Phosphorus-potassium state as an element of natural fertility of gray forest soils of Western Siberia

Abstract

The purpose of the study was to assess the availability of phosphorus and potassium mobile forms in the humus layer of virgin gray forest soils in the western part of the West Siberian Lowland. The results of laboratory tests were processed using mathematical methods of variational statistics in Microsoft Excel. It was revealed that gray forest soils have low availability of mobile phosphorus in the humus layer (light gray - 34±17 mg/kg, gray - 44±23 mg/kg, dark gray - 52±24 mg/kg of soil). For that reason, when they are involved in arable land, continuous phosphorization or constant application of phosphorus fertilizers will be required. Also, during agricultural use, a high degree of variation in the content of mobile phosphorus should be considered (variation coefficient is 45% for dark gray and 51% for light gray and gray forest soils). Gray forest soils are characterized by a fairly good supply of mobile potassium, which content in humus layer of light gray soils is 133±45 mg/kg, gray - 140±49 mg/kg, dark gray - 164±51 mg/kg of soil. This is due to the peculiarities of the mineralogical composition of parent rock materials of gray forest soils. The variation of the content of potassium mobile forms in all subtypes is estimated as average. The research results can be applied in the development of agrochemical measures aimed at increasing the fertility of gray forest soils.