| The extensive use of pesticides,mulch and chemical fertilizers in the production of installment agriculture has led to environmental pollution,residue of mulching films and degradation of cultivated land quality,limiting the improvement of regional soil quality and sustainable agricultural development.The application of green agricultural inputs,such as biodegradable mulch,plant immune attractants and new fertilizers,can play a positive role in solving these problems and is a key measure to ensure the development of agricultural production in an ecologically efficient direction.Based on this,the present study was conducted to investigate the effect of immune attractant on plant growth and disease resistance,the degradation performance of biodegradable mulch film,and the effect of cross-combination of agricultural green inputs(new fertilizers,plant immune attractant and controllable degradable mulch film)on the yield,quality and soil quality of peppers in greenhouse,with a view to providing guidance for the application of agricultural inputs in greenhouse vegetable production and the comprehensive improvement of greenhouse soil quality.The main results are as follows.(1)A pot experiment was conducted to study the effect of immune inducer ZNC on growth and disease resistance of pepper as a test crop.A two-factor experimental design including three levels of ZNC concentration(0,5 and 20 ng/m L)and two levels of Ralstonia solanacearum(Rs)inoculation(inoculation and no inoculation)was adopted.It was found that root application of ZNC(especially 5 ng/m L ZNC)could increase the biomass of pepper plants and promote root growth.Compared to 20 ng/m L,root application of 5 ng/m L ZNC was more effective in improving photosynthetic performance(net photosynthetic rate,transpiration rate and chlorophyll content increased by an average of 21.59%,42.69% and16.13%,respectively)and antioxidant enzyme activities(especially catalase activity increased by an average of 32.90%)of pepper;meanwhile,root application of 5 ng/m L ZNC significantly increased the resistance of pepper to bacterial wilt,while 20 ng/m L ZNC did not show this effect.(2)The changes in microstructure,morphology,and mechanical strength of biodegradable mulch films under greenhouse conditions were investigated,using ordinary mulch films as a control.Fourier transform infrared spectroscopy showed that the physical and chemical properties of ordinary mulch films did not significantly change during the 210 day mulching period,indicating that no degradation occurred.The biodegradable mulch film did not undergo visible degradation before 150 days,but the scanning electron microscope images showed that irregular protrusions and depressions appeared on the surface of the film after 90 days of mulching,fine cracks began to appear after 150 days,fine cracks began to increase after 180 days,and the crack width increased to ～3μm after 210 days.The mechanical property tests showed that the elastic modulus,elongation at break,tensile strength,and tensile breaking stress of the biodegradable mulch film after 210 days mulching were reduced by 69.76%,89.00%,50.40%,and 96.63%,respectively,compared to 0 days.Both the microscopic appearance and mechanical property tests showed that the biodegradable mulch film had a degradation behavior during the growth period of greenhouse pepper.(3)Through conducting a plot experiment on optimizing the combination of green inputs,it was found that the use of green agricultural inputs such as biodegradable mulch film,new fertilizers(humic acid compound fertilizer,bio-organic fertilizer,soil conditioner)and immune attractant had positive impacts on the yield,quality of pepper and the physical,chemical and biological properties of the greenhouse soil: compared to the conventional control,the yield of peppers treated with green inputs increased by 2.70%-12.73%,vitamin C by 18.55%-176.85%,and soluble sugar by 8.04%-41.84%;meanwhile,the diversity of bacteria and fungi and the relative abundance of dominant bacterial groups in soil increased.Based on principal component analysis to evaluate and analyse the soil fertility of different green input combination treatments,it was found that the soil fertility quality index of the green input treatments all improved compared to the conventional control(soil fertility index0.185),with the highest soil fertility index of 0.791 and 0.787 for the agricultural green input combination "biodegradable film + new fertilizer" and "biodegradable film + new fertilizer +immune attractant",respectively.The study found that the application of green inputs such as biodegradable mulch film,plant immune attractant and new fertilizers can not only promote the growth of pepper and improve the yield and quality of pepper in greenhouse,but also improve the fertility quality of greenhouse soil,which is conducive to green and sustainable agricultural development and should therefore be vigorously promoted. |
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