Impact of Crop Diversity, Fertilization and Legumes on Soil Organic Carbon in Grasslands

Agricultural soil quality is decreasing as a result of the expansion and intensification of agriculture. A key indicator of soil quality is soil organic carbon (SOC) which is degraded when land is converted from natural to cultivated systems and subject to intensive agricultural land use, reflecting reduced soil fertility and productivity. The aim of this study was to examine the effect of crop diversity, fertilizing levels and legumes on SOC accumulation in 3-year-old perennial production grasslands in Alnarp, Sweden. Since the soil was assumed to have a negligible content of inorganic (pH < 7), total carbon was used as an estimate of SOC. No significant differences in SOC depending on crop diversity, nitrogen fertilization treatment or presence of legumes were identified. The absence of significant differences was potentially due to local soil heterogeneity, where SOC was significantly dependent on the positioning within the researched blocks in the field, rather than on treatments. By examining how agricultural land management affect SOC contents in arable lands, methods enhancing soil C accumulation can be developed and improved, leading to extended agricultural soil quality and food production.