Tag: crop rotation

Sowing seeds of change to champion Conservation Agriculture

Written by Julian Bañuelos-Uribe on July 29, 2024. Posted in Blogs.

Florence Mutize’s thriving fields of maize, in Bindura, a small town in Mashonaland Central region of Zimbabwe, serve as living proof of the successes of Conservation Agriculture (CA), a sustainable cropping system that helps reverse soil degradation, augment soil health, increase crop yields, and reduce labor requirements while helping farmers adapt to climate change. The seeds of her hard work are paying off, empowering her family through education and ensuring that a nutritious meal is always within reach.

“I have been dedicated to these CA trials since 2004, starting on a small plot,” said Mutize. “Now, with years of experience and adaptation to changing climates, I’ve seen my yields increase significantly, harvesting up to a tonne of maize on a 30 by 30m plot using direct seeding and ripping techniques together with crop residue to cover the soil and rotating maize with soybean.”

Mutize is one of many mother trial host farmers implementing CA principles through the CGIAR Ukama Ustawi regional initiative in Bindura. A mother trial is a research approach involving testing and validating a suite of climate-smart agriculture technologies to identify the best-performing ones which can then be adopted on a larger scale.

Nestled in the Mazowe valley, Bindura experiences a subtropical climate characterized by hot, dry summers and mild, wet winters, ideal for agricultural production. But the extremes of the changing climate, like imminent dry spells and El Niño-induced threats, are endangering local farmers. Yet, smallholder farmers like Mutize have weathered the extremes and continued conducting mother trials, supported by the agriculture extension officers of the Agricultural and Rural Development Advisory Services (ARDAS) Department of the Ministry of Lands, Agriculture, Fisheries, Water and Rural Development.

“Where I once harvested only five bags of maize, rotating maize with soybeans now yields 40 bags of maize and 10 bags of soybeans,” Mutize proudly shares.

The UU-supported CA program also extends to farmers in Shamva, like Elphas Chinyanga, another mother trial implementer since 2004.

Elphas Chinyanga and his son inspect maize cobs in their field. (Photo: CIMMYT)

“From experimenting with various fertilization methods to introducing mechanized options like ripping and direct seeding, these trials have continuously evolved,” said Chinyanga. “Learning from past experiences, we have gotten much more benefits and we have incorporated these practices into other fields beyond the trial area. I am leaving this legacy to my children to follow through and reap the rewards.”

Learning has been a crucial element in the dissemination of CA technologies, with CIMMYT implementing refresher training together with ARDAS officers to ensure that farmers continue to learn CA principles. As learning is a progressive cycle, it is important to package knowledge in a way that fits into current training and capacity development processes.

Pre-season refresher training with mother trial host farmers and extension in Hereford, Zimbabwe. (Photo: CIMMYT)

This process could also be labelled as “scaling deep” as it encourages farmers to move away from conventional agriculture technologies. Reciprocally, scientists have been learning from the experiences of farmers on the ground to understand what works and what needs improvement.

Inspired by the successes of his peers in Shamva, Hendrixious Zvomarima joined the program as a host farmer and saw a significant increase in yields and efficiency on his land.

“For three years, I have devoted time to learn and practice what other farmers like Elphas Chinyanga were practicing. It has been 14 years since joining, and this has been the best decision I have made as it has improved my yields while boosting my family’s food basket,” said Zvomarima.

The longevity and success of the initiative can be attributed to committed farmers like Mutize, Chinyanga, and Zvomarima, who have been part of the program since 2004 and are still executing the trials. Farmer commitment, progressive learning, and cultivating team spirit have been the success factors in implementing these trials. CIMMYT’s long-term advocacy and learning from the farmers has been key to a more sustainable, resilient, and empowered farming community.

Unlocking Zambia’s maize potential through crop diversity

Written by Julian Bañuelos-Uribe on July 24, 2024. Posted in Publications.

While maize is the primary staple food crop in Zambia, its productivity on farmers’ fields reaches on average only about 20 percent of what it could achieve with good agronomic practices. Some reasons for this inefficiency are use of traditional varieties, low fertilizer use, and ineffective weed and pest control.

Closing the gap between potential and realized yields would have major benefits for farmers in Zambia, both in terms of income and food security at the household and national levels. One possibility to increase maize productivity is by increasing crop diversity through the inclusion of legumes in maize-based farming systems. This could be done through intercropping, growing legumes in the rows between maize plants, or crop rotations and alternating maize and legumes in the same field from season to season.

CIMMYT scientists, along with collaborators from the Zambia Agriculture Research Institute (ZARI) and the University of Zambia’s School of Agricultural Science, set out to determine which cropping systems might lead to increased productivity for maize farmers in Zambia and their results were published in the journal Field Crops Research.

“There is great potential in Zambia to increase yields to help ensure food security,” said Mulundu Mwila, PhD candidate and scientist at ZARI. “We wanted to determine the cropping systems that offered the most benefits.”

Setting up the study

For this research, ZARI and CIMMYT scientists established maize-based cropping systems trials, comprising maize monocropping, and maize-legume rotations and intercrops under both ‘conventional’ tillage, and Conservation Agriculture, across 40 farms in a variety of agroecological zones in Zambia. The team also conducted household surveys in the same communities hosting the on-farm trials to determine the share of households with enough cultivated land to benefit from the tested cropping systems.

Researchers found that the tested cropping systems produced more maize per hectare compared to non-trial host farms in the same region. The greatest positive effect uncovered was that maize-legume rotations in Zambia’s Eastern Province had the potential to increase maize yield by 1 to 2 tons per hectare, per growing season. “The Eastern Province trials showed better results because of stable and adequate rainfall amounts and distribution and because of using groundnut as a rotation crop,” said Mwila.

Researchers attributed the small effect of legumes on maize yield in the Southern Province to low levels of biomass production and nitrogen fixation, due to low and erratic rainfall, and to low residue incorporation because of livestock grazing. Conversely, the small effect of legumes on maize yield in the Northern Province might be attributed to the high rainfall amount in the region, leading to high rates of leaching of residual nitrogen during the growing season as well as the use of common beans as the preceding crop.

Finding the right amount of land

With evidence showing the potential benefits of maize-legume rotations, the availability of land is a constraint for small farms across sub-Saharan Africa, thus it is important to quantify the land area needed for farmers to implement maize-legume rotations.

“Our findings match prior research showing the benefits of maize-legume rotations in Eastern Zambia” said Silva. “However, implementing maize-legume rotations remains a challenge for many smallholders due to small farm sizes.”

Nearly 35, 50, and 70% of the surveyed farms in the Northern, Eastern, and Southern Provinces, respectively, had enough land to achieve the same level of maize production obtained on their farm with the yields of the maize-legume rotations tested in the on-farm trials. “With our findings showing increased maize yields, and our efforts to determine the amount of land needed for food and nutrition security at household level, the next steps can be to facilitate methods to disseminate this information to policy makers and to farmers that have enough land area to benefit from diversified cropping systems,” said Silva.

For farmers with not enough land to reap the benefits of maize-legume rotations, intercropping legumes within the maize has shown promising results. The researchers also call for further research to specify the contributing factors to small farms not seeing benefits from maize-legume rotations.

Soybean rust threatens soybean production in Malawi and Zambia

Written by Julian Bañuelos-Uribe on January 25, 2024. Posted in Blogs.

Healthy soybean fields. (Photo: Peter Setimela/CIMMYT)

Soybeans are a significant source of oil and protein, and soybean demand has been increasing over the last decade in Malawi and Zambia. Soybean contributes to human nutrition, is used in producing animal feed, and fetches a higher price per unit than maize, thus serving as a cash crop for smallholder farmers. These are among the main factors contributing to the growing adoption of soybean among smallholder producers. In addition, soybean is a vital soil-fertility improvement crop used in crop rotations because of its ability to fix atmospheric nitrogen. To a large extent, soybean demand outweighs supply, with the deficit covered by imports.

Soybean production in sub-Saharan Africa is expected to grow by over 2% per annum to meet the increasing demand. However, as production increases, significant challenges caused by diseases, pests, declining soil fertility, and other abiotic factors remain. According to official government statistics, Zambia produces about 450,000 tonnes of soybean per annum, with an estimated annual growth of 14%. According to FAOSTAT, this makes Zambia the second largest soybean producer in the southern African region. Although soybean was traditionally grown by large commercial farmers in Zambia, smallholders now account for over 60% of the total annual soybean production.

Production trends show that smallholder soybean production increased rapidly in the 2015–2016 season, a period that coincided with increased demand from local processing facilities. As smallholder production continued to increase, in 2020, total output by smallholder farmers outpaced that of large-scale farmers for the first time and has remained dominant over the last two seasons (Fig 1). However, soybean yields among smallholder farmers have remained low at around 1 MT/HA.

Figure 1. Soybean production trends by smallholders and large-scale farmers. (Photo: Hambulo Ngoma/Zambia Ministry of Agriculture, Crop Forecast Survey)

Soybean production in the region is threatened by soybean rust caused by the fungus Phakopsora pachyrhizi. The rust became prevalent in Africa in 1996; it was first confirmed in Uganda on experimental plots and subsequently on farmers’ fields throughout the country. Monitoring efforts in the U.S. have saved the soybean industry millions of dollars in fungicide costs due to the availability of accurate disease forecasting based on pathogen surveillance and environmental data.

Soybean rust disease is spread rapidly and easily by wind, and most available varieties grown by farmers are susceptible. The above-normal rainfall during the 2022–2023 season was conducive to the spread of the fungus. A recent survey of over 1,000 farm households shows that 55% and 39% of farmers in Zambia and Malawi, respectively, were affected by soybean rust during the 2022–2023 season. The lack of rust-tolerant varieties makes production expensive for smallholder farmers who cannot afford to purchase fungicides to control the pathogens. It is estimated that soybean rust can cause large yield losses of up to 90%, depending on crop stage and disease severity. Symptoms due to soybean rust infection may be observed at any developmental stage of the plant, but losses are mostly associated with infection from the flowering stage to the pod-filling stage.

Soybean plants affected by soy rust. (Photo: Peter Setimela)

Mitigation measures using resistant or tolerant varieties have been challenging because the fungus mutates very rapidly, creating genetic variability. Although a variety of fungicides effective against soybean rust are available, the use of such fungicides is limited due to the high cost of the product and its application, as well as to environmental concerns. Due to this restricted use of fungicide, an early monitoring system for detecting rust threats for steering fungicide might only be relevant for large-scale producers in eastern and southern Africa. With the massive increase in the area under soybean production, soybean rust is an important disease that cannot be ignored. Host-plant resistance provides a cheaper, more environmentally friendly, and much more sustainable approach for managing soybean rust in smallholder agriculture that characterizes the agricultural landscape of eastern and southern Africa.

To advance the use of rust-tolerant varieties, the Southern Africa Accelerated Innovation Delivery Initiative (AID-I) Rapid Delivery Hub, or MasAgro Africa, is presently concluding surveys to assess farmers’ demand and willingness to pay for rust-tolerant varieties in Malawi and Zambia. The results from this assessment will be valuable to seed companies and last-mile delivery partners to gain a better understanding of what farmers need and to better serve the farmers. This coming season AID-I will include rust tolerant varieties in the mega-demonstrations to create awareness about new varieties that show some tolerance to rust.

Sequestering carbon in soils: what agriculture can do

Written by mcallejas on November 30, 2023. Posted in In the media.

In Zimbabwe, CIMMYT is studying the long-term effectiveness of integrated farming practices, including tillage, no-tillage, mulching with maize residues, and cowpea rotation. This experiment in a distinct agricultural context provides insights into sustainable strategies and soil carbon stocks.

Read the full story.

A researcher from the Borlaug Institute for South Asia (BISA) walks through a wheat field in India. (Photo: BISA)

Solving South Asia’s sustainability issues will require a systems approach to crop management

Written by Alison Doody on December 17, 2020. Posted in News.

New research by an international team of scientists, including scientists from the International Maize and Wheat Improvement Center (CIMMYT) and the Indian Council of Agricultural Research (ICAR), shows that adopting a portfolio of conservation agriculture and crop diversification practices is more profitable and better for the environment than conventional agriculture.

Reported last month in Nature Scientific Reports, the results of the study should encourage farmers and policymakers in South Asia to adopt more sustainable crop management solutions such as diversifying crop rotations, direct-seeding rice, zero tillage and crop residue retention.

Rice-wheat has for a long time been the dominant cropping system in the western Indo-Gangetic plains in India. However, issues such as water depletion, soil degradation and environmental quality as well as profitability have plagued farmers, scientists and decision makers for decades. To tackle these issues, researchers and policymakers have been exploring alternative solutions such as diversifying rice with alternative crops like maize.

“Climate change and natural resource degradation are serious threats to smallholder farmers in South Asia that require evidence-based sustainable solutions. ICAR have been working closely with CIMMYT and partners to tackle these threats,” said SK Chaudhari, deputy director general of the Natural Resource Management at ICAR.

In the study, CIMMYT scientists partnered with the ICAR-Central Soil Salinity Research Institute, International Rice Research Institute (IRRI), Borlaug Institute for South Asia (BISA), Swami Keshwan Rajasthan Agriculture University and Cornell University to evaluate seven cropping system management scenarios.

The researchers measured a business-as-usual approach, and six alternative conservation agriculture and crop diversification approaches, across a variety of indicators including profitability, water use and global warming potential.

Wheat grows under a systematic intensification approach at the Borlaug Institute for South Asia (BISA) in India. (Photo: BISA)

They found that conservation agriculture-based approaches outperformed conventional farming approaches on a variety of indicators. For example, conservation agriculture-based rice management was found to increase profitability by 12%, while decreasing water use by 19% and global warming potential by 28%. Substituting rice with conservation agriculture-based maize led to improvements in profitability of 16% and dramatic reductions in water use and global warming potential of 84% and 95%. Adding the fast-growing legume mung bean to maize-wheat rotations also increased productivity by 11%, profitability by 25%, and significantly decreased water use by 64% and global warming potential by 106%.

However, CIMMYT Principal Scientist and study co-author M.L. Jat cautioned against the allure of chasing one silver bullet, advising policymakers in South Asia to take a holistic, systems perspective to crop management.

“We know that there are issues relating to water and sustainability, but at the same time we also know that diversifying rice — which is a more stable crop — with other crops is not easy as long as you look at it in isolation,” he explained. “Diversifying crops requires a portfolio of practices, which brings together sustainability, viability and profits.”

With South Asia known as a global “hotspot” for climate vulnerability, and the region’s population expected to rise to 2.4 billion by 2050, food producers are under pressure to produce more while minimizing greenhouse gas emissions and damage to the environment and other natural resources.

“Tackling these challenges requires strong collaborative efforts from researchers, policymakers, development partners and farmers,” said Andrew McDonald, a systems agronomist at Cornell University and co-author of the study. “This study shows this collaboration in action and brings us closer to achieving resilient, nutritious and sustainable food systems.”

“The results of this study show that one-size doesn’t fit all when it comes to sustainable crop management,” said PC Sharma, director of India’s ICAR-Central Soil Salinity Research Institute (ICAR-CSSRI). “Farmers, researchers and policymakers can adopt alternative crop rotations such as maize-wheat or maize-wheat-mung bean, but they can also improve existing rice-wheat rotations using conservation agriculture methods.”