Advantages of grass-grain crop rotations due to prolonged use of clover-alfalfa-timothy mixture

Abstract

It is known that significant saving of nitrogen fertilizers are due to perennial legume-cereal grasses use in crop rotations. From 2013 to 2018in the Mari El Republic six-field grass-grain fodder crop rotations were compared on sod-podzolic soils with a very high level of phosphorus and potassium. In the third rotation their productivity and bioenergetic efficiency, changes in several important soil fertility indicators, and crud protein content in the produced fodder were evaluated. The main difference between the crop rotations was based on the duration of the clover-alfalfa-timothy grass mixture (CAG) use: from one year to three years. In given experiment there was also studied the effect of mineral nitrogen (variants N0, N60) against Р60К60 background on the yield of crop rotations. During six years, there was no significant soil acidification in the variants. Each additional year of clover-alfalfa-timothy grass mixture use raised the energy efficiency ratio of crop rotations by 24-47 % (from 1.13-1.24 by one-year use to 2.08-2.25 by three years of use). Three-year CAG use as compared with one- and two-years has given to the crop rotation significant advantages in energy efficiency (up to two times) and productivity (approximately 40-80 %) of cultivated crops. After refusing to apply nitrogen fertilizations in such crop rotation, average crop productivity, soil humus and nitrogen content in the soil were better preserved. The average crude protein content in dry matter of the obtained fodder increased from 12.7 % to 14.6 % when prolonging theca use up to two years. The average energy value of the yield per rotation was recorded low (8.4-8.7 MJ/kg) and did not depend on the studied factors.