作物茬口对连作棉田土壤环境及棉花产量的影响

于2007－2008年在连作8 a的棉田上进行不同作物轮作倒茬田间试验，以研究不同茬口对连作棉田土壤养分、土壤微生物区系以及棉花产量的影响，从而筛选出适宜棉田轮作倒茬的最佳作物茬口。研究结果表明：不同作物茬口的土壤有机质、速效养分含量及棉花产量均高于连作棉田，其中加工番茄茬口对土壤的速效磷含量增加最为显著，小麦、玉米茬口对土壤速效钾含量增加显著；各作物茬口土壤微生物总量均比连作棉田有明显的增加，表现为细菌和放线菌数量增加真菌减少；草木樨、番茄茬口土壤氨化细菌、硝化细菌生理群也明显增加。不同作物茬口的棉花产量表现为加工番茄→棉花＞草木樨→棉花＞小麦→棉花＞玉米→棉花＞棉花→棉花；加工番茄、玉米、小麦可作为连作棉田的良好前茬。

Effects of crop stubbles on cotton yield and soil environment in continuously cropped cotton field

The cotton field continuously cropped for eight years was investigated between 2007 and 2008 in order to find out the effects on soil nutrients, soil microflora and cotton yield with different crop stubbles and the optimum stubbles for cotton. The result revealed that the content of soil organic matter, soil available nutrients and cotton yield with different crop stubbles treatment were all higher than that with continuous cotton cropping treatment, among which processing tomato stubble had a significant increase in soil available phosphorus, while wheat and corn stubbles had a significant increase in soil available potassium. All crop stubbles had apparent increases in the mass of microorganism in soil compared to that in cotton. In general, there was a increase in the number of bacteria and actinomycets, while a decrease in eumyophyta. The volume of ammonibacteria and physiological groups of nitrifying bacteria had significant increases in both sweet clover and processing tomato stubbles. The ranking (high to low) by cotton yield with different crop stubbles is processing tomato, sweet clover, wheat, corn, cotton; and processing tomato, corn and wheat can serve as appropriate interplant stubbles in cotton field.