氮肥及秸秆有益于提高设施番茄土壤芽孢杆菌及假单胞菌的种群数量

摘要

Root zone N management can reduce N fertilizer input and avoid nitrate pollution in greenhouse tomato production; however, little information is available on how reduced N affects soil microbes, especially dominant bacteria populations in long-term continuous greenhouse systems. This study investigated the effects of different combinations of N and straw on the population size of soil total bacteria and two dominant bacteria (Pseudomonas spp. andBacilusspp.), and microbial community structure in a 6-year greenhouse tomato trial. The treatments were basal fertilizer (10 t ha-1 chicken manure; control), conventional high N treatment [600 kg N ha-1], conventional high N treatment with wheat straw, reduced N treatment [300 kg N ha-1 less than conventional], and reduced N treatment with wheat straw. Six years of reduced mineral N fertilization did not lead to a decrease in fruit yield. Both mineral N fertilizer and straw increased the numbers of soil bacteria (Bacilus spp. andPseudomonas spp.) compared with the control, but the numbers were not affected by the amount of mineral N fertilizer (highvs reduced). Different denaturing gradient gel electrophoresis patterns were evidence that soil bacterial communities were changed by N treatments and straw application, but little difference in bacterial diversity was detected between high N and reduced N treatments. These results indicated that a reduction in N fertilizer input was possible in greenhouse tomato production and was beneifcial in sustainable agriculture.%设施番茄根层氮素管理可以有效减少氮肥的用量及避免硝酸盐污染，但是在设施番茄生产中减少氮肥用量对土壤微生物，尤其对优势菌群有何影响目前还知之甚少。本文以6年定位试验中不同氮肥用量及秸秆处理的设施番茄连作土壤为研究对象，研究不同氮肥用量及秸秆处理对土壤细菌和两种主要细菌（假单胞菌及芽孢杆菌）以及对土壤微生物群落结构的影响。设置如下处理：对照（10 t ha-1鸡粪作为底肥）、传统高氮处理（600 kg N ha-1）、传统高氮+小麦秸秆处理、减氮处理（300 kg N ha-1）及减氮处理+小麦秸秆处理。研究结果表明，6年减氮处理并未导致番茄减产；与对照相比，化学氮肥及秸秆的施用均显著增加了土壤细菌、芽孢杆菌及假单胞菌的数量，但不同氮肥用量之间对土壤细菌、芽孢杆菌及假单胞菌数量的影响无显著性差异。DGGE图谱表明氮肥用量及秸秆添加导致土壤微生物群落结构的改变，但不同氮肥用量对土壤细菌多样性的影响不显著。本研究结果表明减少一半氮肥用量既不会导致减产，也不会对土壤微生态环境产生不利影响，因此，在该试验条件下减少氮肥用量是可行并且有益于农业可持续发展的举措。