DYNAMICS OF CO2 PRODUCTION FROM LIMED SOD-PODZOLIC SOIL AT DIFFERENT LEVELS OF SOYBEAN FERTILIZATION

Abstract

In connection with the threat of global warming, one of the urgent tasks of today is the assessment of the intensity of mineralization processes and the study of the carbon cycle in terrestrial ecosystems. The issue of the influence of fertilizer against the background of chemical land reclamation on CO2 emission flows in the crop rotation of Western Polissia is poorly studied and requires detailed analysis. The aim of the study was to determine the CO2 emission intensity from sod-podzolic soil, its concentration in the surface air layer, and the balance of organic carbon at different doses of soybean fertilization against the background of chemical reclamation. Field, agrochemical and statistical methods were used in trial. In variants application of N55Р20K50 and N65Р50K75 with S40 and microfertilizer Nutrivant universal (2 kg·ha-1) on background of 1.0 Hh CaMg(CO3)2 the less concentration of CO2 in the surface layer of the air compared to other variants was observed. That is associated with higher crop productivity. In the branching phase of soybeans, an increase in the emission of carbon dioxide from the soil was noted, the maximum indicator during the growing season was recorded with one-sided application of nitrogen fertilizers N55 – 353 kg/ha/h. In the phase of full maturity, the lowest CO2 emissions and concentration in the surface air layer were noted. The different levels of soybean fertilization at ameliorated sod-podzolic soil caused unproductive CO2 flows in the range from 13.1 to 20.0 t/ha per growing season Correlation analysis showed an inverse relationship between the productivity of the above-ground mass and non-productive losses of CO2 from the soil at R2=0.61. The lowest non-productive CO2 losses of 3.3–3.6 kg/ha/h were in the variants N55Р20K50 and N65Р50K75 with the addition of S40 and microfertilizer on background of 1.0 Hh dose of CaMg(CO3)2. Due to the higher yield of the main and by-products, post-harvest residues, there was accumulation of organic matter and sequestration of organic carbon in the soil at the level of 0.45–0.53 t/ha in that variants.