Fertilisation, rainfall and crop yield

Abstract

The effect of rainfall quantity and distribution and of N, P, K, Ca and Mg fertilisation on the yields of rye, potato, winter wheat and triticale were evaluated in the 42 years of a long-term mineral fertilisation experiment [soil (acidic, sandy, brown forest) × fertilisation (N, P, K, Ca, Mg) × rainfall (quantity, distribution) × crop (rye, potato, winter wheat, triticale)] set up in 1962 under fragile agro-ecological conditions in the Nyírlugos-Nyírség region of Eastern Hungary. The soil had the following agrochemical characteristics: pH (H2O) 5.9, pH (KCl) 4.7, hydrolytic acidity 8.4, hy1 0.3, humus 0.7%, total N 34 mg kg-1, ammonium lactate (AL)-soluble P2O5 43 mg kg-1, AL-K2O 60 mg kg-1 in the ploughed layer. From 1962 to 1980 the experiment consisted of 2×16×4×4=512 plots and from 1980 of 32×4=128 plots in split-split-plot and factorial random block designs. The gross plot size was 10×5=50 m2. The average fertiliser rates in kg ha-1 year-1 were nitrogen 45, phosphorus 24 (P2O5), potassium 40 (K2O), magnesium 7.5 (MgO) until 1980 and nitrogen 75, phosphorus 90 (P2O5), potassium 90 (K2O), magnesium 140 (MgCO3) after 1980. The main results and conclusions were as follows: The rainfall quantities averaged over many years and in the experimental years, and during the growing season, averaged over many years and in the experimental years, were 567, 497, 509, 452 mm for rye and 586, 509, 518 and 467 mm for winter wheat. Rainfall deviations from the many years' average -3% and -13% in the experimental years and during the growing season for potato and 2% and -3% for triticale. During the vegetation period the relationships between rainfall quantity, NPKCaMg nutrition and yield could be characterised primarily by quadratic correlations. Maximum yields of 4.0 t ha-1 for rye, 21.0 t ha-1 for potato, 3.4 t ha-1 for winter wheat and 5.0-6.0 t ha-1 for triticale were recorded when the natural rainfall amounted to 430-500, 280-330, 449-495 and 550-600 mm, respectively. At values above and below these figures there was a considerable reduction in the yield. The results showed that the crop yields were strongly influenced (quadratic correlation) by interactions between N, P, K, Ca and Mg fertilisation and rainfall quantity and distribution.