Organic apple orchard fertilisation: row and inter-row management with legume intercrops (BIOFRUITNET Practice Abstract)

Summary

Soil fertility and orchard biodiversity (including soil biodiversity) increase, and nutrients are better balanced.
Practical recommendation
The efficiency of the intercrops is strongly dependent on the appropriate selection and management of the leguminous species.
• The best results were obtained with perennial legumes, such as white clover (Trifolium repens, better the micro- or nano-ecotypes, Picture 1) in combination with sheep fescue (Festuca ovina - Picture 2), or mixtures of leguminous species (e.g., micro white clover + Medicago lupulina + Lotus corniculatus + T. incar-natum).
• Key factors for good establishment of the intercrop are:
a) correct sowing time
b) minimising soil disturbance until the intercrop is fully established
c) sufficient water availability during germination and establishment
d) use of high seed density (up to 2 g/m2) to avoid initial competition by weeds
• The legumes (including peas) can also be sown on the tree row to produce green manure for early-season incorporation into the soil.
• When enough biomass is produced, the legume(s) must be incorporated into the soil, at the latest in July (depending on the specific site), to match nitrogen mineralisation with the trees’ demands.