味精废浆对西瓜根际土壤生物学特征的影响

Effects of Monosodium Glutamate Wastewater on Rhizosphere Soil Biological Characteristics of Watermelon( Citrullus lanatus)

为了探讨味精废浆与化肥配施对西瓜根际土壤环境的作用效果以丰乐一号西瓜为试材,通过大田试验,利用平板计数法和末端限制性片段长度多态性分析(T-RFLP)技术,研究了T1(尿素提供100%的氮)、T2(味精废浆和尿素分别提供10%和90%的氮)、T3(味精废浆和尿素分别提供30%和70%的氮)和T4(味精废浆和尿素各提供50%的氮)等处理对西瓜根际土壤微生物数量、微生物量碳和氮、根系分泌物及细菌群落结构多样性的影响。结果表明:与T1处理相比,T3处理显著增加了根际土壤细菌数、放线菌数、微生物总量及微生物量碳、氮含量,而对真菌数的影响较小,其中细菌数、微生物量碳和氮含量分别增加53.59%、39.80%和45.59%;明显提高了根际土壤中根系分泌物含量。同T3处理相比,T2和T4处理对根际土壤微生物数量及根系分泌物含量的影响较小。此外,T3处理的细菌群落结构的丰富度及多样性指数最高,分别比T1处理提高91.79%和97.31%,差异达显著水平(p<0.05);同时也明显高于T2处理,但与T4处理差异不显著。综合分析认为,配施味精废浆可有效改善西瓜根际土壤的微生态环境,而味精废浆与化肥的搭配比例是关键因素。

A field experiment was conducted by using the traditional plate count method and modern terminal restriction fragment length polymorphism （T-RFLP） method for exploring the effect of monosodium guhamate wastewater co-applied with inorganic fertilizer on the ecological environment of watermelon rhizospher soil. The present study was conducted to determine the effects of different treaments. Purpose of the study was to evaluate the effects of different treatments, i. e. T1 （100% of nitrogen was provided by urea）, T2 （10% and 90% of nitrogen was provided by monosodium glutamate wastewater and urea, respectively）, T3 （30% and 70% of nitrogen was provided by monosodium glutamate wastewater and urea, respectively） and T4 （50% and 50% of nitrogen was provided by monosodium glutamate wastewater and urea, respectively） on microbial populations, contents of microbial biomass carbon （MBC）, microbial biomass nitrogen （MBN） and root exudates, as well as bacterial community structure diversity in the rhizosphere soil of watermelon. The results indicated that comparison with T1 treatment, T3 treatment significantly increased the numbers of bacteria, actinomycetes and total microorganism, as well as MBC and MBN contents in the rhizosphere soil, showing 53.59% , 39.80% and 45.59% increases in bacteria populations and contents of MBC and MBN, respectively, while it had no significant influence on fungus populations. At the same time, T3 treatment obviously increased the root exudates contents in compared with T1treatment. However, in T2 and T4 treatments, less effect on microbial populations and root exudates contents was observed than that in T3 treatment. In addition, a significant difference was found in T-RFLP profiles of different treatments. T3had the highest shannon index and margalef index, which were increased by 91.79% and 97.31% compared to T1 treatment, respectively. In the meantime, the shannon index and margalef index in Tz treatment were obviously higher than those in T2 treatment, but had no significant difference with T4 treatment. In conclusion, monosodium glutamate wastewater co-applied with inorganic fertilizer can improve the ecological environment of watermelon rhizosphere soil, and the collocation proportion between monosodium glutamate wastewater and inorganic fertilizer is the vital factor.