Climate Change and Dryland Stresses
Photo ICRISAT
Water stress often drastically limits crop yields in the drylands.
 
 

One third of the world's population live in drylands, facing huge stresses such as repetitive droughts and poor soil fertility. Climate change will further  worsen the situation. There is an urgent need to provide adapted and climate smart solutions to millions of smallholder farmers to improve their food security and resilience to such dryland stresses.

>12 million ha The arable land degraded by desertification  every year. If this trend continues, the equivalent of US arable land will disappear in less than 15 years.

1/3 Extent of the world population that lives in the drylands, regions which are the worst affected by land degradation

5% -Decrease in plant growing period in the tropics due to global warming by 2050 (CCAFS).


Living with risk and uncertainty

Drylands represent 40% of the world`s land area. Over one third of the world`s population (2.5 billion people) live in dryland regions,with a third depending on agriculture.

Frequent drought and environmental degradation are widespread, worsening an already critical poverty and food/nutrition insecurity situation. 644 million people living in drylands are considered as the poorest of the poor. They do not have many livelihood options apart from rain fed agriculture, being very vulnerable to multiple dryland stresses, including  drought and flooding, results of low and erratic rainfall, rampant desertification and land degradation, highly variable climate and low soil fertility (Sahelien soils for instance are very low in phosphorus and organic matter).

Climate change predictions point to a warmer world within the next 50 years, a trend that is increasingly being supported by ‘on-the-ground' measurements. Climate change is expected to increase the scale of dryland stresses even though the impact of rising temperatures on rainfall distribution patterns in the SAT of Africa and Asia remains far less certain.

 According to the CCAFS climate hotspots report, high temperature stress (above 30°C) will be widespread by 2050 reducing the growing period in the tropical regions by 5%. Farmers "will experience a change in growing conditions that will require adaptation to current agricultural systems." As many farmers practice rain-fed agriculture and do not have access to irrigation means, dropping below 120 days of growing period will prevent them cultivating certain water intensive crops. A decrease in reliable crop growing days to critical levels would mean crop cultivation might become too risky to pursue as a major livelihood strategy in a larger number of places across the global tropics, including West and East Africa.

Building the resilience of dryland farming communities

  • Understanding the impact of dryland stresses on smallholder agriculture

Understanding the scope of dryland stresses and how agriculture is affected enables us to understand the impact on smallholder farming. Village Level Studies help illustrate how smallholder farm households deal with drought and other shocks.

Crop simulation models examine the consequences of different crop management actions for coping with drought and adapting to climate change in drylands. They help identify high-impact adaptive strategies at farm level, and provide useful insights, such as predicting future aflatoxin outbreaks, to develop appropriate adaptation policies.  For instance,  the Agricultural Model Intercomparison and Improvement Project, or AgMIP,   aims to assess climate impacts on regional and global food security now and in the future, integrating the findings of various crop, climate and farm management models.

  • Growing adapted crops

Certain crops are better adapted to the harsh and variable climate of drylands. Nutri-resilient cereals like millets and sorghum have greater water efficiency than maize and rice. Certain grain legumes such as groundnut, chickpea  and pigeonpea can thrive in poor soil and drought conditions.  

Crop physiology research helps to understand the plant mechanisms in response to the stresses. For instance, how a plant reacts to a drought or high temperatures during the growing or the flowering stage? Why certain seedlings can grow in a soil poor in phosphorus or other soil nutrients, while others die? This high science then helps define plant breeding strategies to develop crop varieties better equipped to face dryland stresses. By studying stress-protecting proteins like aquaporines, early maturity, differences in root systems, or other phenotypes, we can indicate what makes sense for drought tolerance selection for instance.

  • Building resilience - a systems perspective

As we saw above, some crops better tolerate dryland stresses than others but they may not have a high market value. So many farmers will grow other crops with a better market value despite the risk of crop failure. We need to provide the right incentives (eg policies, market outlets, access to improved seeds) for farmer to grow crops tolerant to drought and other dryland stresses. 

Solutions to help communities cope with dryland stresses and adapt to climate change should be developed and scaled up. ICRISAT is working with local, national and international partners on initiatives that revitalise soils and conserve water, enabling communities be more drought resilient, sustain good yields and improve their food security from otherwise degraded or soon to become degraded lands.

The approach of bioreclamation of degraded lands shows how women's groups could revitalize barren lands by using simple water and soil conservation techniques, such as zai pits (small holes enriched with compost), to plant drought-tolerant trees and crops, and applying small amounts of fertiliser to the plant root, a technique known as microdosing.

As Kothapally watershed community management shows, investing in water conservation and rainfall harvesting (eg  rock bunds and other silt stopper structures, and use of vermicompost to increase organic matter in the soil) can significantly reduce soil erosion and water run-off and increase soil water holding capacity.

Crop diversity and a more diversified farming system helps to better manage the climate risks and can generate new income sources. The CERLIVTREES project  investigates Crop-tree-livestock synergies and its trade-offs (eg animal feed or incorporate in the soil, what is the better use of straw residues?) as solutions to increase incomes while enriching and buffering water and nutrient supplies, protecting soils and moderating microclimates.

Access to appropriate irrigation means, like the African Market Garden, for the majority of farmers practicing rain-fed agriculture will increase their productivity and resilience.

Agricultural market risks and shocks can be reduced through promoting access to key services such as insurance and finance.

  • Building farmer adaptation capacity and providing decision-making tools

Farming communities of the SAT need the right information and training to cope better with current season-to-season climate variability.

Climate information in the form of seasonal forecasts can help farmers take advantage of good seasons and mitigate against bad seasons. Climate Field Schools in Zimbabwe for instance train farmers about practical implications of climate variability and building appropriate coping and adaptation strategies such as using crop diversity to reduce the risk of crop losses during prolonged drought.

Mapping drought risks , testing soil nutrient deficiencies, or other farmer-friendly communication and knowledge tools, backed up with the right extension strategy help farmers better understand the benefits of investing in stress-resistant crops so that they move towards resilient crops.

Farmers can test climate change adaptation strategies such as greater crop diversity by exchanging experience with a "2 degrees hotter climate" twin community.  

In drylands, the reality is that farmers will always face important stresses which will worsen with global warming. Agriculture policies should not only invest in risk-reducing interventions, but also provide and improve access to safety nets (eg rainfall crop insurance, food distribution systems, input vouchers) so that farmers can better recover from the next drought or other shock.

Drought risk map : better informed, better crop choices.
Pairing "climate twins" in Eastern Africa for communities to test adaptation strategies for  their future climate (CALESA).
Photo: ICRISAT
Desertification is accelerating in dryland regions due in part to repetitive drought, unsustainable soil management and overgrazing.
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Photo: ICRISAT
We must make up ground in the fight against desertification.

Sorghum and millets have greater water efficiency than maize.

Photo: ICRISAT

Lysimeter facility at ICRISAT - crop physiology research for better adaption to dryland stresses.

Photo: ICRISAT

Fertilizer microdosing - appropriate technologies for greater productivity on dryland farms.

Encourage farmers to grow drought-tolerant crops: small seed packs and market