Removal and balance of nutritional elements in the agrocenosis of sorghum for grain depending on fertilizer system

Abstract

Goal. To study the peculiarities of the use and balance of nutrients of sorghum for grain plants using different fertilizer systems. Methods. Field short-term — to study the effect of doses and timing of mineral fertilizers on the nutritional regime, growth dynamics, and development of sorghum for grain; laboratory — to establish quantitative and qualitative characteristics of the soil; mathematical — to calculate the yield and removal of soil elements. Results. The data of researches on the use of nitrogen, phosphorus, and potassium by plants, their circulation, and balance in the agrocenosis of sorghum for grain at different doses and methods of use of nitrogen fertilizers are given. It was found that plants of sorghum for grain when grown in conditions of unstable moisture on typical weakly saline medium loam chornozem reacted positively to the introduction of high doses of nitrogen (N120–150) in pre-sowing cultivation. Nitrogen and phosphorus fertilizers were concentrated mainly in plant grains, potassium — in stems. The removal of nutrients from the soil and their balance depended on the doses of mineral fertilizers and the method of using the biological crop. Conclusions. The plants of sorghum for grain removed from the soil with marketable products mainly contain nitrogen, and with the side products — potassium. An ecologically stable fertilizer system was determined for sorghum for grain with grain yield over 8 t/ha. It was an application in pre-sowing cultivation of N150 on the background of P90K90 for plowing without removal from the field of by-products: nitrogen balance intensity — 108%, phosphorus — 300, potassium — 250% with accumulation in soil nutrients — 11, 60, and 54 kg/ha respectively. By removing from the field only the commodity harvest, a balanced balance of nutrients in typical weakly saline chornozem can be achieved with reduced doses of mineral fertilizers: P30K40 for plowing + N140 in pre-sowing cultivation. Such a fertilizer system is cost-effective and environmentally stable for the cultivation of sorghum for grain.