Effect of a new organic management system with plant-based fertilisers on phosphorus in soil and crop, and yields in a 5-year vegetable rotation

Summary

Achieving adequate phosphorus (P) levels without manure from conventional farms is challenging for organic vegetable farmers. The potential of plant-based fertilisers (PBFs) to replace animal-based fertilisers (ABFs) was examined based on a 5 year, multifactorial crop rotation experiment. Two crop rotations on a sandy loam soil were compared: a standard organic rotation (ST) with clover undersown in spring barley, cabbage, celeriac, corn, and onion. This rotation received inversion tillage, ABFs, and bare soil between cash crops. In contrast, a new organic management system aiming at sustainable intensification (SI) had pure clover without barley, and onion was intercropped in relay with lettuce. This rotation received reduced tillage, PBFs, and cover crops. Soil and crop P were analysed, yields were quantified, and a sequential soil P fractionation was conducted to analyse P dynamics.