Mineral NPK and manure fertilisation affecting the yield stability of winter wheat: Results from a long-term field experiment

Abstract

Abstract It is well known that a balanced nutrient supply ensures high crop yields and stable cropping systems. In comparison, little is known about the influence of different fertilisation regimes on the yield stability of crops. Therefore, the objective of this study was to identify the impact of mineral and organic fertilisation supplied in different combinations (P + K/N + P/N + K/N + P + K) and levels (50%/100%/100% + manure) on the stability of the winter wheat grain yield. A long-term fertilisation field experiment at Giessen University (Germany, temperate climate, silty clay), established in 1956 with a multifactorial set up, was used. For an accurate stability analysis that matches the experimental design, we subjected the data to a mixed model analysis based on the restricted maximum likelihood (REML) method calculating Shukla‘s stability variance and Finlay–Wilkinson regression and performing Eskridge's risk analysis. It was found that without any nutrient supply, the wheat yields exhibited high annual variability and only modest stability. A similar pattern was identified for the fertiliser combination of the minerals P + K. The combinations containing mineral N showed a significant improvement in yield stability in which N + P and N + K are almost identical. In all fertilisation variants, the additional supply of manure stabilised the wheat yields. The mineral supply of N + P + K with additional manure provided the best yield stability and lowest agronomic risk for yield failure.