Dependence of agrochemical and agrophysical properties of leached chernozem on soil treatment system

Abstract

The results of research on the dependence of agrochemical and agrophysical properties of leached chernozem on the system of soil treatment are presented. The work was performed in 2015–2019 in a long-term stationary field experiment in crops of spring soft wheat Siberian Alliance. The soil of the experimental site is medium-powered medium-humus heavy-loamy leached chernozem. Wheat was preceded by clean fallow, green fallow (rape), green fallow (cloverleaf). The following tillage systems were studied: deep moldboard (control), deep combined, minimum combined, minimum moldboard. There is an advantage in nitrate nitrogen content in the soil before sowing, in the phase of tillering and earing of wheat on the preceding cereal fallow (rape) when using the minimum tillage system (in autumn the break crop BDT-3 is planted). The effect of the tillage system on the nitrate nitrogen content in the soil in the phase of bushing of wheat - 15,5%, conditions of the year - 12,9, the interaction of these factors - 20,1% was determined. A positive relationship between the content of nitrate nitrogen in the soil and the amount of mobile phosphorus on the precursor green fallow (rape), r = 0.7118-0.8917 (R = 0.9500), was detected. High P2O5 content (from 150 mg/kg and above) was recorded on average for 5 years during the earing phase of wheat - 145.0 to 165.6 mg/kg. Maximum P2O5 values were detected for green fallow (rape) under minimum combined and minimum moldboard systems. A significant increase in exchangeable potassium content over the control average for 2015-2019 was observed with the deep combined tillage system - 5.0 mg/kg (NSR05). With the other tillage systems studied, the figures were at the control level. Higher soil pedality coefficients were revealed with a deep moldboard processing system (control) - 2.54, a minimum combined - 2.47, a minimum moldboard - 2.23 according to the predecessor green fallow (rapeseed); for green fallow (melilot) - 2.98 (deep moldboard). With an increase in the pedality coefficient, there was a decrease in the soil bulk density index, r = -0.3499 (R = 0.5760). A tendency was revealed towards a decrease in the soil bulk density to 0.98 g/cm3 according to the predecessor green fallow (rapeseed) with minimization of soil cultivation: combined moldboard and minimum moldboard; with a deep moldboard (control) - 1.02 g / cm3. As a result of the correlation analysis, it was found that with an increase in the soil bulk density, the content of P2O5, r = –0.4898, K2O, r = –0.2530, decreases.