| 【Objective】The study aims to explore the effects of Indigofera spicata on weeds, soil nutrient content and soil diversity in 0~20 cm soil layer after planting in citrus orchards for one year.【Method】Four different treatments were set up: naturally growing grass (CK1), soil covered with grass repellent cloth (PD1), soil covered with silver-black plastic film + planting Indigofera spicata (PD2), and planting the Indigofera spicata (PD3). After one year of planting, weed species were investigated, soil physicochemical properties (pH, organic matter, total nitrogen, alkali-hydrolytic nitrogen, total phosphorus, available phosphorus, total potassium and available potassium) and soil bacterial community were determined.【Result】The contents of total nitrogen (0.86 mg/g), total phosphorus (0.78 g/kg), available phosphorus (23.84 mg/kg), total potassium (11.91 g/kg) and organic matter (34.82 g/kg) in soil treated with PD2 were the highest. Compared with PD1 treatment, the total nitrogen content and alkali-hydrolyzable nitrogen content of PD2 treatment increased by 0.37 mg/g and 27.43 mg/kg, respectively. The content of total phosphorus in soil treated with PD1 was the lowest (0.41 g/kg), and the contents of available phosphorus (10.67 mg/kg) and organic matter (25.99 g/kg) were the lowest in the PD3 treatment. The soil total potassium content of PD1-PD3 treatments was greater than that of CK1 treatment, while the available potassium content showed the opposite result. The weed survey results showed that both PD1 and PD2 treatments could well inhibit the growth of weeds. Compared with CK1, treatments PD1-PD3 could reduce the diversity of bacterial communities, but do not affected the uniformity of bacterial community distribution. The soil bacterial community structure and abundance of PD2 and PD3 treatments were similar, which showed that the relative abundance of Proteobacteria decreased; the relative abundance of beneficial bacteria such as Chloroflexi,Acidobacteria,Planctomycetes, Rokubacteria and Gemmatimonadetes increased; among them, the dominant bacterial genera treated with PD2 were MND1 (3.47%), Sh765B-TzT-35 (4.37%), and the dominant bacterial genus treated with PD3 was MND1 (4.29%). Deinococcus-Thermus (5.10%) regarded as a marker of soil environmental deterioration was detected in PD1-treated soil.【Conclusion】Citrus orchard pavement covered with plastic film and then planted with the Indigofera spicata shows the best comprehensive performance, which can increase soil nutrients and the relative abundance of beneficial bacteria communities. |
