Influence of agro-technical measures on chlorophyll activity of soybean plants

Abstract

Goal. To study the laws of functioning of the photosynthetic apparatus of soybean plants under different elements of culture technology. Methods. The experimental field method was used for growing soybean plants of the Siverka variety using advanced technologies, the laboratory-analytical method was used to determine the characteristics of the photosynthetic apparatus of soybean plants, and the statistical method was used to calculate statistical deviations from the mean value. Results. The higher activity of chlorophyll and enzymes of the Calvin cycle in the bean filling phase was observed in soybean plants in the variant with the application of mineral fertilizers in doses of N100P60K100 and N40P40K60 on the background of plowing of exogenous organic matter. Increasing the dose of mineral fertilizers increased the activity of chlorophyll by 56.0%, the activity of enzymes of the Calvin cycle — by 53.1%. With the plowing of by-products on the background of mineral fertilizers, the activity of chlorophyll increased by 33.3%. In the phase of full maturity, the maximum activity of chlorophyll and enzymes of the Calvin cycle was characterized by plants in variants with the application of mineral fertilizers at a dose of N40P40K60 and control (without fertilizers) without plowing by-products of the predecessor in crop rotation. The variant with the maximum dose of fertilizers and high activity of chlorophyll and enzymes of the Calvin cycle during the growing season in the phase of full maturity had the lowest indices among the studied variants. Increasing the dose of fertilizers led to a decrease in the activity of chlorophyll by 48.7%, the activity of Calvin cycle enzymes — by 36.2%. Conclusions. The use of the method of induction of chlorophyll fluorescence allows to objectively assess the physiological state of soybean plants during the growing season and to take into account the significance of the influence of exogenous and endogenous factors.