Yield, soil Nitrogen content and weed control in six years of conservation agriculture on-farm field trials in Southwest Germany

Abstract

Conservation Agriculture (CA) is a farming system that aims to protect soil resources by promoting minimum soil disturbance in combination with the maintenance of a permanent soil cover, and diversification of crop rotation. The aim of this study was to investigate the effects of no-till and shallow conservation tillage using a chisel plough and rotor tiller on loamy soils with high clay contents in combination with cover crop mixtures in rotations with at least three different crops. Crop yield, soil Nitrogen content and weed coverage were the main parameters measured. Experiments were performed in an on-farm approach in southwest Germany on 18 farms and two research stations over a period of 6 years. Yields of cereals, oilseed rape, maize, soybean and peas were slightly lower under no-tillage with 5.8–7.3 Mg grain yield equivalents ha−1 than under conservation tillage with 6.3–7.8 Mg grain yield equivalents ha−1. Cover cropping did not affect crop yields. Tillage and cover cropping had no influence on weed control in the subsequent main crop. Soil nitrate contents before winter in November were on average 11 kg N ha −1 lower in the cover crop treatments compared to the plots without cover crops. This study shows that CA with minimum tillage had slight advantages compared to the no-till system under Southwest Germany farming conditions.