Abstract
The article presents the results of studies on correlations between the productivity of sugar beets and phosphorus, mineral and organic phosphates of soil grown in monoculture conditions and crop rotation on irrigated dark chestnut soil. Fertilizer application in a monoculture increases the amount of mineral phosphates in the range of 691,1-791,2 mg/kg, organic phosphates by 293,2-372,0 mg/kg, and under crop rotation conditions these indicators are 567,4-775,9 mg/kg and 332,5-395,8 mg/kg, respectively. It has been established that the correlations between the yield of sugar beets grown under conditions of monoculture and crop rotation, and mobile phosphorus and “active” calcium phosphates (Ca-PI + Ca-PII) in the soil are very high and amount to: R = 0,97-0, 99 and R =0,98. The correlations between sugar beet yield and organic phosphate phosphorus (LOS, fulvo and humic acids) were insignificant compared to mineral phosphate phosphorus. Under monoculture conditions, a high correlative relationship R = 0,81 was determined between the phosphorus of loose organic substances and the yield of sugar beets, and in crop rotation - between the phosphorus of fulvic acids and the yield of sugar beets (R = 0,76).