564 research outputs found

    The conundrum of conservation agriculture and livelihoods in Southern Africa

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    Low crop productivity, food insecurity, hunger and malnutrition; inadequate farming knowledge and skills, implements and inputs are characteristic of smallholder agriculture in Southern Africa. Many researchers argue that conservation agriculture can guarantee higher crop productivity, food security, improved livelihoods and environmental protection, better than the unsustainable traditional systems of slash and burn practices. In this paper, we present the results of a meta-analysis of over 40 academic publications to review conservation agricultureā€™s role in influencing desired livelihood outcomes in Southern Africa. We conclude that the effectiveness of conservation agriculture towards better livelihood outcomes in Southern Africa remains debatable, especially when supportive government policies are lacking

    Managing soil fertility diversity to enhance resource use efficiencies in smallholder farming systems: a case from Murewa District, Zimbabwe

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    Smallholder farms in sub-Saharan African exhibit substantial heterogeneity in soil fertility, and nutrient resource allocation strategies that address this variability are required to increase nutrient use efficiencies. We applied the Field-scale resource Interactions, use Efficiencies and Long-term soil fertility Development (FIELD) model to explore consequences of various manure and fertilizer application strategies on crop productivity and soil organic carbon (SOC) dynamics on farms varying in resource endowment in a case study village in Murewa District, Zimbabwe. FIELD simulated a rapid decline in SOC and maize yields when native woodlands were cleared for maize cultivation without fertilizer inputs coupled with removal of crop residues. Applications of 10 t manure ha-1 year-1 for 10 years were required to restore maize productivity to the yields attainable under native woodland. Long-term application of manure at 5 and 3 t ha-1 resulted in SOC contents comparable to zones of high and medium soil fertility observed on farms of wealthy cattle owners. Targeting manure application to restore SOC to 50ā€“60% of contents under native woodlands was sufficient to increase productivity to 90% of attainable yields. Short-term increases in crop productivity achieved by reallocating manure to less fertile fields were short-lived on sandy soils. Preventing degradation of the soils under intensive cultivation is difficult, particularly in low input farming systems, and attention should be paid to judicious use of the limited nutrient resources to maintain a degree of soil fertility that supports good crop response to fertilizer applicatio
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