DIAGNOSTIC INDICATORS OF SOIL FERTILITY IN CROP ROTATION WITH LUPINE UNDER DIFFERENT METHODS OF PRIMARY SOIL CULTIVATION

The results of studies on the influence of primary tillage methods on the biological activity of gray forest soil in crop rotation with lupine and, as a consequence, on the change in humus content are presented. The purpose of the studies is to study the state of soil fertility of gray forest soil with different primary tillage methods in crop rotation with lupine. The studies were carried out on the gray forest soil of the southwest of the Non-Chernozem zone of the Bryansk region of the stationary experiment of the All-Russian Research Institute of Lupine in 2019-2022. The most intensive microbiological activity of the soil was observed in all variants of the experiment in the 0-10 cm layer. The microbiological activity is affected by the method of soil cultivation. Thus, in the 0-10 cm layer with no-till cultivation this indicator is maximum (39%), 24% higher than with plowing, and 16.9% higher than with chisel plowing once every 4 years in crop rotation under lupine. The most promising system of primary soil cultivation in terms of humus conservation and reproduction is the non-moldboard system of primary soil cultivation. With this method, a smaller decrease in humus of gray forest soil was revealed over 8 years (by 0.25 and 0.41%); with moldboard cultivation, the decrease was 0.50 and 0.80%. The degree of humification of organic matter in grain crop rotation has significantly decreased over the years of research to 22.1% with no-till cultivation and to 18.4% with moldboard plowing. Humus of gray forest soil before the experiment was of the humate type, under all soil cultivation systems. After 8 years in grain crop rotation with lupine, without any plowing of lupine for green manure, the humus type changed to humate-fulvate, during moldboard tillage of soil with a ratio of Сhum.acids:Сfulv.acids within 1-05. And for the fulvate-humate type with no-till soil cultivation, with a ratio of Сhum.acids:Сfulv.acids within 1-2.