| The composite application of biocontrol agents and straw is widely used in winter greenhousecultivation in northern China. It can heighten soil quality, reduce disease, improve the vegetables’quality, increase production, and have many other effects. To explore whether corn stalk degradationintensified by biocontrol microbes technology can influence the rhizosphere microflora fertility and soilhealth indicators in cropping facilities vegetable soil, the research used plate culture count combinedwith end-labeled restriction fragment length polymorphism (T-RFLP) analysis to detect the dynamicvariation of biocontrol agents and pathogens in the soil during facility vegetable cropping, the dynamicvariation of the microbial indicators; and detected the dynamic changes of soil fertility indicators;investigated soil-borne diseases and vegetable production traits after this Treatments. The results are asfollows:1. During continuous cropping, there is no difference in the content of Phytophthora capsici in pepperphytophthora blight nursery after composite application of biocontrol agents and straw, comparing withthe control. In cucumber mixed nursery, the number of Fusarium oxysporum had slower growth rateafter the second stubble, comparing with other treatments and blank control; the number of pathogenicnematodes showed no change compared with blank in the first crop, and was reduced by35.55%afterthe second stubble. The number of parasitic nematodes in cucumber nematode disease nursery wasreduced by20.2%in the first stubble,26.3%in the second stubble, and61.7%in the third stubble. Afterthe treatment of composite application of biocontrol agents and straw, the content of Purpureocilliumlilacinum in pepper phytophthora blight nursery was gradually increased; and it increased by25.4%atthe second stubble. In cucumber compound disease nursery, the number of P. lilacinum and Bacillussubtilis was relatively stable after composite application of biocontrol agents and straw treatment in thesecond crop. The number of P. lilacinum and B. subtilis increased significantly after the compositeapplications of biocontrol agents and straw in the first two crops in cucumber nematode disease nursery.2. By the treatment of composite applications of biocontrol agents and straw, the number of bacterialand fungal ratio (B/F) decreased in the second crop in pepper disease nursery; but there was nosignificant difference between the stubble. In cucumber composite disease nursery and cucumbernematode disease nursery, the B/F values were the highest in the second stubble. The number ofactinomycetes put little change during continuous cropping.3. The diversity analysis of soil bacteria T-RFLP diversity showed that, with the compositeapplications of biocontrol agents and straw, the richness, dominance, diversity and evenness indiceswere increased significantly both in the second crop in the cucumber mixed nursery and pepper blightnursery; and it also promoted the content of TRF139fragment of beneficial flora in a significant roleand inhibited the TRF122, TRF341and TRF501fragment of harmful flora.4. After composite applications of biocontrol agents and straw in these three nurseries, the content oforganic matter and hydrolysable N had improved significantly, there was little change in content ofavailable phosphorus and potassium.The activity of soil enzymes was stable during continuous cropping. Soil pH did not change significantly during continuous cropping. Compared with CK, soil bulk densitywas reduced by11.1%with the corn stalk degradation intensified by biocontrol microbes technologytreatment in pepper nursery3.7%in cucumber mixed nursery, and20.0%in cucumber worm diseasenursery.5. Disease index was reduced by22.2%, after composite applications of biocontrol agents and strawin the third crop in cucumber mixed nursery, and was reduced by2.22%compared with the control inthe second crop in cucumber nematode disease nursery. The yield was increased by58.3%and4.6%inthe first and second crop respectively. From the first crop to the third crop in cucumber mixed nursery,the yield in this treatment was increased by62.3%,29.6%and25.9%; while45.1%,35.0%and25.9%in cucumber worm disease nursery.The results showed that, the composite applications of biocontrol agents and straw can inhibit theincrease of pathogens number effectively in the soil during continuous cropping; the soil can transformfrom fungal disease soil to the type of bacteria healthy soil, and it can also improve the soil bacteriadiversity effectively, promote the growth of beneficial bacteria, and inhibit harmful bacteriasignificantly; besides, it can improve soil fertility and physical properties, reduce the occurrence ofdisease, as well as promote crop growth and increase the yield of vegetable. |
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