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Theme: Environmental health and biodiversity

The world needs better management of water, soil, nutrients, and biodiversity in crop, livestock, and fisheries systems, coupled with higher-order landscape considerations as well as circular economy and agroecological approaches.

CIMMYT and CGIAR use modern digital tools to bring together state-of-the-art Earth system observation and big data analysis to inform co-design of global solutions and national policies.

Our maize and wheat genebanks preserve the legacy of biodiversity, while breeders and researchers look at ways to reduce the environmental footprint of agriculture.

Ultimately, our work helps stay within planetary boundaries and limit water use, nutrient use, pollution, undesirable land use change, and biodiversity loss.

What is green manure? And how is it helping maize farmers?

Farmer Eveline Musafari intercrops maize and a variety of legumes on her entire farm. She likes the ability to grow different food crops on the same space, providing her family with more food to eat and sell. (Photo: Matthew O’Leary/CIMMYT)
Farmer Eveline Musafari intercrops maize and a variety of legumes on her entire farm. She likes the ability to grow different food crops on the same space, providing her family with more food to eat and sell. (Photo: Matthew O’Leary/CIMMYT)

Honest Musafari, a fifty-year-old farmer from rural Zimbabwe, eagerly picks up a clump of soil from his recently harvested field to show how dark and fertile it is. A farmer all his life, Musafari explains the soil has not always been like this. For years, he and his neighbors had to deal with poor eroding soil that increasingly dampened maize yields.

“My soil was getting poorer each time I plowed my field, but since I stopped plowing, left the crop residues and planted maize together with legumes the soil is much healthier,” says Musafari. His 1.6-hectare maize-based farm, in the Murehwa district, supports his family of six.

For over two years, Musafari has been one of the ten farmers in this hot and dry area of Zimbabwe to trial intercropping legumes and green manure cover crops alongside their maize, to assess their impact on soil fertility.

The on-farm trials are part of efforts led by the International Maize and Wheat Improvement Center (CIMMYT) in collaboration with Catholic Relief Services (CRS) and government extension services to promote climate-resilient cropping systems in sub-Saharan Africa.

Increasing land degradation at the farm and landscape level is the major limitation to food security and livelihoods for smallholder farmers in sub-Saharan Africa, says CIMMYT senior cropping systems agronomist Christian Thierfelder.

Over 65 percent of soils in Africa are degraded. They lack the nutrients needed for productive crops. This is a major part of the reason why the region’s maize yields are not increasing,” he explains. “The failure to address poor soil health will have a disastrous effect on feeding the region’s growing population.”

The area where Musafari lives was chosen to test intercropping, along with others in Malawi and Zambia, for their infamous poor soils.

Mixing it up

When legumes are intercropped with maize they act as a green manure adding nutrients to the soil through nitrogen fixation. Intercropping legumes and cereals along with the principles of conservation agriculture are considered away to sustainable intensify food production in Africa. (Photo: Christian Thierfelder/CIMMYT)
When legumes are intercropped with maize they act as a green manure adding nutrients to the soil through nitrogen fixation. Intercropping legumes and cereals along with the principles of conservation agriculture are considered away to sustainable intensify food production in Africa. (Photo: Christian Thierfelder/CIMMYT)

Planted in proximity to maize, legumes — like pigeon pea, lablab and jack beans — add nitrogen to the soil, acting as green manure as they grow, says Thierfelder. Essentially, they replace the nutrients being used by the cereal plant and are an accessible form of fertilizer for farmers who cannot afford mineral fertilizers to improve soil fertility.

“Our trials show legumes are a win for resource poor family farmers. Providing potentially 5 to 50 tons per hectare of extra organic matter besides ground cover and fodder,” he notes. “They leave 50 to 350 kg per hectare of residual nitrogen in the soil and do not need extra fertilizer to grow.”

Added to the principles of conservation agriculture — defined by minimal soil disturbance, crop residue retention and diversification through crop rotation and intercropping — farmers are well on their way to building a resilient farm system, says Geoffrey Heinrich, a senior technical advisor for agriculture with CRS working to promote farmer adoption of green manure cover crops.

For years Musafari, as many other smallholder farmers in Africa, tilled the land to prepare it for planting, using plows to mix weeds and crop residues back into the soil. However, this intensive digging has damaged soil structure, destroyed most of the organic matter, reduced its ability to hold moisture and caused wind and water erosion.

Letting the plants do the work

Growing legumes alongside maize provides immediate benefits, such as reduced weeding labor and legume cash crops farmers can sell for a quick income. The legumes also improve the nitrogen levels in the soil and can save farmers money, as maize needs less fertilizer. (Photo: Christian Thierfelder/CIMMYT)
Growing legumes alongside maize provides immediate benefits, such as reduced weeding labor and legume cash crops farmers can sell for a quick income. The legumes also improve the nitrogen levels in the soil and can save farmers money, as maize needs less fertilizer. (Photo: Christian Thierfelder/CIMMYT)

Musafari says the high price of mineral fertilizer puts it out of reach for farmers in his community. They only buy little amounts when they have spare cash, which is never enough to get its full benefit.

He was at first skeptical green manure cover crops could improve the quality of his soil or maize yields, he explains. However, he thought it was worth a try, considering growing different crops on the same plot would provide his family with more food and the opportunity to make some extra cash.

“I’m glad I tried intercropping. Every legume I intercropped with my maize improved the soil structure, its ability to capture rain water and also improved the health of my maize,” he says.

Thierfelder describes how this happens. Nitrogen fixation, which is unique to leguminous crops, is a very important process for improving soil fertility. This process involves bacteria in the soil and nitrogen in the air. The bacteria form small growths on the plant roots, called nodules, and capture the atmospheric nitrogen as it enters the soil. The nodules change the nitrogen into ammonia, a form of nitrogen plants use to produce protein.

In addition, legumes grown as a cover crop keep soil protected from heavy rains and strong winds and their roots hold the soil in place, the agronomist explains. They conserve soil moisture, suppress weeds and provide fodder for animals and new sources of food for consumption or sale.

Farmers embrace intercropping

Extension worker Memory Chipinguzi explains the benefits of intercropping legumes with cereals to farmers at a field day in the Murehwa district, Zimbabwe. (Photo: Christian Thierfelder/CIMMYT)
Extension worker Memory Chipinguzi explains the benefits of intercropping legumes with cereals to farmers at a field day in the Murehwa district, Zimbabwe. (Photo: Christian Thierfelder/CIMMYT)

Working with CIMMYT, Musafari and his wife divided a part of their farm into eight 20 by 10 meter plots. On each plot, they intercropped maize with a different legume: cowpea, jack bean, lablab, pigeon pea, sugar bean and velvet bean. They also tried intercropping with two legumes on one of the plots. Then they compared all those options to growing maize alone.

“Season by season the soil on each of the trial plots has got darker and my maize healthier,” describes Musafari. “Rains used to come and wash away the soil, but now we don’t plow or dig holes, so the soil is not being washed away; it holds the water.”

“I really like how the legumes have reduced the weeds. Before we had a major problem with witchweed, which is common in poor soils, but now it’s gone,” he adds.

Since the first season of the trial, Musafari’s maize yields have almost tripled. The first season his maize harvested 11 bags, or half a ton, and two seasons later it has increased to 32 bags, or 1.5 tons.

Musafari’s wife Eveline has also been convinced about the benefits of intercropping, expressing the family now wants to extend it to the whole farm. “Intercropping has more advantages than just growing maize. We get different types of food on the same space. We have more to eat and more to sell,” she says.

The family prefers intercropping with jack bean and lablab. Even though they were among the hardest legumes to sell, they improved the soil the most. They also mature at the same time as their maize, so they save labor as they only have to harvest once.

The benefits gained during intercropping have influenced farmers to adopt it as part of their farming practices at most of our trial sites across southern Africa, CRS’s Heinrich says.

“Immediate benefits, such as reduced weeding labor and legume cash crops that farmers can sell off quick, provide a good incentive for adoption,” he adds.

Honest and Eveline Musafari with extension worker, Memory Chipinguzi. Neighbors have noticed the intercropping trials on the Musafari’s farm and are beginning to adopt the practice to gain similar benefits. (Photo: Matthew O’Leary/CIMMYT)
Honest and Eveline Musafari with extension worker, Memory Chipinguzi. Neighbors have noticed the intercropping trials on the Musafari’s farm and are beginning to adopt the practice to gain similar benefits. (Photo: Matthew O’Leary/CIMMYT)

Climate-resilient farming systems for Africa

Food security is at the heart of Africa’s development agenda. However, climate change is threatening the Malabo Commitment to end hunger in the continent by 2025. Temperatures are increasing: the past three decades have been the warmest on record, according to the International Panel on Climate Change.

Hotter climates, more dry spells and erratic rainfall are a major concern to farmers in sub-Saharan Africa, where over half of maize is grown in rain-fed farming without irrigation.

The majority of African farmers are smallholders who cultivate less than 2 hectares, explains Thierfelder. If they are to meet the food demand of a population set to almost double by 2050, bringing it to over 2 billion people while overcoming multiple challenges, they need much more productive and climate-resilient cropping systems.

New research identifies that the defining principles of conservation agriculture alone are not enough to shield farmers from the impacts of climate change. Complementary practices are required to make climate-resilient farming systems more functional for smallholder farmers in the short and long term, he warns.

“Intercropping with legumes is one complementary practice which can help building healthy soils that stand up to erratic weather,” says Thierfelder. “CIMMYT promotes climate-resilient cropping systems that are tailored to farmers’ needs,” he emphasizes.

“To sustainably intensify farms, growers need to implement a variety of options including intercropping, using improved crop varieties resistant to heat and drought and efficient planting using mechanization along with the principles of conservation agriculture to obtain the best results.”

New publications: Toxin-producing fungal strains can now be detected in maize field soils with a new technique

A novel approach allows the detection of aflatoxin-producing fungi in maize fields. A new study explains the technique and how it was tested. “Detection of Aflatoxigenic and Atoxigenic Mexican Aspergillus Strains by the Dichlorvos–Ammonia (DV–AM) Method” was developed in collaboration between scientists from the International Maize and Wheat Improvement Center (CIMMYT), the Japanese National Agriculture and Food Organization (NARO) and Fukui University of Technology, funded in part by the CGIAR Research Program on Maize (MAIZE).

Aflatoxins are harmful compounds produced by the fungi Aspergillus flavus, which can be found in the soil, plants and grain of a variety of cereals and commodities including maize, nuts, cottonseed, spices and dried fruit. The toxic carcinogenic qualities of aflatoxins pose serious health hazards to humans and animals when contaminated crops are ingested. These health risks include cancers of the liver and gallbladder, stunted development in children, premature births and abnormal fetal development.

Not all strains of A. flavus produce aflatoxins however, so it is important to be able to detect and distinguish between A. flavus strains that are benign (atoxigenic) and those that produce dangerous toxins (aflatoxigenic). Current methods of detection are often complicated by the fact that the fungal strains display very similar physiological and molecular traits, thus a new approach is required.

In the study, a novel approach to detect and distinguish A. flavus strains was tested. Using soil samples from a CIMMYT experimental maize field in Mexico, fungal isolates were chemically treated in-line with a method recently developed in Japan, resulting in a color change indicative of toxicity. The method was found to be effective and accurate in the detection of the aflatoxigenic strains of the fungus.

This study is foundational work in the development of a simple, cost-effective and efficient method of detecting aflatoxigenic strains of A. flavus, which will help inform growers about the potential aflatoxin contamination of their crops. This is of particular importance in the developing world, where the resources for effective control of the fungus are often lacking.

To read the original study, “Detection of Aflatoxigenic and Atoxigenic Mexican Aspergillus Strains by the Dichlorvos–Ammonia (DV–AM) Method”, please click here.

Original citation: Kushiro, M.; Hatabayashi, H.; Yabe, K.; Loladze, A. Detection of Aflatoxigenic and Atoxigenic Mexican Aspergillus Strains by the Dichlorvos–Ammonia (DV–AM) Method. Toxins 2018, 10, 263.

This article was originally published on the website of the CGIAR Research Program on Maize.

Maize ear infected with Aspergillus flavus. (Photo: Maize Pathology Laboratory/CIMMYT)
Maize ear infected with Aspergillus flavus. (Photo: Maize Pathology Laboratory/CIMMYT)

Check out other recent publications by CIMMYT researchers below:

  1. Genetic analysis of tropical midaltitude-adapted maize populations under stress and nonstress conditions. 2018. Makumbi, D., Assanga, S., Diallo, A., Magorokosho, C., Asea, G., Regasa, M.W., Bänziger, M. In: Crop Science v. 58, no. 4, p. 1492-1507.
  2. Interactions among genes Sr2/Yr30, Lr34/Yr18/Sr57 and Lr68 confer enhanced adult plant resistance to rust diseases in common wheat (Triticum aestivum L.) line ‘Arula’. 2018.  Randhawa, M.S., Caixia Lan, Basnet, B.R., Bhavani, S., Huerta-Espino, J., Forrest, K.L., Hayden, M., Singh, R.P. In: Australian Journal of Crop Science v. 12, no. 6, p. 1023-1033.
  3. Practical breeding strategies to improve resistance to Septoria tritici blotch of wheat. 2018. Tabib Ghaffary, S.M., Chawade, A., Singh, P.K. In: Euphytica v. 214, art. 122.
  4. Sashaydiall : A SAS program for hayman’s diallel analysis. 2018. Makumbi, D., Alvarado Beltrán, G., Crossa, J., Burgueño, J. In: Crop Science v. 58, no. 4, p. 1605-1615.
  5. Soil bacterial diversity under conservation agriculture-based cereal systems in indo-gangetic plains. 2018. Choudhary, M., Sharma, P.C., Jat, H. S., Dash, A., Rajashekar, B., McDonald, A., Jat, M.L.  In: 3 Biotech v. 8, art. 304.

Preserving native maize and culture in Mexico

Felipa Martinez shows off some of her family’s maize from last year’s harvest. Photo: Matthew O’Leary

Felipa Martinez, an indigenous Mexican grandmother, grins as she shows off a bag bulging with maize cobs saved from last harvest season. With her family, she managed to farm enough maize for the year despite the increasing pressure brought by climate change.

Felipa’s grin shows satisfaction. Her main concern is her family, the healthy harvest lets her feed them without worry and sell the little left over to cover utilities.

“When our crops produce a good harvest I am happy because we don’t have to spend our money on food. We can make our own tortillas and tostadas,” she said.

Her family belongs to the Chatino indigenous community and lives in the small town of Santiago Yaitepec in humid southern Oaxaca. They are from one of eleven marginalized indigenous communities throughout the state involved in a participatory breeding project with the International Maize and Wheat Improvement Center (CIMMYT) to naturally improve the quality and preserve the biodiversity of native maize.

These indigenous farmers are custodians of maize biodiversity, growing seeds passed down over generations. Their maize varieties represent a portion of the diversity found in the 59 native Mexican races of maize, or landraces, which first developed from wild grasses at the hands of their ancestors. These different types of maize diversified through generations of selective breeding, adapting to the environment, climate and cultural needs of the different communities.

In recent years, a good harvest has become increasingly unreliable, as the impacts of climate change, such as erratic rainfall and the proliferation of pests and disease, have begun to challenge native maize varieties. Rural poor and smallholder farmers, like Martinez and her family, are among the hardest hit by the mounting impacts of climate change, according to the Food and Agriculture Organization of the United Nations.

These farmers and their ancestors have thousands of years of experience selecting and breeding maize to meet their environment. However, climate change is at times outpacing their selection methods, said CIMMYT landrace improvement coordinator Martha Willcox, who works with the community and coordinates the participatory breeding project. Through the initiative, the indigenous communities work together with professional maize breeders to continuously improve and conserve their native maize.

Despite numerous challenges, farmers in the region are unwilling to give up their maize for other varieties. “The native maize, my maize grows best here, it yields well in our environment. The maize is sweeter, it is heavier,” said Don Modesto Suarez, Felipa’s husband. “This maize has been grown by our grandfathers and this is why I will not change it.”

Una mujer de la comunidad Chatino prepara tortillas muy grandes de maíz criollo que son muy apreciadas en los mercados locales. Foto: Matthew O’Leary

This is because a community’s native maize varieties are adapted to their specific microclimate, such as elevation and weather patterns, and therefore may perform better or be more resistant to local pests and diseases than other maize varieties. They may also have specific characteristics prized for local culinary traditions — for example, in Santiago Yaitepec the native maize varieties have a specific type of starch that allows for the creation of extra-large tortillas and tostadas that are in high demand in local markets.

Other varieties may not meet farmers’ specific needs or climate, and many families do not want to give up their cultural attachment to native maize, said Flavio Aragon, a genetic resources researcher at the Mexican National Institute for Forestry, Agriculture and Livestock Research (INIFAP) who collaborates with Willcox.

CIMMYT and INIFAP launched the four-year participatory plant breeding project to understand marginalized communities’ unique makeup and needs – including maize type, local climates, farming practices, diseases and culture – and include farmers in breeding maize to suit these needs.

“Our aim is to get the most out of the unique traits in the native maize found in the farmer’s fields. To preserve and use it to build resistance and strength without losing the authenticity,” said Aragon.

“When we involve farmers in the process of selection, they are watching what we are doing and they are learning techniques,” he said. “Not only about the process of genetic selection in breeding but also sustainable farming practices and this makes it easier for farmers to adopt the maize that they have worked alongside breeders to improve through the project.”

Suarez said he appreciates the help, “We are learning how to improve our maize and identify diseases. I hope more farmers in the community join in and grow with us,” he said.

When disease strikes

Chatino men stand in a maize field in Santiago Yaitepec, Oaxaca, Mexico. Tar spot complex threatened harvests, but work in participatory breeding with CIMMYT has helped local communities to improve their native maize without loosing preferred traits. (Photo: Matthew O'Leary)
Chatino men stand in a maize field in Santiago Yaitepec, Oaxaca, Mexico. Tar spot complex threatened harvests, but work in participatory breeding with CIMMYT has helped local communities to improve their native maize without loosing preferred traits. (Photo: Matthew O’Leary)

Changes in weather patterns due to climate change are making it hard for farmers to know when to plant their crops to avoid serious disease. Now, a fungal disease known as tar spot complex, or TSC, is increasingly taking hold of maize crops, destroying harvests and threatening local food security, said Willcox. TSC resistance is one key trait farmers want to include in the participatory breeding.

Named for the black spots that cover infected plants, TSC causes leaves to die prematurely, weakening the plant and preventing the ears from developing fully, cutting yields by up to 50 percent or more in extreme cases.

Caused by a combination of three fungal infections, the disease occurs most often in cool and humid areas across southern Mexico, Central America and into South America. The disease is beginning to spread, possibly due to climate change, evolving pathogens and introduction of susceptible maize varieties.

“Our maize used to grow very well here, but then this disease came and now our maize doesn’t grow as well,” said Suarez. “For this reason we started to look for maize that we could exchange with our neighbors.”

A traditional breeding method for indigenous farmers is to see what works in fields of neighboring farmers and test it in their own, Willcox said.

Taking the search to the next level, Willcox turned to the CIMMYT Maize Germplasm Bank, which holds over 7000 native maize seed types collected from indigenous farmers. She tested nearly a thousand accessions in search of TSC resistance. A tedious task that saw her rate the different varieties on how they handled the disease in the field. However, the effort paid off with her team discovering two varieties that stood up to the disease. One variety, Oaxaca 280, originated from just a few hours north of where the Suarez family lives.

Farmer Modesto Suarez (left) and neighbors were originally cautious to plant Oaxaca 280 in their fields, but were pleased with the results. (Photo: Matthew O’Leary)
Farmer Modesto Suarez (left) and neighbors were originally cautious to plant Oaxaca 280 in their fields, but were pleased with the results. (Photo: Matthew O’Leary)

After testing Oaxaca 280 in their fields the farmers were impressed with the results and have now begun to include the variety in their breeding.

“Oaxaca 280 is a landrace – something from Mexico – and crossing this with the community’s maize gives 100 percent unimproved material that is from Oaxaca very close to their own,” said Willcox. “It is really a farmer to farmer exchange of resistance from another area of Oaxaca to this landrace here.”

“The goal is to make it as close as it can be to what the farmer currently has and to conserve the characteristics valued by farmers while improving specific problems that the farmers request help with, so that it is still similar to their native varieties and they accept it,” Aragon said.

Expanding for impact

Willcox and colleagues throughout Mexico seek to expand the participatory breeding project nationwide in a bid to preserve maize biodiversity and support rural communities.

“If you take away their native maize you take away a huge portion of the culture that holds these communities together,” said Willcox. Participatory breeding in marginalized communities preserves maize diversity and builds rural opportunities in areas that are hotbeds for migration to the United States.

“A lack of opportunities leads to migration out of Mexico to find work in other places, a strong agricultural sector means strong rural opportunities,” she said.

To further economic opportunities in the communities, these researchers have been connecting farmers with restaurant owners in Mexico City and the United States to export surplus grain and support livelihoods. A taste for high-quality Mexican food has created a small but growing market for the native maize varieties.

The next generation: The granddaughter of Felipa Martinez and Modesto Suarez stands in her grandparent's maize field. (Photo: Matthew O'Leary)
The next generation: The granddaughter of Felipa Martinez and Modesto Suarez stands in her grandparent’s maize field. (Photo: Matthew O’Leary)

Native maize hold the building blocks for climate-smart crops

Native maize varieties show remarkable diversity and climate resilience that grow in a range from arid to humid environments, said Willcox. The genetic traits found in this diversity are the building blocks that can be used to develop varieties suitable for the changing crop environments predicted for 2050.

“There is a lot of reasoning that goes into the way that these farmers farm the land, the way they decide on what they select for,” said Willcox. “This has been going on for years and has been passed down through generations. For this reason, they have maize of such high quality with resistance to local challenges, genetic traits that now can be used to create strong varieties to help farmers in Mexico and around the world.”

It is key to analyze the genetic variability of native maize, and support the family farmers who conserve it in their fields, she added. This biodiversity still sown and selected throughout diverse microclimates of Mexico holds the traits we need to protect our food supplies.

To watch a video on CIMMYT’s work in this community, please click here.

This work has been conducted as part of the CIMMYT-led MasAgro project in collaboration with INIFAP, and supported by Mexico’s Department of Agriculture, Livestock, Rural Development, Fisheries and Food (SAGARPA) and the CGIAR Research Program MAIZE

 

Agriculture can help the world meet climate change emission targets

Precision levelers are climate-smart machines equipped with laser-guided drag buckets to level fields so water flows evenly into soil, rather than running off or collecting in uneven land. This allows much more efficient water use and saves energy through reduced irrigation pumping, compared to traditional land leveling which uses animal-powered scrapers and boards or tractors. It also facilitates uniformity in seed placement and reduces the loss of fertilizer from runoff, raising yields. (Photo: CIMMYT)
Precision levelers are climate-smart machines equipped with laser-guided drag buckets to level fields so water flows evenly into soil, rather than running off or collecting in uneven land. This allows much more efficient water use and saves energy through reduced irrigation pumping, compared to traditional land leveling which uses animal-powered scrapers and boards or tractors. It also facilitates uniformity in seed placement and reduces the loss of fertilizer from runoff, raising yields. (Photo: CIMMYT)

As world leaders meet in Paris this week to agree on greenhouse gas emission targets, we in the field of agricultural research have a powerful contribution to make, by producing both robust estimates of the possible effects of climate change on food security, and realistic assessments of the options available or that could be developed to reduce agriculture’s contribution to greenhouse gas emissions.

Agriculture is estimated to be responsible for about a fifth of global greenhouse gas emissions, and this share is increasing most rapidly in many developing countries; it may even increase as fossil fuels become scarcer and phased out in other sectors.

The solution being put forward today is climate-smart agriculture (CSA), which involves three components: adaptation, mitigation, and increased productivity. Adaptation is essential to cope with the impacts that cannot be avoided and to maintain and increase the global food supply in the face of resource constraints; mitigation can lessen but not prevent future climate changes.

Though CSA has been held up as an answer to the challenges presented by climate change, some would argue that it is no more than a set of agricultural best practices. Indeed, this is what lies at the heart of the approach.

In addition to making agriculture more efficient and resilient, the overall purpose remains to sustainably increase farm productivity and profitability for farmers. This is why over the last few years we have begun talking about the ‘triple win’ of CSA: enhanced food security, adaptation, and mitigation. But those who dismiss CSA as mere best practice ignore the value of seeing through the climate change lens, and guiding research to respond to expected future challenges.

To begin with, crop performance simulation and modeling, in combination with experimentation, has an important role to play in developing CSA strategies for future climates.

In a publication titled “Adapting maize production to climate change in sub-Saharan Africa,” several CIMMYT scientists concluded that temperatures in sub-Saharan Africa will likely rise by 2.1°C by 2050 based on 19 climate change projections. This is anticipated to have an extreme impact for farmers in many environments. Because it takes a long time to develop and then deploy adaptation strategies on a large scale, they warned, there can be no delay in our work.

This explains why CIMMYT is taking the initiative in this area, seeking support to develop advanced international breeding platforms to address the difficulty of developing drought-tolerant wheat, or bringing massive quantities of drought- and heat-tolerant maize to farmers through private sector partners in Africa and Asia.

Our insights into the causes and impacts of climate change lead us to important research questions. For example, how can farmers adopt practices that reduce the greenhouse gas footprint of agriculture while improving yield and resilience?

Colleagues at CIMMYT have challenged the idea that the practice of no-till agriculture (which does not disturb the soil and allows organic matter to accumulate) contributes significantly to carbon sequestration. I think it is important that we, as scientists, explore the truth and be realistic about where opportunities for mitigation in agriculture lie, despite our desire to present major solutions. It is also important to take action where we can have the greatest impact, for example by improving the efficiency of nitrogen fertilizer use.

Nitrous oxide emissions from agriculture have a climate change potential almost 300 times greater than carbon dioxide, and account for about 7% of the total greenhouse gas emissions of China. Improved nutrient management could reduce agricultural greenhouse gas emissions by the equivalent of 325 Mt of carbon dioxide in 2030. Overall, supply-side efficiency measures could reduce total agricultural emissions by 30%.

Some practices, such as laser land leveling, fall into both the adaptation and mitigation categories. Preparing the land in this way increases yields while reducing irrigation costs, the amount of water used, nutrients leached into the environment, and emissions from diesel-powered irrigation pumps.

Findings such as this offer real hope of reducing the severity of climate change in the future, and help us build a case for more investment in critical areas of agricultural research.

For climate-smart agriculture, the challenge of feeding more people and reducing emissions and environmental impact is not a contradiction but a synergy. We are improving our ability to predict the challenges of climate change, and proving that it is possible to greatly reduce agricultural emissions and contribute to global emission goals.

To face challenges such as climate change, we need high quality multi-disciplinary science combined with approaches to address problems at the complex systems level. Since my involvement in early large-scale studies, such as Modeling the Impact of Climate Change on Rice Production in Asia (CABI/IRRI, 1993), I am pleased to see that so much progress has been made in this regard and encouraged that our research is contributing to greater awareness of this vital issue and solutions to address it.