The management of microbiological regime of the irrigated light chestnut soils in the Nizhnee Povolzhye under drip irrigation

Abstract

There is a certain relation between soil fertility and its microorganism content. The article considers the microbiological characteristics of irrigated light chestnut soils in the Nizhnee Povolzhye on various media. The soil samples were taken in the plow horizon (0-20 cm) in five replications for each experimental variant. To determine and account for the microorganism groups in the studied soil, the following nutrient media were used: MPA (meat-and-peptone agar), Wort – Agar and Czapek’s, Waksman’s. The studies also included the determination of the nutrient content in the soil in order to adjust the fertilizer application system for drip irrigation, since the soil arable layer on the experimental plot was poorly provided with easily hydrolyzed nitrogen and exchangeable potassium, and in medium way with mobile phosphorus. On the irrigated area one selected the plots with onion and cucumber crops with different mineral nutrition and the levels of maintaining pre-irrigation soil moisture, as well as a variant with a virgin (nonirrigated) plot. The development features of microbial communities on irrigated and non-irrigated lands were revealed. In the arable layer of the irrigated light chestnut soil of the Volgograd region, a fungus of the genus Fusarium, bacteria Bacillus subtilis, bacteria of the genus Erwinia were found, which can make it difficult to grow and store agricultural products. The options for maintaining pre-irrigation soil moisture during drip irrigation of vegetable crops did not have any significant effect on the quantitative and qualitative composition of microorganisms. The studied soil, according to agro-chemical analysis, is fertile and can be used for crop growing. Crop cultivation on non-irrigated areas should be carried out with the application of appropriate fertilizers.