INFLUENCE OF BASIC TREATMENT TECHNIQUES OF FALLOW FIELDS ON THE NITRATE NITROGEN REGIME IN AGROCHERNOZEM

The purpose of the study is to evaluate the influence of methods of basic treatment of fallow fields on the regime of nitrate nitrogen in the agrochernozem of the Krasnoyarsk forest-steppe. The studies were conducted in 2013–2015 in a field experiment in the conditions of the Minino station of the Krasnoyarsk Research Institute of Agriculture, located in the Krasnoyarsk forest-steppe. The objects of the study are cryogenic-mycelial thin agrochernozem, medium-loamy, and fallow fields of five-field field crop rotation (fallow – wheat – rapeseed – barley – oats). An assessment is made of the influence of methods of basic treatment of fallow fields on the nitrate nitrogen regime. The study was carried out on three blocks of main soil cultivation: 1 – moldboard cultivation (plowing black fallow PLN-4-35 to a depth of 20–22 cm); 2 – minimal shallow cultivation (autumn disking of black fallow with a Rubin 9600KU cultivator to a depth of 10–12 cm); 3 – zero treatment (chemical fallow). Soil samples were taken in layers of 0–10, 10–20 cm. The sampling periods were June, July and August. In mixed soil samples composed of 10 individual samples, nitrate nitrogen was determined using an ion-selective electrode. It has been established that moldboard plowing and minimal shallow cultivation of fallow fields form a very high (21 mg/kg) and increased (15 mg/kg) supply of nitrate nitrogen to the 0–20 cm layer of agrochernozem. Under conditions of zero tillage of fallow fields, the level of nitrate nitrogen supply on average during the study period was estimated at an average level (10 mg/kg). Differentiation was noted in the 0–20 cm layer of agrochernozem with the accumulation of nitrate nitrogen in the 10–20 cm layer, depending on the treatment method. The difference between the layers of 0–10 and 10–20 cm of agrochernozem in N-NO3 content was 4 mg/kg during plowing and 3 mg/kg during no-tillage.