Spring soft wheat yields on developed compound fallow lands of the steppe zone of West Siberia

Abstract

The study deals with yield dynamics of spring soft wheat variety Sunset on fallow lands of the steppe zone of West Siberia; the fallow lands were developed with BDM 6×4 disc harrow without preceding plowing. The field experiments were carried out from 2021 through 2024 in the Russko-Polyanskiy District of the Omsk Region on ordinary chernozems with varying degrees of alkalinity. The research goal was to evaluate the effectiveness of using fallow lands for spring wheat sowing and to develop guidelines for maintaining soil fertility. The research findings showed that the highest yield (2.12 t ha) was achieved on the first year after the fallow land was introduced into production. However, by the third year, the yield decrease by 24% (to 1.6 t ha) which was associated with the soil layer depletion (the humus content decreased to 5.3%) and increased weed infestation (predominance of millet-like weeds). Comparative evaluation of the soil-tilling and seeding units revealed the advantage of SevMaster-10 unit over Condor unit in terms of seed placement depth (5-6 cm) and field germination (+15-20%). Soil sample tests on the third year of the land use showed the deficiency of available nutrients: nitrate nitrogen - 5.3 mg kg, mobile phosphorus - 37 mg kg, and exchange potassium - 298 mg kg. The deterioration of soil physical properties was also revealed: water permeability decreased, and soil hardness increased to 4.3 g cm². The main reasons for yield decrease were the following ones: decreased nutrient availability, increased weed infestation and deterioration of the agrophysical soil properties. For the efficient use of fallow lands, the following is advised: implementation of scientifically based crop rotations; application of mineral fertilizers; use of ameliorants on solonetzic soils; regular monitoring of soil fertility.