The influence of mineral fertilisers, farmyard manure, liming and sowing rate on winter wheat grain yields

Abstract

The influence of mineral fertilisers, liming, farmyard manure and sowing rate on the winter wheat grain yields was studied in a long-term field experiment at 4 sites under different soil and climatic conditions in the Czech Republic. A total of 135 partial fraction-factorial experiments were performed between 1980 and 2013 and evaluated using a statistical model with linear and quadratic terms for each factor. Yield trends demonstrated remarkable influence of fertilisation at two sites of lower starting productivity. Here, grain yields increased by 50% and 25% since the trial commencement, while the rate of yield increase was low at more productive sites. Yields were the most frequently influenced by nitrogen (N) fertilisation, uniformly at all sites. N response curves were strongly curvilinear, but these differed between sites and were affected by preceding crops. The relative frequency of statistically significant influences decreased in the following order: N (significant at α < 0.05 in 89% of all partial trials) > sowing rate (29%) > phosphorus (22%) > farmyard manure (15%) > potassium (12%) > liming (8%). This order and the frequencies of these influences are discussed with regard to relevant site and soil conditions.