The root growth of Salix viminalis and Eucalyptus nitens in response to dairy farm pond effluent irrigation

The spatial root distribution after two years of three energy crops was investigated, with the influence of two rates of dairy pond effluent application, applied every fortnight. The roots of Salix viminalis PN 386 and NZ 1295 and Eucalyptus nitens were studied using soil cores. It was found that spatial distribution was influenced by effluent rate, with greater quantities of both fine and coarse roots in the top soil horizons with the higher effluent rate of 300 m3 ha−1 compared to 150 m3 ha−1. The study has implications on the harvesting of such crops using heavy machinery which could cause root damage and lessen vigour in the second rotation.