Effects Of Potato Continuous Cropping And Intercropping Regulation On Rhizosphere Soil

Aimed at the wide spread phenomenon that potato continuous cropping obstacles in south of Ningxia province because of its wide planting, the change of soil fertility and microorganisms’structure; and the action mechanism of intercropping regulation systems of potato/corn, potato/broad bean and potato/buckwheat on potato’s continuous cropping obstacles were studied in an angle of change of diversity of microorganisms’ structure and function by using field experiment combined with analysis indoors(normal way of studying soil chemical characteristics, PLFA,16S rDNA PCR-RFLP). The main results showed:1. Potato’s continuous cropping can make pH high, but didn’t make the soil fertility drop. It changed the microbial nitrogen and enzymes, making catalase, urease, phosphatase and microbial nitrogen rise first and then down along with the years.2. Sustainable continuous cropping can make soil microorganisms prefer carbohydrate, then amino, and had a weak intensity in using polymers and amine. T-RFLP showed, there were70,56,10bacterial species in soil of continuous cropping for2years,6year and10years. The yield of potato dropped along with the years too.3. After intercropping, the pH had a drop trend in different treatments. Potato intercrop with corn, broad bean and buckwheat reduced soil total phosphate, available phosphate and available potassium0.11～0.49g·kg-1、0.44～0.47g·kg-1、76.56～89.91mg·kg-1、59.86～192.6mg·kg-1respectively than CK, available phosphate had the most amplification which is more than45%.4. We found syntrophomonas (kind of bacteria produce acid alone and can making fatty acid and alcohol transferred into and acetic acid and nitrogen along with dark coli and fusobacterium etc.)by using T-RFLP. And it can change along with the change of pH. Intercropping can change the species number from34when continuous cropping to43, showing intercropping can rich the diversity of microorganism’s structure and inheritance, making a sustainable ecological environment of biota.5. The yield in each block showed, Intercropping with broad bean can increase the yield of potato in per cropping area, but not intercropped with corn and buckwheat. It can significant increase microorganisms’ ability in utilization of carbon source, enriched the diversity of structure and function and can maintain a stable yield, so it can be treat as a intercropping types in improving the microbial environment and remittance the potato cropping obstacles.