“黑麦草-水稻”草田轮作系统根际效应研究Ⅳ.黑麦草根际土壤性状及其对水稻幼苗生长的影响

探讨了黑麦草Lolium multiflorum根际非根际土壤性状差异以及对水稻幼苗生长的影响,土壤分析表明:根际比非根际土壤的pH值低1.6%,而土壤电导率高19.3%,根际土壤多糖、酒石酸、苹果酸、乙酸、柠檬酸、琥珀酸含量分别比非根际土壤高9%、12.5%、8.3%、24.4%、12.5%、7.7%;土壤微生物的差异更为明显,细菌、放线菌和真菌分别高12倍、3.1倍和9倍,同时,根际土壤中的酶活性也比非根际土壤强,其中土壤脱氢酶、蛋白酶、磷酸酶、脲酶活性分别高37.1%、36.5%、70.6%、35.7%.水稻幼苗盆栽试验表明,在不同施肥条件下,根际土壤栽培的水稻幼苗的株高、单株叶面积、地上部地下部干物质积累量、根长、根数、叶片叶绿素质量分数和根系活力均不同程度地高于非根际土壤.可见,黑麦草的根际效应对于改良稻田土壤理化和生物性状有重要的作用,并有利于后作水稻幼苗的生长.

Rhizosphere Effects in "Ryegrass-Rice" Rotation System Ⅳ. Properties of Rhizosphere Soil of Italian Ryegrass and Its Effects on Growth of Rice Seedling

Soil properties in rhizosphere and non-rhizosphere of Italian ryegrass ( Lolium multiflorum) were analysed and gworth of rice ( Oryza sativa) seedling on the two soil were compared. The results showed that pH value was lower and EC was higher in the rhizosphere than in the non-rhizosphere for 1.6% and 19.3%, respectively. Concentrations of polysaccharide, tartaric acid, malic acid, acetic acid, citric acid, succinic acid in the rhizosphere were higher than in the non-rhizosphere for 9%, 12.5%, 8.35, 24.4%, 12.5% and 7.7%, respectively. In the rhizosphere soil, the numbers of bacteria, actinomyces and fungi were 12, 3.1 and 9 times of those in the non-rhizosphere soil, and the differences were all significant (P < 0.01). The enzyme activities of dehydrogenase, protease, phosphatase and urease were also higher in the rhizosphere than in the non-rhizosphere for 37.1% , 36.5% , 70.6% and 35.7% , respectively. Correspondingly, seedling of rice cultured in the rhizosphere soil grew well when compared with those in the non-rhizosphere. The trends being higher in the rhizosphere than in the non-rhizosphere were observed in almost all tested characters for the seedling, including plant height, leaf area per plant, chlorophyll content, the biomasses of shoot and root, root length, root number and root activity. It is suggested that the rhizosphere effect of Italian ryegrass plays an important role for improving the chemical, physical and biological properties of paddy soil, and it shall be benefit for growth of seedling of subsequent rice.