Differentiated application of mineral fertilizers in cultivation of Sudanese grass

Abstract

Research on the use of mineral fertilizers considering the intrasoil variability of agrochemical indicators in the sowings of Sudanese grass of Kinelskaya 100 variety was carried out in 2011 and 2017 in two fields of crop rotation deployed in time (pure fallow - winter wheat – spring wheat – spring wheat – Sudanese grass – spring barley) on leached heavy loamy chernozem (humus in the arable layer – 5.2-7.1 %, nitrate and ammonium nitrogen 6.5-16.9 mg/kg of soil, mobile forms of phosphorus – 83-201 mg/kg of soil and exchangeable potassium – 91-198 mg/kg of soil) in the forest-steppe regions of the Euro-North-East of the Russian Federation (The Republic of Mordovia). The scheme of the experiment included 3 variants with fertilizers (planned yield of green mass of Sudanese grass 20.0 t/ha): control (without fertilizers); average dose of fertilizers (N89P33K30 – in 2011, N92P35K28 – in 2017); differentiated doses (N73-99P21-31K23-32 in 2011 and N70-103P24-40K20-21 in 2017). The experiment was based on the principle of a split plot, where plots of the 1st order were reserved for variants with fertilizers, and plots of the 2nd order (5 plots in each repetition) were used to determine the variability of intrasoil fertility and fertilizer application. On average, among two crop rotation fields, the highest yield of Sudan grass (25.1 t/ha) was obtained in the variant with differentiated use of fertilizers, that was significantly higher than the control (49 %) and 10 % higher than in the variant with average doses. The application of fertilizers considering the heterogeneity of soil fertility ensured the smallest range of variation of the yield (4.4 t/ha) among the plots of the testing ground with an insignificant level of variation coefficient (V = 6 %). The use of fertilizers had a positive effect on the collection of dry matter, feed units and digestible protein per 1 ha. According to these indicators, a significant advantage was observed for the variant with differentiated doses, which also provided the highest level of production profitability (122.3 %).