Humus content for different use of sod-podzolic sandy soil and the amount of CO2 emissions lost

Abstract

The results of studies of changes of humus content under different soil tillage systems and fertilization of sod-podzolic sandy loam during 4 rotations of grain-sowing crop rotation are presented in the paper and the amounts of CO 2 emission losses are established. Fertilizer systems have been found to have a greater impact on humus content than soil tillage systems. During the 36-year study period, humus loss on a background without fertilizer for plowing a year was 0.13 t / ha, while for fieldless cultivation - 0.11 t / ha. At application of 1 ha of crop rotation area 7.8 t of manure and N 57 P 63 K 70 kg of mineral fertilizers and systematic tillage with rotation of the slice accumulates 0.11 t / ha of humus annually, while for fieldless cultivation - 0.31 t /Ha. It is established that in Polissya zone in sod-podzolic sandy loam soil in rotation with one field of perennial legumes without fertilizer maintenance of deficient humus balance only by reducing the load during the main cultivation is impossible. It was found that during the systematic rotation of fertilizer application during the four rotations of the organo-mineral fertilizer system, grain yields increased on average from 36 to 62%, triticale in the spring by 2.5 times. Against the background of the fertilization system with the elements of biologicalisation (3.9 tonnes of manure + N8 + 1.2 tonnes of straw + 3.3 tonnes of siderata per 1 ha of crop rotation area), on the contrary, crop rotation yields declined mainly by 8-46%. Thus, higher yields from the organo-mineral fertilizer system, as compared to the control, led to more organic feedstock entering the soil for organic matter accumulation and carbon sequestration, which resulted in better humus formation and sequestration of organic carbon. At an average CO 2 emission intensity of 6.3 kg / ha / h. from the soil, during the day the amount of emissions is about 167 kg per 1 ha, and for the whole growing season about 20.1 t / ha of carbon dioxide. Thus, on turf-podzolic sandy loam soils during crop growing, unproductive CO 2 losses range from 2.1 to 4.2 kg / ha / h. Further studies on establishing the role of soil cultivation methods with modern tools in shaping the fertility of Polissya light soils and minimizing the unproductive emission losses of organic matter are promising.