Changes in the content of soil organic carbon and total nitrogen in the organic and conventional cropping systems

Maintaining and increasing the stock of soil organic carbon is of vital importance in maintaining the soil fertility. In present research the changes in the content of organic carbon (SOC) and total nitrogen (Ntot) in the soil are investigated. The data is collected from the long-term field experiment, which compares organic and conventional farming systems in a crop rotation (barley undersown with red clover, red clover, winter wheat, pea, potato) during 2014–2018. Based on the 5-year experiment, it was concluded that the cropping systems have a significant effect on the SOC content and a smaller effect on the Ntot content of the soil. The diversification of organic cropping systems with cover crops and composted cattle manure significantly increases the content of organic carbon in the soil. The results of the experiment indicate that the content of organic carbon was significantly lower (by 7.6–12.6%) in conventional systems, where pesticides had been applied and cover crops and manure had not been used, compared to the organic cropping systems. The correlations between the SOC contents of main crops and precrops were statistically more significant in organic farming system, compared to the conventional system. Highest SOC and Ntot values were observed in organic systems with cover crops and composted manure fertilization. Hence, it can be stated that in order to improve the soil fertility and fix more carbon and nitrogen, high amounts of organic material should be applied into the soil and the activity of soil microbes should be a priority. The organic cropping systems have more advantages for sustainable crop production.