The Effect Of Intercropping Aromatic Plants On Soil Microorganisms And Carbon And Nitrogen Cycles In The Orchard

This paper was aimed to discuss the effects of intercropping aromatic plants on the soil microorganism community, physical and chemical properties, and soil C and N cycling in the orchard. Tagetespatula L., Satureja hortensis and Ageratum houstonianum were selected as experimental plants. Four experimental treatments, Tagetespatula L.x Satureja hortensis (Trl), Tagetespatula L.x Ageratum houstonianum (Tr2), Satureja hortensis x Ageratum houstonianum (Tr3), and Tagetespatula L.x Satureja hortensis×Ageratum houstonianum (Tr4) were set up, and natural grass (Tr5) were selected as control. We determined the content of soil microorganism community and, soil physical and chemical properties, and soil C and N cycling in soil layers. The results were as follow.1Compared with natural grass plots, mixed intercropping aromatic plants treatments had significantly increased soil moisture and decreased soil pH in0-20cm soil layer under the fruit growing season. The content of soil organic matter, soil major elements (TN, TP, TK, AN, AP, AK) and trace elements (Ca, Mg, Zn, Fe, Cu, Mn) under different treatments showed various trends with the change of developing period.2Compared with natural grass plots, mixed intercropping aromatic plants increased the soil enzyme activity of0-20cm and20-40cm soil layer in young fruit period, fruit enlargement period and fruit maturity period of apple tree, especially the activities of soil catalase and soil urease.3In the two years, compared with natural grass plots, mixed intercropping aromatic plants had significantly improved the number of bacteria, fungi and actinomycetes in0-20soil layer and20-40cm soil layer, improved soil microbial community structure. The FAME content of bacteria, fungi, mycorrhiza, Gram-positive bacteria and Gram-negative bacteria was significantly enhanced under mixed intercropping aromatic plants plots in flowering period, young fruit period and fruit enlargement period.4Compared with natural grass plots, the moisture content, microbial biomass carbon and nitrogen content, microbial C:N ratio, the number of bacteria, fungi, aerobic cellulose-decomposing bacteria and anaerobic bacteria and the invertase and catalase activity had a significantly improve under intercropping aromatic plants plots, and the accumulation of organic carbon content had a significant increase under intercropping aromatic plants plots, which effectively promoted the carbon cycle in the orchard.5Compared with natural grass plots, the number of bacteria, fungi, nitrogen-fixing bacteria, nitrifying bacteria and denitrifying bacteria, the protease and urease activity had a significantly improve under intercropping aromatic plants plots, the accumulation of organic nitrogen and available nitrogen content had a yearly increase, thus effectively promoted soil nitrogen cycle in the orchard.