不同作物伴生育苗对西瓜根际土壤微生态环境的影响

Effects of Seedling Breeding Accociated with Different Crops on Micro-ecological Environment in Watermelon Rhizosphere Soil

为探明种间伴生改善西瓜根际微土壤生态环境的作用机理,以茼蒿、大葱、小麦与目标作物西瓜同穴育苗,研究伴生对西瓜根际土壤pH值、EC值及微生物、酶活性的影响。结果表明,与单作相比,不同伴生育苗模式均可改变西瓜根际土壤的酸碱性和电导率,促进根际土壤细菌和放线菌的生长,降低真菌数量,改善根际微生物多样性,提高根际土壤脱氢酶、脲酶、转化酶及多酚氧化酶的活性。综合考虑,茼蒿的改良作用明显优于小麦和大葱,其与中晚熟、早熟西瓜伴生后,pH值分别提高69.05%、25.93%,EC值降低47.62%、47.37%;生物多样性指数提高37.77%、11.98%;土壤脱氢酶活性提高105.79%、160.78%,转化酶活性提高24.56%、14.93%,脲酶活性提高15.89%、86.66%,多酚氧化酶提高18.18%、22.83%。相关性分析结果显示,土壤微生物数量与土壤脱氢酶、转化酶和多酚氧化酶活性及其他相关微生物数量之间存在显著相关性。综上所述,茼蒿、大葱、小麦与不同基因型西瓜伴生均提高根区土壤酶活性,改善微生物结构,以茼蒿伴生育苗效果最好;同时,可以通过人为改变土壤相关酶活性调节根际土壤微生物数量和种类以降低西瓜土传病害的发生。

The aim of this study was to explore the mechanism of interspecific association on improving the micro-ecological environment of watermelon rhizosphere soil.Through cultivating seedlings with Chrysanthemum coronarium,Chinese onion and wheat,the effects of associated plants on pH value,EC value,microorganism and enzyme activities in rhizosphere soil of watermelon were studied.The results showed that compared with monocrops,associated with different crops all could change the acid-basicity and electrical conductivity of watermelon rhizosphere soil,promote the growth of bacteria and actinomycetes,reduce the number of fungi,improve microbial diversity,and increase the activities of dehydrogenase,urease,invertase and polyphenol oxidase in rhizosphere soil.Considering comprehensively,the improvement effect of Chrysanthemum coronarium was better than that of wheat and Chinese onion,especially when it associated with mid-late maturity and early-maturity watermelon,the soil pH value increased by 69.05%and 25.93%,the EC value decreased by 47.62%and 47.37%,the biodiversity index increased by 37.77%and 11.98%,the soil dehydrogenase activity increased by 105.79%and 160.78%,the activity of invertase increased by 24.56%and 14.93%,the urease activity increased by 15.89%and 86.66%,and the polyphenol oxidase increased by 18.18%and 22.83%,respectively.Correlation analysis showed that the number of soil microorganisms was significantly correlated with the activities of soil dehydrogenase,invertase,polyphenol oxidase and other related microorganism number.In conclusion,Chrysanthemum coronarium,Chinese onion and wheat associated with different types of watermelon could increase the activities of enzymes in rhizosphere soil and improve microbial community structure,and the effecs of associated with Chrysanthemum coronarium was the best.The number and species of rhizosphere microorganism could be regulated by artificially changing the activities of related soil enzymes so as to reduce the occurrence of soil-borne diseases of watermelon.