On farm testing of integrated nutrient management strategies in Eastern Uganda

This paper reports on a Participatory Learning and Action Research (PLAR) process that was initiated in three villages in eastern Uganda in September 1999 to enable small-scale farmers to reverse nutrient depletion of their soils profitably by increasing their capacity to develop, adapt and use integrated natural resource management strategies. The PLAR process was also used to improve the participatory skills and tools of research and extension personnel to support this process. The farming systems of the area were characterised for socio-economic and biophysical conditions that included social organisations, wealth categories, gender, crop, soil, agro forestry and livestock production. Farmers identified soil fertility constraints, their indicators, and causes of soil fertility decline, and suggested strategies to address the problem of soil fertility decline. Soil fertility management diversity among households indicated that most farmers were not carrying out any improved soil fertility management practices, despite previous research and dissemination in the area. Following the diagnosis stage and exposure visits to other farmer groups working on integrated soil fertility projects, the farmers designed 11 experiments for on-farm testing. One hundred and twenty farmers then chose, for participatory technology development, sub-sets of these 11 experiments, based on the major agricultural constraints and the potential solutions identified and prioritised by the farmers. Quantitative and qualitative results from the testing, farmer evaluation and adaptation, training, dissemination strategies and socio-economic implications of these technologies are discussed

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

Adapting African Agriculture to Climate Change: Transforming Rural Livelihoods

This book summarizes the evidence from different African countries about the local impacts of climate change, and how farmers are coping with current climate risks. The different contributors show how agricultural systems in developing countries are affected by climate changes and how communities prepare and adapt to these changes

Maize response to macronutrients and potential for profitability in sub-Saharan Africa

The final publication is available at Springer via http://dx.doi.org/10.1007/s10705-015-9717-2Sub-Saharan Africa (SSA) is plagued by low productivity and little research is available on the attainable responses and profitability to applied nutrients under variable environments. The objective of this study was to determine the attainable maize grain response to and potential of profitability of N, P and K application in SSA using boundary line approaches. Data from experiments conducted in SSA under AfSIS project (2009–2012) and from FAO trials database (1969–1996) in 15 countries and constituting over 375 different experimental locations and 6600 data points are used. Both response to fertilizer and value cost ratio (VCR) are highly variable and no more than 61 % cases for N, 43 % for P and 25 % for K attain VCR of 2 or more. Also, based on the recent AfSIS data, VCR exceeds 1 in just 67 % (N), 57 % (P) and 40 % (K) of the cases, even when best management practices are applied on a research farm, and interest rates are zero. Chances for profitability are highest when soil organic carbon is 1–2 % and control maize grain yield is 1–3 t ha−1 but also depends on relatively static soil properties (primarily texture and mineralogy) that are not under farmer control. We conclude that return on investment of macronutrient fertilizer is highly variable and can be substantially increased by helping farmers decide where to apply the fertilizers. Consequently, farmers need access to information on factors influencing economic returns of fertilizer use in order to make the right decisions

Resource flows and nutrient balances for crop and animal production in smallholder farming systems in Eastern Uganda

Resource flow models are useful tools that assist farmers in analysing their soil fertility management strategies and in planning, experimenting and adapting ways to improve the use of scarce local resources. Resource flows and farm nutrient balance studies were carried out in eastern Uganda to ascertain the movement of organic resources and nutrients in and out of the farm system during a participatory learning and action research (PLAR) process. The resource flows were transformed into nutrient flows and partial nutrient balances were calculated using the Resource Kit computer package. Results of a farmers soil fertility management classification at the start of the PLAR intervention in 1999 revealed that 3% of the farmers were good soil fertility managers (class I), 10% were average soil fertility managers (class II) and 87% were poor soil fertility managers (class III). The results indicate that the net farm nutrient balances in kg ha?1 per season for all the nutrients [nitrogen (N), phosphorus (P), and potassium (K)] were negative for both the good and the poor soil fertility managers. Class 1 farm balances irrespective of the season, were however more negative than those of class 3 farms. For the long rains seasons (LR 2000, 2001 and 2002), the average net farm nutrient balances for N, P, and K for class I farms were ?5.0, ?0.6 and ?8.0 kg ha?1 year?1, while for the short rains seasons (SR 2000 and 2001), the nutrient balances were ?3.5, ?0.5 and ?6.0 kg ha?1 year?1, respectively. For the class III farms, the average net farm nutrient balances for N, P, and K in the long rain seasons (LR 2000, 2001 and 2002) were ?3.3, ?0.3 and ?4.0 kg ha?1 year?1 while for the short rains seasons (SR 2000 and 2001), the nutrient balances were ?3.5, 0.5 and ?5.0 kg ha?1 year?1, respectively. Soil management interventions for these small-scale farmers should aim at reversing nutrient depletion with a focus on profitable management of the crop production system, which is the major cause of nutrient depletion