ASSESSMENT OF THE USE OF PHOTOSYNTHETICALLY ACTIVE RADIATION BY SOYBEAN ON IRRIGATED LANDS IN ROSTOV REGION

Abstract

Purpose: assessment of the use of photosynthetically active radiation (PAR) by soybeans while using the improved cultivation technology on irrigated lands in Rostov region. Materials and methods. The studies were carried out on irrigated lands at Bessergenevskoe Agricultural Enterprise LLC in 2019–2021. The laying of field experiments on soybean crops, recording and observations were carried out according to the methods of VNIIMK and All-Union Scientific Research Institute of soybean. In the experiments, the following soybean varieties were sown: SK Optima, SK Riana, Selecta 201, Selecta 302, SK Veda. The method of A. A. Nichiporovich was used to calculate the use of PAR. Indicators of solar radiation were determined according to the data of the meteorological station in Gigant. Results. As a result of the research, the indicators necessary for calculating the capacity utilization (CU, an analogue of Efficiency) of the PAR under the conditions of Rostov region were specified: the duration of the soybean vegetation and total solar radiation for this period, the core product yield and the by-products biomass, the ratio of soybean seed yield to by-products, energy value of the core product and by-products. It has been found that the level of seed yield of soybean varieties on average for three years of research varies within the range of 3.96–4.66 t/ha, the maximum indicator was obtained for the cultivar SK Riana. Conclusions. The studies allowed determining the total mass of soybean plants, including the core product: the seed yield of the studied soybean varieties is from 3.96 to 4.66 t/ha, and of the by-product is from 4.79 to 5.64 t/ha absolutely dry mass with a ratio of 1:1.21, the energy content of the core and by-products and calculating the utilization capacity of the total radiation Kfar. Calculations showed that the Kfar soybean utilization factors depend on the total solar radiation received and the mass of the substance synthesized by soybean plants and reach 1.43 and 1.48 % for the cultivars SK Optima and SK Veda, respectively (this characterizes the crops of these varieties as ordinary) and 1.61; 1.62 and 1.67 % for cultivars Selecta 201, Selecta 302 and SK Riana, respectively (this characterizes the crops of these varieties as good).

Keywords

• soybean
• photosynthetically active radiation
• photosynthesis
• solar radiation
• yield