玉米-线辣椒套作系统中土壤养分与根际土壤微生物、酶活性的关系

采用玉米单作、线辣椒单作、玉米-线辣椒套作3种栽培模式，并在玉米-线辣椒套作的种间根部设3种不同隔离处理（膜隔、网隔和无隔），研究了玉米-线辣椒套作系统中土壤生物因子与土壤养分的关系．结果表明：玉米-线辣椒套作具有明显优势；与两作物单作和玉米-线辣椒套作种间根区膜隔处理相比，玉米-线辣椒根区无隔和网隔处理复合群体中两作物根际土壤酶活性、微生物数量、土壤养分均显著提高；除有效镁与真菌种群数量、过氧化氢酶活性呈负相关外，其余速效养分与各生物因子均呈显著或极显著正相关．通径分析表明，该系统中促进有机质累积的主要生物因素是脲酶、过氧化氢酶、细菌和蛋白酶，蔗糖酶是影响碱解氮的最主要因子，脲酶是影响有效磷的最主要因子，细菌是影响有效钾的最主要因子，碱性磷酸酶、真菌只是选择性地对有机质的累积和氮、磷、钾有效养分的形成起作用，放线菌对土壤养分的直接作用系数为负，对土壤养分形成的作用较小．

Relationships between soil nutrients and rhizospheric soil microbial communities and enzyme activities in a maize-capsicum intercropping system

By using plastic sheet and nylon mesh to partition the root systems of maize and capsicum in a maize-capsicum intercropping system, this paper studied the relationships between soil biological factors and nutritive status in the intercropping system, with no partitioning and maize monoculture and capsicum monocuhure as the control. The results showed that intercropping maize and capsicum had its high superiority. In the treatments of no partitioning and nylon mesh portioning in the intercropping system, soil enzyme activities, microbial individuals and nutrient contents were significantly higher, compared with those in the treatments of nylon mesh partitioning and monocuhures. All kinds of soil available nutrients showed significant or very significant positive correlations with soil biological factors, except that soil available Mg was negatively correlated with soil fungi and catalase activity. Pathway analysis indicated that in the intercropping system, soil urease, catalase, protease, and bacteria were the main factors affecting the accumulation of soil organic matter, saccharase was the most important factor affecting soil alkali-hydrolyzable N, urease was the most important factor affecting soil available P, and bacteria largely determined soil available K. Soil alkaline phosphatase and fungi selectively affected the accumulation of soil organic matter and available N, P and K. There was a slight negative correlation between soil actinomycetes and soil nutrients, suggesting that actinomycetes had little effect on soil nutrient formation.