Influence of polymeric absorbents and mulching materials on preservation of soil moisture reserves and soybean yield

Various methods of soil moisture reserves preserving: by reducing its physical evaporation and lowering the gravitational flow from the root zone, were estimated on the ordinary chernozem, in the conditions of unstable moistening of the east zone of the Krasnodar region. During a field experiment, the efficacy of introducing intrasoil moisture absorbents and mulching of a soil surface between the soybean rows by a black polyethylene film, nonwoven fabric and chalk was evaluated. Soybean was planted into two dates: early (March 11) and optimal (April 18). Polymeric moisture absorbent (hydrogel) was applied in a dose of 400 kg per ha to a depth 9-10 cm before soybean sowing. After seedling appearance, inter-row surface has been covered with the mulching materials. As a control was used variant without polymeric moisture absorbent and mulching materials application. Humidity of the soil and yield account were determined in accordance with the generally accepted methods. There were obtained the preliminary results. The variant with the covering of soil surface between rows with a polyethylene film and the simultaneous introduction of a polymeric hydrogel into the root layer preserved the greatest amount of productive moisture in the soil layer 0-30 cm during the soybean vegetative period. The yield from the plots that were covered a polyethylene film exceeded the control one at an early sowing date by 18.7%, at the optimal sowing date - by 22.6%. The maximal soybean yield was obtained in cases with complex use of mulching materials and polymeric moisture absorbent. The yield increase constituted 26.8-32.2 %, depending on sowing date. Oil content in seeds practically did not depend on the sowing dates and experiment variant. Oil yield was significantly higher from the plots that were covered with a polyethylene film. Excess of control indicators at early sowing date constituted 20%, at optimal sowing date - 25.6%. Additional introduction of polymeric hydrogel into the soil in a dose of 400 kg per ha allowed to increase oil yield on 26.6 and 38.5%, respectively.