配施木霉微生物肥对连作黄瓜的影响

Effect of Trichoderma Biofertilizer on Continuous Cropping Cucumber Cultivation with Reduced Rates of Chemical Fertilizer Application

研究减量化肥与哈茨木霉SQR-T037微生物肥配施对盆栽黄瓜产量、品质及土壤有效养分和可培养微生物数量的影响。试验以当地农民惯用化肥施用量的100%作为对照处理(CF),75%的农民惯用化肥量配施普通有机肥(OF)或木霉SQR-T037微生物肥(BF)作处理进行连续盆栽试验。结果表明,75%的农民惯用化肥量配施木霉微生物肥BF与100%的化肥处理CF产量相等且后期有所增产,相对配施普通有机肥处理OF则产量显著提高,同时黄瓜果实中硝酸盐含量降低45%以上,维生素C含量明显增加。此外,BF处理能有效改善土壤养分供应状况,有效磷和速效钾含量明显高于对照CF和OF处理,并显著提高黄瓜根际土壤细菌、有益菌种木霉的数量,维持放线菌数量稳定,且在施用第三季后显著减少真菌数量。因此,减少25%的化肥并配施一定量的木霉微生物肥(50g株^(-1)),不仅能保证黄瓜稳产,还能显著改善黄瓜果实品质,促进土壤中养分的高效利用,节约施肥成本,促进农业可持续发展。

【Objective】The aims of this work were to determine 1）whether reduced rates of chemical fertilizer coupled with PGPM inoculants（Trichoderma biofertilizer）would produce cucumber yield and quality equivalent to those obtained using full rates of chemical fertilizer and 2）how this type of fertilization affects the soil fertility of a continuous cropping system. 【Method】Pot trials were conducted 4 times with a reduced application of chemical fertilizer（75% of the recommended application）plus Trichodermaenriched biofertilizer（BF）or organic fertilizer（OF）,with 100% of the recommended chemical fertilizer（CF）as the control. 【Result】The results showed that supplementing 75% of the idiomatic fertilizer with Trichoderma SQR-T037 biofertilizer（BF）produced yield that was statistically equivalent to or higher than the 100% chemical fertilizer（CF）and increased by 〉21% of yield compared to the OF treatment. This result was consistent across in our previous field experiments,which also indicates that only biofertilizer could be a viable supplementary strategy of fertilizer for maintaining or increasing cucumber yield. Reduced chemical fertilization,both of the BF and OF treatments,resulted in a higher Vitamin C（2%~23% and 35%~54%,respectively）contents in the BF and OF treatments but a lower（32%~46%）accumulation of NO_3^- in the cucumber fruits compared than those of the control（CF）,suggesting that replacing 25% of the chemical fertilizer rates with（bio）organic fertilizer could significantly increase cucumber fruit quality. The application of SQR-T037 biofertilizer（BF）significantly（P〈0.05）increased cucumber rhizospheric nutrient availability. Specifically,the highest contents of available P were more frequently observed in the BF treatment. Moreover,the BF treatment maintained at a higher level of available K compared with that of the CF and OF treatments. Also,the BF treatment significantly increased the population of soil microflora,including bacteria and Trichoderma,maintaining the population of actinomycetes,but with the reduced abundance of fungi,compared with the CF treatment. Based on the explanations known in other researches,the relationship between soil nutrients and microflora in this study may be explained as follows：plant growth might initially be improved by enhanced root growth,which occurs in response to a powerful plant-growthpromoting fungus,T. harzianum SQR-T037,as reported in our previous study. Then,better root growth influences soil microbes via the supply of additional root exudates or rhizodeposition,and soil microbes,in turn,alter plant performance through higher microbial abundance and more frequent interactions resulting in more available nutrients. This process continues in a cycle. More bio-available nutrients promote better root growth,which facilitates more microbial colonization in the rhizosphere,and ultimately results in greater nutrient uptake by the inoculated plants. 【Conclusion】The results of this study imply that the excessive use of expensive chemical fertilizer can be significantly avoided without compromising yield（at least in cucumbers）through the application of a Trichoderma-enriched biofertilizer. Additionally,the use of Trichoderma-enriched biofertilizer with lower fertilizer application resulted in enhanced fruit quality and an improvement in soil fertility and the microbial environment. Therefore,biofertilizer such as this could be used in combination with the appropriate rates of chemical fertilizer and should be applied over a long-term period as a component of integrated nutrient management strategies to obtain maximum benefits in terms of the yield,sustainable use of soil and fertilizer savings.