Effect of leguminous cover crops on soil biological activity in pots of Citrus unshiu Marcovitch

Little is known about the effects of cover crops on soil properties in citrus orchards. To fill this gap, this work was aimed to determine the effects of leguminous cover crops on the chemical and biological properties of the soil and on the structure of the microbial community in pots of Citrus unshiu (Marcovitch). After amendment with cover crops, an increase in total organic C (TOC), total extractable C (TEC), and total N (TN) contents were observed irrespective of the type of soil. Substrate induced respiration (SIR), and potentially mineralisable nitrogen (PMN), tested three times in one year, were higher in soils with leguminous cover crops while no significant differences were observed in protease and deaminase activity. The effect on the chemical and biochemical properties of the soil was more evident in plots containing Trifolium subterraneum. No changes were observed in the microbial communities studied (α-proteobacteria, β-proteobacteria, nitrogen-fixing, and ammonia oxidizers) irrespective of the kind of cover crop or type of soil, neither were variations noted during the trial.