Efficient use of nutrients is a key requisite for a sustainable intensification of agriculture in order to meet the increasing global crop demand while minimizing deleterious environmental impacts. Agroforestry systems exhibit tree–crop interactions, which potentially contribute to nutrient-efficient agro-ecosystems. Our goal was to determine whether the conversion from cropland monocultures to alley-cropping agroforestry increases nutrient response efficiency (NRE), the ability of plants to convert available nutrients into biomass. We found that crop yield, plant-available nutrients and NRE were comparable between agroforestry and monocultures, but the trees in agroforestry had high NRE, contributing to nutrient retention of the agroforestry systems as a whole. The unimodal relationship of the crops’ NRE with plant-available nutrients suggests that NRE values were beyond optimum in both agroforestry and monoculture indicating nutrient saturation. This indicates that fertilizer inputs can be reduced (or optimized) without sacrificing crop yield or profit. Based on the NRE curves, we assessed that a reduction of plant-available N by 50% would lead to a decrease in crop yield by 17% and a concomitant increase in N response efficiency by 67%, whereas a similar reduction of plant-available P would lead to a decrease in crop yield by 8% with an increase in P response efficiency by 83%. An optimized fertilization to achieve such lower levels of plant-available nutrients will have beneficial effects on nutrient retention and redistribution. Optimizing fertilizer input will make alley-cropping agroforestry a productive and profitable agro-ecosystem that contributes to an ecologically sustainable agriculture.

有效利用养分是可持续集约化农业的关键条件，以便满足不断增长的全球农作物需求，同时最大程度地减少对环境的不利影响。农林业系统表现出树木与作物的相互作用，这可能有助于养分高效的农业生态系统。我们的目标是确定从农田单一种植向小巷农林业的转化是否提高了养分响应效率（NRE），即植物将可用养分转化为生物质的能力。我们发现农林业和单作栽培之间的作物产量，植物可用养分和NRE相当，但是农林业中的树木具有很高的NRE，有助于整个农林业系统保持养分。作物NRE与植物可用养分的单峰关系表明，在农林业和单一栽培中，NRE值均超出最佳值，表明养分饱和。这表明可以减少（或优化）肥料投入而不牺牲作物的产量或利润。根据NRE曲线，我们评估了将植物有效氮减少50％会导致作物产量降低17％，同时氮响应效率提高67％，而植物有效氮的减少量与此相似磷将导致农作物产量降低8％，磷响应效率提高83％。达到如此低水平的植物可用养分的优化施肥将对养分保留和再分配产生有益影响。