The application of vegetable, fruit and garden waste (VFG) compost in addition to cattle slurry in a silage maize monoculture: Effects on soil fauna and yield

In Flanders, vegetable, fruit and garden (VFG) wastes are collected selectively and composted. We studied the effects of the combined application of three different doses of VFG compost and cattle slurry during 7 years on maize dry matter yields and three soil faunal groups: nematodes, micro-arthropods (springtails and mites) and earthworms. Combined application of VFG compost and slurry resulted in the highest yields. Initially, there was a clear yield depression on plots amended with compost in contrast to an upward trend in the last application years, proving a significant residual N effect from cumulative compost applications. The plant parasitic nematodes Pratylenchus sp. and the Tylenchidae were less abundant on plots receiving organic amendments, while the population of the bacteriophagous Rhabditidae was higher on these plots. Adding organic amendments resulted in increased numbers of micro-arthropods, springtails as well as mites. Earthworms were significantly more abundant when organic amendments were applied. The VFG compost had a larger overall positive effect on the three soil faunal groups than cattle slurry.