Nutrient response and nutrient retention efficiency in temperate agroforestry systems

Agroforestry systems are innovative agricultural systems, which take advantage of beneficial ecological functions of their components, aiming to attain high productivity with possibly less negative environmental effects, e.g. nutrient and carbon losses. However, no comparison of nutrient response and retention efficiencies has yet been conducted between conventional and agroforestry systems. Our study aimed 1) to quantify nutrient response (ratio of biomass production to soil available nutrients) and nutrient retention efficiency (1-leaching losses/soil available nutrient) in conventional and agroforestry systems, and 2) to assess if competition and/or facilitation exists between tree strip and grass/crop in agroforestry systems. We hypothesized that conventional systems will have lower nutrient response and retention efficiencies than agroforestry systems. Our study investigated six paired sites of grassland/cropland and agroforestry with alley cropping of fast growing tree species and crop/grass, located in central and eastern Germany. Measurements in agroforestry were taken within tree strips and at various distances to the tree strips within the crop/grass strips. Results from the 2016/2017 growing season will be presented. This study will provide the presently needed information on whether agroforestry can reduce the negative environmental impacts through gaseous/leaching losses while optimizing production and therefore might be a sustainable alternative to conventional agriculture