Short-Term Effects of Differentiated Tillage on Dry Matter Production and Grain Yield of Autumn and Spring Sown Grain Legumes Grown Monocropped and Intercropped with Cereal Grains in Organic Farming

Abstract

Conservation tillage techniques offer considerably reduced soil erosion and improved soil structure but they are rarely used in organic farming systems due to the potentially increased weed pressure. For the use in the transition period to conservation tillage in organic farming, this study investigated the dry matter production, weed suppression and grain yield of winter and spring faba bean (Vicia faba L.), field pea (Pisum sativum L.) and spring narrow-leafed lupin (Lupinus angustifolius L.), monocropped and intercropped with winter wheat (Triticum aestivum L.; winter crops) and oats (Avena sativa L.; spring crops). The different species were grown in no-tillage, reduced tillage and plough tillage systems at three sites in south-eastern Germany. In the no-tillage system the winter field pea grain yields of up to 3.39 Mg ha–1 were similar to the plough tillage system. For spring faba bean and field pea the yield in the reduced tillage system amounted to 2.92 and 3.29 Mg ha–1, respectively which was similar to the plough tillage system, but exceeded not 2.15 Mg ha–1 in the no-tillage system. Narrow-leafed lupin displayed consistently yields below 0.65 Mg ha–1 in the no-tillage system. Normal leafed winter field pea appeared best suited for the transition period to an organic no-tillage system due to the autumn seeding and its high competitive ability. Spring faba bean and field pea can be grown successfully in the reduced tillage system. Intercropping can increase the total grain yield and weed competition as long as sufficient soil nitrogen resources are plant available.