Chapters authored
Bringing Climate Smart Agriculture to Scale: Experiences from the Water Productivity Project in East and Central Africa
Since 2010, six research organizations in the region have implemented a regional project that sought to combat food insecurity, poverty and climate change by up-scaling Climate-Smart Agriculture (CSA) technologies across farms and landscapes using the Climate Smart Landscape (CSL) approach. Several CSA technologies were evaluated and promoted across landscapes using this approach with remarkable success. Maize yields in Kenya rose from 0.5 to 3.2 t ha-1, resulting in over 90% of the watershed communities being food secure. In Madagascar, rice yields increased from 2 to 4 t ha-1 whilst onion yields increased from 10 to 25 t ha-1, resulting in watershed communities being 60% food-secure. In Eritrea, sorghum yields increased from 0.6 to 2 t ha-1. Farmers in Ethiopia earned US$10,749 from the sale of pasture whilst in Madagascar, watershed communities earned additional income of about US$2500/ha/year from the sale of onions and potatoes during off-season. Adoption levels of various CSA technologies rose from less than 30% to over 100% across the participating countries, resulting in rehabilitation of huge tracts of degraded land. In a nutshell, the potential for CSL in the region is huge and if exploited could significantly improve our economies, lives and environment.
Part of the book: Climate Resilient Agriculture
Fertilizer Use Issues for Smallholder Agriculture in Tropical Africa
Fertilizer is an essential input for wide-scale sustainable intensification of crop productivity in tropical Africa, but its use by smallholders is often financially constrained. Four fertilizer use issues are addressed. Smallholders need high net returns from their investments, with acceptable risk, which can be achieved with good crop-nutrient-rate choices made in consideration of the farmer’s financial and agronomic context. Soil acidification, which is affected by crop N supply, is best managed with the use of slightly more acidifying but less costly common N fertilizer, e.g., urea, coupled with lime use compared with the use of more costly but less acidifying N fertilizer such as calcium ammonium nitrate. This chapter addresses the feasibility of tailored fertilizer blends for maximizing farmer profit with respect to the nutrient supply cost, the need for flexibility in nutrient application according to the farmer’s context, and the weak justification for tailoring blends based on soil test results. The use of a well-formulated blends is justified in some cases, e.g., for some crops in Rwanda, but the supply of blends does not justify restricting the supply of common fertilizers. Farmers need to be aware that unregulated nontraditional products very often fail to provide the claimed benefits. Fertilizer use, sometimes with timely lime application, can be highly profitable with modest risk with good crop-nutrient-rate choices, adequate free-market fertilizer supply, and avoiding products with unsubstantiated claims.
Part of the book: Sustainable Crop Production
Impact of Climate Change on Maize and Pigeonpea Yields in Semi-Arid Kenya
The objective of this study was to assess the impact of climate change on intercrops of maize and improved pigeonpea varieties developed. Future climate data for Katumani were downscaled from the National Meteorological Research Centre (CNRM) and Commonwealth Scientific and Industrial Research Organization (CSIRO) climate models using the Statistical Downscaling Model (SDSM) version 4.2. Both models predicted that Katumani will be warmer by 2°C and wetter by 11% by 2100. Agricultural Production Systems Simulator (APSIM) model version 7.3 was used to assess the impact of both increase in temperature and rainfall on maize and pigeonpea yield in Katumani. Maize crop will increase by 141–-150% and 10–-23 % in 2050 and 2100, respectively. Intercropping maize with pigeonpea will give mixed maize yield results. Pigeonpea yields will decline by 10–20 and 4–9% by 2100 under CSIRO and CNRM models, respectively. Intercropping short and medium duration pigeonpea varieties with maize will reduce pigeonpea yields by 60–80 and 70–90% under the CSIRO and CNRM model, respectively. There is a need to develop heat and waterlogging-tolerant pigeonpea varieties to help farmers adapt to climate change and to protect the huge pigeonpea export market currently enjoyed by Kenya.
Part of the book: Environmental Issues and Sustainable Development