Variability of agrochemical indicators and spring wheat yield in Vysokogorskiy district of the Republic of Tatarstan. Agrobiotechnologies and digital agriculture

An assessment was made based on the retrospective analysis of the content of mobile phosphorus and potassium and spring wheat yield in a time series with the identification of a functional dependence using the example of Vysokogorskiy municipal district of the Republic of Tatarstan for 52 years (1972-2023). The climate in Vysokogorskiy district is moderate - continental. The balance of precipitation and evaporation is characteristic. The soil cover of arable lands of Vysokogorskiy district is represented by gray forest soils and an insignificant proportion of sod-podzolic soils. Over the years of observation, the average weighted content of mobile phosphorus increased in the district, reaching values from 49 in the first cycle to 165.1 mg/kg of soil (fifth cycle). Over 50 years, the concentration of mobile potassium in the soil gradually increased from 110 to 151.4 mg/kg, but by 2023 a decrease to 145.1 mg/kg was recorded. The annual increase was on average 0.77 mg/kg. The simplified balance of nutrients over the years of observation (52 years) has positive values for all the studied nutrients, for nitrogen it is +482.3 kg/ha, the indicators of mobile phosphorus and potassium accumulate in the soils of the district 1019.8 and 553.2 kg, respectively. Since 1972, for 52 years in Vysokogorskiy district, for each hectare of cultivated land, the annual application of mineral fertilizers was 90 kilograms and 4 tons per hectare of organic fertilizers. The use of both mineral and organic fertilizers significantly increased the productivity of spring wheat crops, so from 1972 to 2023, the yield increased by 16.1 centners per hectare. The use of mineral and organic fertilizers ensured a high content of average weighted values of mobile phosphorus (in the range from 51.9 to 157.2 mg/kg), the level of mobile potassium remained at an elevated level (from 96.9 to 145.1 mg/kg). The yield indicators of spring wheat are directly related to changes in the content of available forms of nutrients. Statistical data show a moderate degree of relationship between the indicators (correlation coefficient from 0.61 to 0.67).