Combined use of lime, animal manure and inorganic fertilisers is effective in replenishing the fertility of degraded acid soils. However, many smallholder farmers lack access to sufficient amounts of these inputs to improve the fertility and reduce the aluminium toxicity of Ferralsols. Organic manures are available but often have low nutrient content, which limits their ability to supply nutrients to soils. In a two-factor field experiment over four seasons on an Anthropic Ferralsol in Southern Province, Rwanda, we assessed (i) the effect of cattle manure on soil properties at a reduced rate affordable to smallholder farmers compared with that of NPK fertiliser applied, with and without lime also at a reduced rate, and (ii) the effect of supplementing grass in a basal cattle diet with legume leaves on manure quality and its effect on soil properties. Manure from cattle fed only the grass Chloris gayana (grass-only manure) and from cattle fed C. gayana supplemented with Acacia angustissima leaves (grass+legume manure) was applied at 5 t dry matter ha-1 (25% of the recommended rate) at the beginning of each growing season. NPK was applied as split doses supplying a total rate of 70 kg N ha-1. Lime was applied annually at a rate of 2.0 t CaO ha-1, which was 25% of the rate required to neutralise total acidity at the site. All amendments were applied only to the soil surrounding the maize plants (planting stations), which is estimated at 25% of the plot area. Maize stover was left on plots after harvest and planting stations were retained over all growing seasons. All treatments altered soil properties at the planting stations. Lime generally increased pH but there was no significant difference between lime plus manure treatments and non-limed manure treatments. Soil organic carbon concentration and cation exchange capacity were higher in manure and NPK treatments than in non-fertilised treatments. The manure treatment increased soil water-holding capacity compared with the NPK and non-fertilised treatments. There was no significant difference in total N, Ca2+, Mg2+ and K+ between the NPK and manure treatments. Micro-dosing animal manure can thus replace mineral fertiliser plus lime for soil fertility replenishment in smallholder farming. Grass+legume manure contained higher concentrations of total N, Ca, Mg, K and Na than grass-only manure, but its effect on soil properties did not differ significantly from that of grass-only manure.

中文翻译：

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用豆科植物叶补充草基牛饲料及其对粪便质量和作为卢旺达 Anthropic Ferralsol 土壤改良剂的价值的影响

石灰、动物粪便和无机肥料的组合使用可有效补充退化酸性土壤的肥力。然而，许多小农无法获得足够数量的这些投入物来提高肥力并降低 Ferralsols 的铝毒性。有机肥料是可用的，但通常养分含量低，这限制了它们向土壤提供养分的能力。在卢旺达南部省的 Anthropic Ferralsol 四个季节的双因素田间试验中，我们评估了 (i) 牛粪对土壤特性的影响，与施用 NPK 肥料相比，小农可负担得起，并且没有石灰也以降低的速度，(ii) 在基础牛日粮中添加草类植物叶对粪便质量的影响及其对土壤特性的影响。只喂草的牛粪黄花菜（仅草肥）和喂牛C.gayana辅以金合欢叶（草+豆类肥料）以 5 吨干物质公顷施用-1（推荐比率的 25%）在每个生长季节开始时。NPK 以分次剂量施用，总供给量为 70 kg N ha-1. 石灰每年以 2.0 吨 CaO ha 的速度施用-1，这是中和现场总酸度所需速率的 25%。所有改良剂仅适用于玉米植物（种植站）周围的土壤，估计占地块面积的 25%。玉米秸秆在收获后留在地块上，并且在所有生长季节都保留了种植站。所有处理都改变了种植站的土壤性质。石灰通常会增加 pH 值，但石灰加粪肥处理与非石灰粪肥处理之间没有显着差异。粪肥和 NPK 处理的土壤有机碳浓度和阳离子交换能力高于未施肥处理。与 NPK 和不施肥处理相比，粪肥处理增加了土壤持水能力。总N、Ca无显着差异2+, 镁2+和 K+在 NPK 和粪肥处理之间。因此，微量动物粪便可以替代矿物肥料和石灰，用于补充小农耕作中的土壤肥力。草+豆类肥料的总氮、钙、镁、钾和钠含量高于纯草肥，但其对土壤性质的影响与纯草肥无显着差异。