by which plants use sunlight energy to produce sugars from water and carbon dioxide (photosynthesis).

The nitrogen cycle

The nitrogen cycle is the process through which nitrogen moves from the atmosphere to earth, through soils and is released back into the atmosphere — converting in and out of its organic and inorganic forms.

It begins with biological nitrogen fixation, which occurs when nitrogen-fixing bacteria that live in the root nodules of legumes convert organic matter into ammonium and then nitrate. Plants are able to absorb nitrate from the soil and break it down into the nitrogen they need, while denitrifying bacteria convert excess nitrate back into inorganic nitrogen which is released back into the atmosphere.

The process can also begin with lightning, the heat from which ruptures the triple bonds of atmospheric nitrogen, freeing its atoms to combine with oxygen and create nitrous oxide gas, which dissolves in rain as nitric acid and is absorbed by the soil.

Excess nitrate or that lost through leaching — in which key nutrients are dissolved due to rain or irrigation — can seep into and pollute groundwater streams.

A diagram shows the process through which nitrogen moves from the atmosphere to earth, through soils and is released back into the atmosphere – converting in and out of its organic and inorganic forms. (Graphic: Nancy Valtierra/CIMMYT)

What about nitrogen fertilizer?

For thousands of years, humans didn’t need to worry about nitrogen, but by the turn of the Twentieth Century it was evident that intensive farming was depleting nitrate in the soil, which raised concerns about the world’s rising population and a possible food crisis.

In 1908, a German chemist named Fritz Haber devised a process for combining atmospheric nitrogen and hydrogen under extreme heat and pressure to create liquid ammonia — a synthetic nitrogen fertilizer. He later worked with chemist and engineer Carl Bosch to industrialize this process and make it commercially available for farmers.

Once production was industrialized, synthetic nitrogen fertilizer — used in combination with new, high-yielding seed varieties — helped drive the Green Revolution and significantly boost global agricultural production from the late 1960s onwards. During this time Mexico became self-sufficient in wheat production, as did India and Pakistan, which were on the brink of famine.

In today’s intensive agricultural systems, synthetic nitrogen fertilizer has become increasingly crucial. Worldwide, companies currently produce over 100 million metric tons of this product every year, and the Food and Agriculture Organization of the United Nations predicts that demand will continue to rise steadily, especially in Africa and South Asia.

Is it sustainable?

As demand continues to rise worldwide, the challenge of nitrogen management is to provide enough to meet global food security needs while minimizing the flow of unused nitrogen — which is 300 times more polluting than carbon dioxide — to the environment.

While many regions remain short of available nitrogen to achieve food and nutrition security, in others nearly half of the fertilizer nitrogen applied in agriculture is leaked into the environment, with negative consequences including increased environmental hazards, irreparable land degradation and the contamination of aquatic resources.

This challenge can be addressed by improving nitrogen use efficiency — a complex calculation which often involves a comparison between crop biomass (primarily economic yield) or nitrogen content/uptake (output) and the nitrogen applied (input) through any manure or synthetic fertilizer. Improving this ratio not only enhances crop productivity but also minimizes environmental losses through careful agronomic management and helps improve soil quality over time.

Currently, average global nitrogen use efficiency does not exceed 50%, which falls short of the estimated 67% needed to meet global food demand in 2050 while keeping surplus nitrogen within the limits for maintaining acceptable air and water qualities.

Cutting-edge technological options for nitrogen management are on the horizon, though in the short-term nitrogen use efficiency can best be improved at farmer-level, by targeting fertilizer application, use of slow-release nitrogen fertilizers, using precision nitrogen application tools (Green Seeker) or fertigation using micro irrigation.

A woman in India uses a precision spreader to apply fertilizer on her farm. (Photo: Wasim Iftikar)

Blue-sky technology

Much progress has been made in developing technologies for an efficient nitrogen management, which along with good agronomy are proven to enhance crop nitrogen harvest and nitrogen use efficiency with lower surplus nitrogen.

Scientists are investigating the merits of biological nitrification inhibition, a process through which a plant excretes material which influences the nitrogen cycle in the soil. Where this process occurs naturally — in some grasses and wheat wild relatives — it helps to significantly reduce nitrogen emissions.

In 2007, scientists discovered biological nitrification traits in a wheat relative and in 2018 they succeeded in transferring them into a Chinese spring wheat variety. The initial result showed low productivity and remains in the very early stages of development, but researchers are keen to assess whether this process could be applied to commercial wheat varieties in the future. If so, this technology could be a game changer for meeting global nitrogen use efficiency goals.

A farmer assesses soil on his plot in Ethiopia. (Photo: Simret Yasabu/CIMMYT)

Taking stock of the national toolbox

Written by Emma Orchardson on November 19, 2020. Posted in Features.

The Government of Ethiopia has consistently prioritized agriculture and sees it as a core component of the country’s growth. However, despite considerable efforts to improve productivity, poor management of soil health and fertility has been an ongoing constraint. This is mainly due to a lack of comprehensive site-and context-specific soil health and fertility management recommendations and dissemination approaches targeted to specific needs.

The government envisions a balanced soil health and fertility system that helps farmers cultivate and maintain high-quality and fertile soils through the promotion of appropriate soil-management techniques, provision of required inputs, and facilitation of appropriate enablers, including knowledge and finance.

So far, a plethora of different research-for-development activities have been carried out in support of this effort, including the introduction of tools which provide location-specific fertilizer recommendations. For example, researchers on the Taking Maize Agronomy to Scale in Africa (TAMASA) project, led by the International Maize and Wheat Improvement Center (CIMMYT), have created locally calibrated versions of Nutrient Expert® (NE) — a tool for generating fertilizer recommendations — for maize farmers in Ethiopia, Nigeria and Tanzania.

Nutrient Expert® is only one of the many fertilizer recommendation tools which have been developed in recent years covering different levels of applicability and accuracy across spatial scales and users, including smallholder farmers, extension agents and national researchers. However, in order to make efficient use of all the resources available in Ethiopia, there is a need to systematically evaluate the merits of each tool for different scales and use cases. To jump start this process, researchers from the TAMASA project commissioned an assessment of the tools and frameworks that have been developed, adapted and promoted in the country, and how they compare with one another for different use-cases. Seven tools were assessed, including Nutrient Expert®, the Ethiopian Soil Information System (EthioSIS) and RiceAdvice.

For each of these, the research team asked determined how the tool is currently being implemented — for example, as an app or as a generic set of steps for recommendation generation — and its data requirements, how robust the estimates are, how complicated the interface is, how easy it is to use, the conditions under which it performs well, and the spatial scale at which it works best.

Farmer Gudeye Leta harvests his local variety maize in Dalecho village, Gudeya Bila district, Ethiopia. (Photo: Peter Lowe/CIMMYT)

Combining efforts and information

The results of this initial assessment indicate that the type of main user and the scale at which decisions are made varied from tool to tool. In addition, most of the tools considered have interactive interfaces and several — including Nutrient Expert® and RiceAdvice — have IT based platforms to automate the optimization of fertilizer recommendations and/or analyze profit. However, the source codes for all the IT based platforms and tools are inaccessible to end-users. This means that if further evaluation and improvements are to be made, there should be a means of collaborating with developers to share the back-end information, such as site-specific response curves and source codes.

Because most of the tools take different approaches to making fertilizer application site-specific, each of them renders unique strengths and trade-offs. For example, Nutrient Expert® may be considered strong in its approach of downscaling regionally calibrated responses to field level recommendations based on a few site-specific responses from farmers. By contrast, its calibration requires intensive data from nutrient omission trials and advice provision is time consuming.

Overall, the use of all the Site-Specific Decision-Support Tools (SSDST) has resulted in improved grain yields compared to when farmers use traditional practices, and this is consistent across all crops. On average, use of Nutrient Expert® improved maize, rice and wheat yields by 5.9%, 8.1% and 4.9%, respectively. Similarly, the use of RiceAdvice resulted in a 21.8% yield advantage.

The assessment shows that some of the tools are useful because of their applicability at local level by development agents, while others are good because of the data used to develop and validate them. However, in order to benefit the agricultural system in Ethiopia from the perspective of reliable fertilizer-use advisory, there is a need to develop a platform that combines the merits of all available tools. To achieve this, it has been suggested that the institutions who developed the individual tools join forces to combine efforts and information, including background data and source codes for IT based tools.

While the COVID-19 pandemic has disrupted efforts to convene discussions around this work, CIMMYT has and will continue to play an active advocacy role in supporting collaborative efforts to inform evidence-based reforms to fertilizer recommendations and other agronomic advice in Ethiopia and the wider region. CIMMYT is currently undertaking a more rigorous evaluation of these tools and frameworks as a follow up on the initial stocktaking activity.

Dharma Devi Chaudhary (right) stands next to her flourishing cauliflower crop in Kailali, Nepal. (Photo: Uttam Kunwar/CIMMYT)

Balanced fertilizer application boosts smallholder incomes

Written by Emma Orchardson on November 13, 2020. Posted in Blogs.

Agriculture is largely feminized in Nepal, where over 80% of women are employed in the sector. As a result of the skills gap caused by male out-migration, many women farmers are now making conscious efforts to learn techniques that can help improve yields and generate greater income — such as balanced fertilizer application — with support from the International Maize and Wheat Improvement Center (CIMMYT).

Studies have shown that many farmers lack knowledge of fertilizer management, but balanced fertilizer application using the right ratio of nutrients is key to helping crops thrive Through the Nepal Seed and Fertilizer (NSAF) project, CIMMYT researchers are working towards promoting precision nutrient management through multiple trials and demonstrations in farmers’ fields.

Through this initiative, Dharma Devi Chaudhary, a smallholder farmer from Kailali district, has been able to increase her annual earnings by adopting balanced fertilizer application in cauliflower cultivation — a key cash crop for the winter season in Nepal’s Terai region.

Her inspiration to use micronutrients such as boron came from the results she witnessed during a CIMMYT-supported demonstration conducted on her land in 2018. During the demonstration, Chaudhary learned the principles of the four ‘Rs’ of nutrient stewardship: the right rate, the right time, the right source and the right placement of fertilizers. She became familiar with different types of fertilizer and the amount to be used, as well as the appropriate time and place to apply urea top-dressing, diammonium phosphate (DAP) and muriate of potash (MoP) for optimal utilization by the plant.

Chaudhary also learned how boron application can increase crop yields while helping prevent plant diseases, especially in cauliflower, where boron deficiency can lead to a disorder known as ‘dead heart’ and cause significant yield loss. This is particularly useful knowledge for farmers in Nepal, where the boron content in soil is generally low.

A digital soil map developed by the NSAF project shows medium to high boron deficiency in Kailali district and the surrounding area. (Map: CIMMYT) — A digital soil map developed by researchers on the NSAF project shows medium-to-high boron deficiency in Kailali district. (Map: CIMMYT)

Benefitting from best practices

Cauliflower is cultivated on 615 hectares of land across Kailali and produces a yield of 15 tons per hectare — far less than the potential yield of 35-40 tons. As a standard practice, farmers in the area have been applying nitrogen, phosphorous and potassium (NPK) at a ratio of 27: 27.6: 9 kilograms per hectare and three tons of farmyard manure per hectare. During a CIMMYT-led demonstration on a small parcel of land, Chaudhary observed that balanced fertilizer application yielded about 64% more than when using her traditional practices, fetching her an income of $180 that season compared to her usual $109.

Following this demonstration, Chaudhary decided to independently cultivate cauliflower on a plot of 500 square meters, where she applied farmyard manure two weeks before transplantation and then used DAP, MOP, boron and zinc as a basal application during transplanting. She also applied urea in split doses, first at 25 days and then 50 days after transplantation. Using this technique, Chaudhary was able to yield 46 tons of cauliflower per hectare, nearly twice as much as was yielded by farmers using traditional practices. As a result, she was able to generate an income increase of $800 for her household, compared to the previous season’s earnings.

“I was able to buy education resources, clothing and more food supplies for my children with the additional income I earned from selling cauliflower last year,” said Chaudhary. “Learning about the benefits of using micronutrients is essential for smallholder farmers like me who are looking for ways to improve their farming business.”

Smallholder farmers tend to be risk averse, which can make technology adoption difficult. However, on-farm demonstrations help reduce the risks farmers perceive and facilitate new technology adoption easily by exhibiting encouraging results.

Chaudhary now serves as a lead farmer at Janasewa Krishak Multi-purpose Cooperative and supports the organization by disseminating knowledge on balanced fertilizer management practices to hundreds of farmers in her community. After seeing the impact of adopting the recommended techniques, the use of balanced fertilizer is reaping benefits for other farmers in her district, helping them achieve better income from higher crop yields and maintain soil fertility in their area.