Alleyway Groundcover Management Impacts on Soil, Pests and Yield Components in Blackcurrants (Ribes nigrum L.)

Abstract

ABSTRACT Vegetation-free soil was compared with natural weed and white clover (Trifolium repens) alleyways in established blackcurrants from 1992 to 1995. The number of earthworms, the development of the cover crops and the occurrence of diseases and pests were assessed. Soil moisture, nutrient content in leaves, fruit set, yield and juice quality were determined. The cover crops did not influence the number of earthworms. The total number of heaps of casting increased from 2.0 m−2 in 1993 to 16.4 m−2 in 1995 as an average of all treatments. The cover crops did not cause a reduction of American gooseberry mildew (Sphaerotheca mors-uvae), white pine blister rust (Cronartium ribicola) or leaf spot (Gloeosporidiella ribis). The top soil moisture percent was significantly higher during 1995 for blackcurrant cv. Ben Lomond (20.8%) than for cv. Ben More (18.7%) as an average of all treatments. ‘Ben Lomond’ showed no differences in soil moisture between treatments, while the vegetation-free ‘Ben More’ had a slightly higher soil water content than the cover crop treated. Leaf contents of total nitrogen, potassium and magnesium were within the optimal levels and were not affected by the treatments. In three out of four years the yield was identically for the different soil treatments, but in 1995 the fruit set and the yield in the cover cropped ‘Ben Lomond’ was reduced compared to the vegetation-free bushes.