Agroecological effi ciency of organic fertilizers’ placement methods

Abstract

The results of studies on the effect of bare and green-manured fallow (melilot, peas, peas + oats), as well as methods of placing green manure crops and manure (plowed to a depth of 18–20 cm and cultivated at 8–10 cm) on the fertility and productivity of dark chestnut soil are presented. Field experiment took place in the steppe zone of the Republic of Tuva. The weather conditions during the study period were noted as characteristic for the conditions of the steppe zone: 2016 and 2017 were arid, whereas 2018 was wet. Bare fallow was more effective for the accumulation of productive moisture than green-manured one both in autumn and in spring before sowing spring wheat. In autumn, after bare fallow, the moisture content was higher by 14.7%, in spring by 32.8%. The surface placement of green manure crops contributed to a lesser desiccation of the soil. The best supply of nitrate nitrogen before sowing wheat was noted in fallow fi elds with manure and melilot (17.1-15.6 mg/kg). Methods of placing organic fertilizers did not affect the nitrate content in the soil. The yield of spring wheat was affected by preceding crops and methods of placing fertilizers. The highest yield of spring wheat was obtained in the bare-fallowed fertilized fi eld, which was by 0.2–0.5 t/ha higher than with all types of bare or green-manured fallow. Deep (18–20 cm) placement of manure increased the yield of spring wheat by 0.2 t/ha (10.5%). Placement of green-manured crops on the surface made it possible, on average during the experiment, to increase this indicator by 0.1–0.3 t/ ha (7.1–20%).