Soybean uptake of essential nutrients from soil and fertilizers

The effect of prolonged use of different doses and ratios of mineral fertilizers in 4-field crop rotation on the content of essential nutrients in soybean plants investigated. The work was carried out in a stationary field experiment on chernozem podzolized heavy- loam in the Right-bank Forest Steppe of Ukraine. The article presents the average yield data of soybean and the composition of plant products according to the determinations during 2016-2018, at the time of the second crop rotation. The experiment scheme includes 11 variants of combinations and separate application of mineral fertilizers and, including, the control variant without fertilizer. In the experiment, where the average dose of crop rotation nutrition per hectare is N 110 P 60 K 80 , full (100 %) compensation of essential crop nutrients removal by fertilizers planned. Comparison of the mass of nutrients introduced into the soil with mineral fertilizers with the content of the elements in seeds and straw of soybean determined the close direct correlation according to the following indicators: nitrogen (R 2 =0,82–0,92); phosphorus (R 2 =0,69– 0,80); potassium (R 2 =0,63–0,68). Application of N 110 P 60 K 80 on 1 ha of crop rotation area, compared to areas without fertilizers, increases nitrogen absorbing with the soybean yield by 102%, phosphorus by 86 % and potassium by 100%. It shown that soybean absorbs 52.0–59.4 kg of nitrogen, 20.6–26.9 kg of Р 2 О 5 , and 23.4–26.4 kg of К 2 О by forming 1 ton of seeds and an appropriate amount of straw, depending on the doses and fertilizer ratios in the rotation. With soybean straw, 6–8% of nitrogen return to the soil, 47–54% of phosphorus and 51–52% of potassium from the entire mass of the elements, removed by the harvest (economic removal), depending on the fertilizer system.