Influences of soil tillage, irrigation and crop rotation on maize biomass yield in a 9-year field study in Muncheberg, Germany

To analyze the effects of tillage (no-tillage, plow tillage), irrigation (rainfed, irrigated), and crop rotation (continuous maize, 4-year crop rotation) and their development, we conducted a field experiment over 9 years under sandy soil conditions in northeastern Germany. The generalized linear model showed that tillage, irrigation and crop rotation jointly explained approximately 35% of the total variance. Irrigation and crop rotation significantly positively influenced maize biomass yield started immediately in the first years in 2008 and 2011 respectively, while tillage started to significantly positively affect yield starting from the fourth year. In general, irrigation had the most relative importance as a management factor compared to the importance of tillage and crop rotation. Crop rotation with legumes increased soil nitrogen and carbon content and led to a higher yield than continuous maize 11.1 dt ha(-1) y(-1) in average. Furthermore, the significant effect of crop rotation on the yield of the following crop (maize) continued after 2 cycles of a 4-year crop rotation. A significant influence of the 2-way interactions between rotation, tillage and irrigation was only found in extremely dry years. It can be concluded that (i) the negative influence of no-tillage becomes noticeable after 3 years, leading to significantly lower yield compared to plow tillage; (ii) under the sandy soil and dry conditions, irrigation significantly increases yields and is the most important factor compared to tillage and crop rotation; and (iii) crop rotation significantly increases and maintains maize yield under both plowed and irrigated conditions.