YEILDNESS OF GREEN MASS OF FORAGE CROPS IN GRAIN PLANTS CROP ROTATIONS

Abstract

 This study focuses on evaluating the green mass yield of forage crops in grain-grass crop rotations with varying durations of using a clover-alfalfa-timothy grass mixture, considering certain abiotic factors. A stationary experiment conducted from 2013 to 2018 investigated three third-rotation crop rotation schemes: with one-year (A1), two-year (A2), and three-year (A3) utilization of the clover-alfalfa-timothy mixture. Two levels of mineral nutrition (N0 and N60) were also studied against a background application of P60K60. The highest above-ground biomass yield was observed with two cuttings of the perennial grasses, averaging 17.6±0.9 t/ha, which represents a 14.2% increase compared to single-cut management. However, the drought in 2014 reduced the productivity of the second cut by half (2-fold) in the A2 rotation and by 1.4 times in the A3 rotation. The maximum green mass yield was recorded in 2015 within the A3 rotation, reaching 23.1 t/ha, 33.8% higher than in preceding years. Winter rye demonstrated high yield stability, averaging 15.4±1.1 t/ha regardless of the Selyaninov hydrothermal coefficient (HTC) and other studied factors. The application of N60 increased rye productivity to 17.5±1.0 t/ha (a 32.6% increase). Mustard, sown as a catch crop after cutting, showed a dependence on the HTC, with maximum yield (8 t/ha) achieved at an HTC of approximately 1.3. It was established that increasing the proportion of perennial grasses in the crop rotation did not consistently lead to higher green mass yield; the average annual yield in the A2 rotation was 15.1 t/ha, which was 31.3-37.0% lower than in the A1 and A3 rotations (19.8-20.7 t/ha). Humus content showed a positive correlation with yield: a 0.1% increase in humus corresponded to a 1.9% increase in green mass yield. The results indicate that the key factors influencing green mass formation for the studied crops are moisture availability (optimal HTC range 0.8-2.3), the level of mineral nutrition (yield increase from nitrogen application up to 24.0%), and soil humus content.