Productivity of crops in rotation, removal of nutrition compounds and payment for fertilizers when using them and humate

The article presents the experimental study results concerning the effect of various fertilizer and humate doses on productivity of crops in rotation, including annual grasses (vetch-oat mixture, winter rye, potato, barley), the removal of nutrients by crops with the harvest, the agronomic efficiency of the studied fertilizer doses. The soil of the experimental plot is soddy-podzolic, medium loamy, of medium cultivation. The repetition of the experiment is 4-fold, the placement of variants is systematically complicated, the size of the plot is 14m x 10m, the area of the plot is 140 m2, the registration area for 2-factor studies is at least 24 m2. The experiment scheme for the years of research is as follows: a nonfertilizer variant (control) (1), a sowing and planting fertilizer N17P17K12 variant (2), two variants of the studied mineral fertilizer systems, differing in nitrogen dose of N93P41K136 and N126P41K136 (3, 4), an organo-mineral system variant, being an equivalent in fertilizer dose to the third variant of the mineral fertilizer system N58P20K111 + 40 t/ha of rotted manure (5). In the experiment, the two factors have been studied, that is factor A - fertilizers and factor B - Na humate, therefore, each plot has been divided into two halves. The first half has not been treated with humate, and another one has been treated with humate at the rate of 0.5 kg/ha at a flow rate of a working water solution of 250L. The research methods are universally accepted ones. In 2020-2021 the crop rotation productivity after fertilizer application has reached 4.3 - 6.1 tons of fodder units/ha per year in average, which has provided 110 - 122% of the planned level of the calculated fertilizing systems. Humate application has resulted in increasing productivity by 0.3 - 0.5 t fodder units/ha per year. The output of the main products has changed little depending on the studied doses of fertilizers and humate, amounting to an average of 86 - 87% over the years of research. Various doses of fertilizers have increased nitrogen removal by 1.2 - 1.9 times, phosphorus removal - by 1.3 - 1.8 times and potassium removal - by 1.3 - 1.9 times compared to the control. Na humate has increased nitrogen removal by 3-9%, phosphorus removal by 6-7%, and potassium removal by 3-4%. The calculated fertilizer doses have provided payment for 1 kg of primary fertilizer nutrient with an increase of 7.0 - 8.2 kg of fodder units. Humate application has increased payment for 1 kg of primary fertilizer nutrient by 0.4 - 2.2 kg fodder units. The highest value has been achieved under the minimum fertilizer doses.