Effect of humate substances on biological activity and physical properties of eroded soils: a case study of Uzbekistan

Abstract

Worldwide, approximately 3 million hectares of land degraded due to erosion, and every minute approximately 44 hectares of agricultural land are being lost. In fact, agricultural area situated in arid zone is vulnerable to erosion, which leads to decline in agricultural productivity due to low quality soil. Evidently, the vital activity of microorganisms is interlinked with the assimilation of minerals by plants in irrigated lands, that is, the production of high and quality crops. Therefore, this research was intended to see effect of humate substance on biological activity and physical properties of eroded soils, that is, investigate how humate substance impact on overall structure of soils in the Pskent district of Tashkent province. The results extracted from field and laboratory experiments showed that poultry manure in moderately eroded soils and humus and poultry manure variants in washed-out soils ranged from 2.2x107 KHB/g to 7.5-3.0x106 KHB/g. Oligonitrophilic microorganisms were found to be the same in all variants. Micromycetes were observed in humus variants with an average erosion of 2.2x104 KHB/g, and in washed-out soils of 7.5x103 KHB/g. The amount of actinomycetes in samples 3 and 4 was 7.5x103 KHB/g per 1 gram of soil, while in samples 1, 2, 5 and 6 they were not found at all. This means that the amount of actinomycetes was slightly reduced in summer, but the relative changes between the options were 1.1-8.3x108 KHB/g in washed-out soils with moderate erosion in less washed soils, and 7.5-8.3x107 KHB/g in moderately washed and washed soils. Furthermore, influence of humic biofertilizers, organic fertilizers on general physical properties of eroded typical gray soils was also studied. Accordingly, the effect of fertilizers in the control variant was 1.30g/cm3, followed by the variant with the use of mineral fertilizers humate 1.27g/cm3, and the application of poultry manure 1.29g/cm3. In moderately eroded soils, the values were found to be 1.40 g/cm3, 1.35 g/cm3, 1.33 g/cm3, respectively, and 1.25 g/cm3, 1.31 g/cm3, 1.29 g/cm3 in washed out soils.