Water management and technology can stave off worst effects of climate change
Tuesday January 04 2022
Climate change, which is expressed in terms of drought, floods, and changing rainfall patterns and increased variability, is expected to hit sub-Saharan Africa most.
Africa experienced a 30 per cent increase in the frequency and duration of drought events since the year 2000. In 2019, the climate crisis affected more than 33 million people across east and southern African countries in food insecurity as a result of floods, landslides, drought, and cyclones.
Africa is vulnerable because the economies of its states are largely based on weather-sensitive crop-livestock systems, and also due to the low adaptation capacity of communities to threats of climate change. The adaptation is strongly linked to access and use of improved technologies and practices to develop resilient systems.
The experience of AGRA (Alliance for a Green Revolution in Africa), which has been spearheading agricultural transformation in Africa, shows that improving productivity, profitability, and adaptation to climate change could be concomitantly achieved by investments in a number of areas.
About 70 per cent of the land in sub-Saharan Africa (SSA) falls within arid or semi-arid farming systems, but only about 5 per cent has access to irrigation using water from rivers, streams, ground water, or rainwater harvesting. Only about 7 per cent of the arable land is irrigated in SSA against 40 per cent in Asia. Rainwater management could be practised anywhere in the continent by capturing, storing, and efficiently utilising rainwater from roofs and runoff.
Besides, small-scale irrigation from surface and groundwater can reduce farmers’ vulnerability to annual rainfall variability and associated climate risks.
The private sector needs to support expansion of small-scale irrigation in SSA by improving market opportunities, energy for water lifting, and access to irrigation water, including from shallow wells and groundwater.
Despite high demand for drought-resistant cultivars, farmers have limited access to high-yielding crop varieties. Availing the right crop to the right agroecology will ensure good crop yields and reduce the risk of crop failure due to drought and other climate-related calamities. High-yielding traditional African crops like sorghum and millet rarely reach farmers’ fields due to weak last-mile delivery systems.
Improved extension, including using village-based advisers, would help farmers get access to the appropriate varieties along with good agronomic advice.
About 65 per cent of agricultural crop land and 31 per cent of permanent grazing land in Africa is degraded. Only 17 kilogrammes of fertiliser is applied per hectare of arable land in Africa against 250 kilogrammes per hectare in Europe, hence aggravating soil fertility decline through nutrient mining.
Research shows that farming without fertiliser can cause up to 30 per cent and 60 per cent loss of soil organic matter after 12 years and 46 years, with crop yield declining from one tonne/ha to 300 kg/ha. While applying critical nutrients like phosphorus is important, adopting regenerative practices like composting and returning of crop residues to the soil will reduce fertiliser needs.
Our farmers need to adopt a combination of organic and blended mineral fertilisers, not only to improve productivity but also to improve the grain quality of crops through micronutrient enrichment. Since most soils in high-rainfall areas are acidic, it is also important to note that soils affected by soil acidity will not give good crop response to fertiliser application unless the soils are corrected by liming.
Mono-cropping is prone to climatic and market risks. Diverse types of fruit trees, vegetables, cash crops like coffee and cacao are grown in home gardens and produce forage for fattening small ruminants. These gardens are enriched by household refuse, manure, night soils, and other nutrient sources and produce up to 40 per cent of household food on about 15 per cent of the farmland.
They provide a wide range and steady supply of fresh produce throughout the year, potentially with considerable income and should be promoted throughout SSA. Research shows that home gardens in a small-scale setting could produce crops, trees, fodder, medicinal herbs, planting materials, and other products, with an income of about $3 per square metre per season.
In the era of climate change, lack of mechanisation exposes farmers to drought and invasion of pests and diseases. For instance, in drought-prone locations of Africa, a delay in planting of maize by a day could extend the maturity period of the crop by a month, exposing it to an end-of-season drought. The hoe-based plough cannot break the hard pan of the soil, preventing rainwater from infiltrating deeper to the root zone. Lack of mechanisation delays harvesting and proper storage, causing huge post-harvest losses, sometimes up to 30 to 50 per cent.
Lack of mechanisation
Most importantly, access to mechanisation is exacerbated by an underdeveloped ecosystem (equipment vendors, after sales services, loan and lease products, mechanics workshops, mechanisation as a service model) and the investment in the ecosystem is beyond the reach of individual farmers.
Farmers’ livelihoods largely depend on integrated crop and livestock systems. This is not only a risk management strategy (livestock serving as a savings account) but also critical for improved crop productivity due to the need for draught power, manure, efficient recycling of water and nutrients for improved soil fertility, economic risk mitigation and livelihood diversification.
Dairy, fattening, and poultry are becoming attractive investments around urban settings and would play an important role in the agricultural transformation of Africa. Moreover, most African drylands are livestock-based, and hence climate change adaptation and livelihood improvement cannot be achieved without improved management of the pastoral and agropastoral systems.
Aquaculture plays an important role in food security and profitability for Asian farmers, and should be integrated into the increasing rice fields of SSA. Unfortunately, integration of aquaculture has had a poor success rate.
Diverse land uses interact across landscapes to impact on the natural resource base that sustains agriculture and ecosystems. One of the major factors affecting agricultural productivity in SSA has been land degradation due to poor management and soil erosion. Land restoration by adopting soil and water conservation practices accompanied by innovations that bring short-term benefits in terms of fodder, fuelwood, water, and other resources would increase the tree cover, minimise erosion and improve watershed functions.
In the context of climate change, there is need for integrated watershed management that may include technological, social, policy and institutional interventions for land restoration while increasing productivity of water, nutrients, and labour for food security and environmental services. This also demands wider collaboration among key stakeholders at local and higher levels.
Dr Tilahum Amede is Head of Resilience, Climate and Soil Fertility at the Alliance for a Green Revolution in Africa; [email protected]