Humus state of Dark Chestnut soils derived from rice crop rotation

The humus state of Dark Chestnut soil on the territory of the Proletarian irrigation system used in rice crop rotation and derived from it 20 years ago has been studied. As a comparison, a similar soil of a fallow site located in the immediate vicinity from rice field (200 meters) was used. The flooding of the rice soil was accompanied by negative changes in the humus state, including a decrease in humus content and a change in its quality towards fulvic acids increasing. The exclusion of Dark Chestnut soil from the rice turnover contributed to a decrease in humus content by improving the water-air regime and intensifying the organic matter mineralization. In the Dark Chestnut soil of the fallow area, on the contrary, an increase in the humus content and an improvement in its qualitative composition were observed. Keywords: ROSTOV REGION, HUMUS CONTENT, DARK CHESTNUT SOIL, RICE CROP ROTATION, IRRIGATION BY FLOODING