Vorfruchtwirkungen verschiedener Blattfrüchte auf Winterweizen und Einfluß von Anbaumaßnahmen

Abstract

Effects of preceding “break crops” on winter wheat and influence of cultural practices Between 1979—83 there was tested the effect of 5 “break crops” (biennial alfalfa, clover‐grass, faba bean, winter‐rape, silomaize) on succeeding winter wheat and the interaction with changed cultural practices such as N‐fertilization and conventional or reduced primary tillage (plough ↔ rotary tiller). After the break crops wheat yield decreased within a range of 4 dt/ha as follows: alfalfa → beans → rape/ clover‐grass/maize. Raising N‐fertilization hardly allowed to improve the value of the break crops; most likely that of maize and with rotavating. Adaption of N‐dressings promised greater influence. The manner of primary tillage exerted stronger influence on the yield than the level of N‐fertilization. Concerning long‐term yield the rotary tiller equaled the plough after 4 break crops; after faba bean it was superior. Increasing N‐fertilization tendentially favoured the rotary tiller after bean, rape and maize. Using the rotary tiller, at beginning of growth there may be calculated on 15 % higher NO3‐values and/or higher N‐mineralization or N‐transformation. Eyespot disease could not be prevented sufficiently and purposefully by an other break crop, N‐fertilization or primary tillage. Recurrent rotavating suppressed weed less than ploughing.

Nitrogen Rate Increase Not Required for No-Till Wheat in Cool and Humid Conditions

“…In general, the soil N min content at the beginning of the vegetation period varied in similar ranges of about 25 to 65 kg N ha −1 for the different tillage systems (Figures 1 and 2). The soil N min contents were usually higher after oilseed rape than after maize, as was also found by other authors [50,51]. Similarly, less soil nitrate was released after different cereals than after oilseed rape and higher soil N min contents were found during spring when wheat followed oilseed rape than when it followed cereals [52,53].…”