The change in grain yield by rotation of crop rotations of the chernozem steppe of the Lower Volga region

Abstract

The influence of rotation length and fullness of grain – fallow crop rotations with a different set of biological groups (biogroupps) - winter, early spring and late spring crops on the yield of grain crops and grain yield from 1 hectare (ha) of arable land in the chernozem steppe of the Saratov Right Bank is analyzed, based on calculations for 4-field - 8 rotations, starting from 1989 and ending in 2020 (2-field - 16 rotations, 3-field - 10). It was revealed that the highest grain yield of 1.63 tons (t) from 1 ha of arable land, both on average for 32 years (1989-2020), and (1.82 t / ha) in the first-fourth (1989-2004) and (1.44 t/ha) of the fifth-eighth rotations (2005-2020), is observed in the 4-field grain – fallow crop rotation with a set of biogroupps-winter, spring early and late. The absence of a field of spring late crop (millet) in the 2 - and 3-field crop rotations reduces the grain yield by 0.11 and 0.30 t/ha, respectively, in comparison with the 4-field, both on average for all years, and by 0.22 and 0.28 t/ha in the first-fourth and by 0.20 and 0.32 t/ha in the fifth-eighth rotations. During the transition from the first-fourth rotation to the fifth-eighth, a significant decrease in the yield of field crops was established: winter wheat in the 3-field crop rotation by 0.87 t/ha or 26.6 %, 2-field by 0.72 t/ha or 22.4% and 4-field by 0.70 t/ha or 21.8 %; millet by 0.43 t/ha or 16.3 %, spring hard by 0.40 t/ha or 29.6 %, soft by 0.35 t/ha or 24.6 %. In all three spring crops, the yield reduction is 2.0 times lower than that of winter wheat. In general, according to crop rotations, the yield of winter wheat, both for the entire period of research, and in the first-fourth, fifth-eighth rotation, fluctuated within limited of the error of the experiment.