Intensity of CO2 emissions of sod-podzolic soil depending on fertilization and lime application

Abstract

Topicality. With climate change, agricultural production accounts for about 15 % of green-house gas emissions. Disbalance of organic carbon decreases the environmental sustainability and productivity of agroecosystems and soil fertility. With soil management, the intensity of carbon monoxide emission from the soil can reduce to optimize its organic matter. Issues. There is a crucial need to study and analyze comprehensively the effects of different rates of chemical meliorants and mineral fertilizers for crops in the Western Polissia crop rotation on the volume of CO2 emissions from sod-podzolic soil. Aim. To study the characteristic features of carbon dioxide emissions from sod-podzolic soil during winter wheat and spring barley cultivation with different rates of meliorants and fertilizers. Materials and Methods. Field experiment, agrochemical and statistical methods. Results. On the background of mineral fertilization, land reclamation with limestone materials at 0.5 and 1.0 rates determined by the hydrolytic acidity of the soil generally decreases CO2 emissions into the air. During the growing season, depending on the development stage of spring barley, the level of carbon dioxide emission in the variant with N90P90K90 was 89.8–68.3–63.5 mg CO2/kg soil, and in combination with 1.0 rate of dolomite powder – 83.1–59.8–63.6 mg CO2/kg soil. It is noted that the intensity of CO2 accumulation in the surface layer depended on rates of ameliorant, soil moisture and temperature. Thus, the carbon dioxide emission in a winter wheat field was the highest when 1.5 rates of dolomite powder were applied on the background of N120P60K90 , and in the stem elongation stage at air temperature 13.2 ℃ was 77.7 mg CO2/kg of soil. When air temperature increased to 22.0 ℃ in the heading stage, this indicator increased by 1.2 times and at air temperature of 20.4 ℃ in the full maturity stage, it decreased by 1.3 times. When 1.0 rate of dolomite powder was applied, CO2 emission decreased to 18.2 mg CO2/kg of soil compared with 1.5 rates in the full maturity stage of wheat due to the intensity of redox processes in the soil when different rates of limestone materials was applied. Conclusions. In the short-term crop rotation, lime application had a positive effect on the for-mation of deficit-free balance of organic carbon in sod-podzolic soil with intensive application of mineral fertilizers for crops. When we applied 1.0 and 1.5 rates of dolomite powder on the background of N120P60K90 in winter wheat crops, the organic carbon balance was 0.35–0.28 t/ha, in spring barley crops on the background of N90P90K90 – 0.10–0.16 t/ha. Key words: winter wheat, spring barley, land reclamation, fertilizers, carbon dioxide, balance.