Animal manure provides plant nutrients and also affects soil nutrient availability, pH buffering and soil physical properties through its contribution to soil organic matter pools. However, the quality and quantity of manure are often low on smallholder farms in sub-Saharan Africa and the initial effect of manuring on crop yield may be small or even negative. In a two-factorial experiment over four seasons in southern Rwanda, the fertiliser value to a maize crop of manures produced by cattle fed a basal diet of only Chloris gayana grass or a mixed C. gayana-Acacia angustissima diet was compared with that of NPK 17−17−17 and no fertiliser. The potential liming effect of the manures was also evaluated through inclusion (or not) of travertine as the second factor. All amendments were applied only to maize planting holes. The crop failed in season 1 due to drought, but manure application (5 t ha⁻¹) approximately doubled maize yield compared with the unfertilised control during seasons 2–4, while NPK (70 kg N ha⁻¹) increased yield by 3- to 4-fold, with corresponding improvements in crop performance indicators. The mixed diet increased manure quality and maize yield compared with the grass diet in season 4. Liming showed a consistent tendency to improve crop performance indicators and yield, but significant differences were only identified in some cases, possibly because the pH increase was small. The results suggest that in regions where manure availability is limiting, application of reduced rates only to planting holes may be an efficient technology. Enhanced animal feed can result in higher quality manure, and ultimately increase crop yield, if nutrient losses during manure handling and storage can be limited.

动物粪便不仅提供植物养分，还通过对土壤有机质池的贡献来影响土壤养分的利用率，pH缓冲和土壤物理性质。但是，撒哈拉以南非洲小农户的粪便质量和数量通常很低，而且粪便对作物产量的最初影响可能很小，甚至是负面的。在卢旺达南部四个季节进行的两次因子试验中，饲喂仅饲喂克洛里斯·加纳纳草或混合加达纳-金合欢的基础日粮的牛对玉米作物的肥料价值饮食与NPK 17-17-17相比，没有施肥。还通过包含（或不包含）石灰华作为第二因素来评估粪便的潜在石灰效应。所有修正案仅适用于玉米播种孔。在第1季，由于干旱，农作物歉收，但在2-4季，与未施肥的对照相比，施用肥料（5 t ha ^-1）的玉米产量几乎翻了一番，而NPK（70 kg N ha ^-1）将产量提高了3到4倍，并相应提高了作物性能指标。与第4季的草食相比，混合饮食提高了粪肥质量和玉米产量。黎明显示出持续改善作物性能指标和产量的趋势，但是只有在某些情况下才发现显着差异，这可能是因为pH值升高很小。结果表明，在肥料利用率有限的地区，仅将种植率降低用于种植孔可能是一种有效的技术。如果可以限制粪便处理和储存过程中的养分流失，增强的动物饲料可以提高粪便质量，并最终提高作物产量。