THE SOWING TERM EFFECT ON SEED QUALITY, ECONOMIC AND ENERGETIC EFFICIENCY OF SOYBEAN CULTIVATION

Abstract

The nutritional value of soybean seeds is in high protein (up to 35%) and fat (up to 25%) percentage. In the Russian Federation, there is a positive trend in increasing the soybean acreage (e. g. from 1.537 million hectares in 2013 to 2.919 million hectares in 2018). The field trials were carried out in the laboratory of cultivation technology of row crops of the FSBSI “Agricultural Research Center “Donskoy” (Zernograd, southern soil-climatic region of the Rostov region) in 2016–2017. The experiments were conducted with the varieties of local breeding “Don 21” and “Diva”, included in the State Register of Breeding Achievements of the Russian Federation in 6 regions, differing in the length of vegetation period. The soil of the experimental plot is favorable for soybean cultivation, the humus content in the topsoil is 3.36%; pH is 7.0; P2O5 is 24.4; K2O is 360 mg/kg of soil. Depending on the sowing period, the soybean yields varied from 0.85 to 1.25 t/ha for the variety “Don 21” and from 0.77 to 1.38 t/ha for the variety “Diva”. The protein content in soybean seeds was the highest in the fourth term of sowing (41.9 and 39.8%), and the fat content in the first term was 19.0 and 20.2% (the varieties “Don 21” and “Diva” respectively). The analysis of economic and energy efficiency identified the most effective variants of the trial. The variety “Don 21” had the second sowing period, the variety “Diva” had the third one, with the highest values of profitability (129.8 and 147.7%) and the energy efficiency ratio (2.03 and 2.18).