Conventional tillage increases soil microbial biomass and activity in the Loess Plateau, China

Abstract

Land-use change can affect the quantity and quality of soil organic matter (SOM) as well as soil microbial biomass and activity. Land use in the Loess Plateau has undergone great changes in the past five decades. To understand the effects of these changes on soil chemical and biological properties in the Loess Plateau, we determined soil organic carbon (SOC), total nitrogen (TN), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN), and basal respiration in millet cropland (MC), grazed grassland (GG) and enclosed grassland (EG). Grazing exclusion led to an increase of SOC and TN. Compared with the MC, the two grasslands had higher SOC and TN values in the 0-10 cm layer, but lower values in the 20-30 cm layer. SMBC and SMBN values in the EG were intermediate between the MC and GG. Conversion of cropland to grassland increased soil basal respiration (SR) and metabolic quotient (qCO2), while grazing exclusion resulted in higher SR but lower qCO2. The study suggests that grassland enclosure could increase SOM as well as soil microbial biomass and activity, and conventional cropland might be the optimal land-use type to maintain soil chemical and biological properties in the Loess Plateau, China. © 2013 © 2013 Taylor & Francis.