Balance of calcium, magnesium and phosphorus in short-rotary cultivations of the forest-steppe

Abstract

The purpose of research. Give a comparative comprehensive assessment of the balance of phosphorus, Ca and Mg and establish a hierarchy of subordination of balances with the productivity of short-rotation crop rotations for long-term use of organo-mineral fertilizer system using by-products of crops as organic fertilizers for Central Forest-Steppe of Ukraine. Methods. The generally accepted methods of researches were applied: field, laboratory, mathematical methods, comparative-settlement. Research results. Regardless of the structure of short-rotation crop rotation, the balance of Ca and Mg was deficient, and the balance of Ca exceeded the balance of Mg by 4.88 times. The balance of Ca was 1.74 times more stable by the coefficient of variation. Between the components of the phosphorus balance and the balance of Ca revealed 62.5% of correlations of medium and strong level, between the turnover of Mg–9.14%, and between the components of the balance of Ca and Mg revealed 34.7% of paired correlation coefficients, indicating subordination balances in the sequence: Mg next Ca then R. Between the balance of Mg and Ca and performance, the relationship was at a low functional level. The ratio of Ca to Mg in the components of the balances did not exceed the optimal values: in the main products the ratio was 1.3 to 1, and the normalized interval varied from 0.9 to 1 to 1.6 to 1. The widest ratio of Ca to Mg was in by-products 2.3–3.7 to 1 with a normalized interval of 2.7–5.0 to 1. Conclusions. When expanding the ratio of the balance of Ca to Mg > 3 to 1 and when reaching the balance of Ca > 800 kg / ha, the circulation of phosphorus is blocked, which leads to a decrease in crop rotation productivity at the yield of k.o. up to 4.0-4.5 t / ha, and with the narrowing of the ratio of Ca to Mg to 2.5 to 1 and 1.5–2.0 to 1 there is an increase in productivity to 5-6 t / ha and 6.0–7.0 t/ha from 1 hectare. According to the established criterion of the ratio of Ca to Mg in the circulation of macronutrients, crop rotations can be classified according to increased soil protection capacity (Ca to Mg > 3) and crop rotations with high productivity (Ca to Mg <2). Crop rotations with a ratio of Ca to Mg 2.0-3.0 to 1 are intermediate in nature and combine soil protection properties with high productivity.