Effectiveness of sowing alfalfa in intensive systems of crop rotation

Abstract

The effectiveness of sowing alfalfa with and without cotton stems harvesting under the cover of winter wheat to improve soil fertility was determined. Investigations were carried out under conditions of light meadow soils in Fergana Region of the Republic of Uzbekistan. The objective of the research was to determine the productive capacity of irrigated lands in the system of cotton/grain crop rotation. Spring alfalfa sowing contributed to increasing soil organic matter up to 13.6-14.0 tonnes per ha. When sown alfalfa in autumn, 11.2 - 11.4 tonnes per ha of organic matter was accumulated in the arable and subsurface layers because of reducing plant density that was 10.3% lower than in spring. Increased soil organic matter contributed to reducing bulk density of soil by 0.02-0.04 g/cm3. It has been found that the cultivation of alfalfa increases the amount of total nitrogen in soil by 9.3-17.8% as well as of agronomically valuable soil aggregates (> 0.25 mm) in the arable layer 1.1-1.2 times in comparison with the control variant.