不同供N方式对大豆生长和结瘤固氮的影响

Soybean(Glycine max L.) Growth and Nitrogen Fixation as Affected by Different N Supplying Modes

采用框栽试验方法对比研究了不同供N方式对大豆生长和结瘤固氮的影响。结果表明:持续供N和非持续供N对大豆生长有不同的影响,在苗期,非持续供N与持续供N相比,对大豆生长有较大的促进作用,而在花期以后则是持续供N对大豆生长的促进作用较大;持续供N和非持续供N对大豆结瘤固氮的影响不同,大豆根瘤数量表现为非持续供N>持续供N>无N,表明氮肥的持续施用对大豆根瘤的形成和生长有抑制作用,不利于大豆根瘤的生长发育;不论何种方式供N对大豆固氮酶活性和豆血红蛋白含量均有抑制作用,使固氮酶活性和豆血红蛋白含量显著降低,而且氮肥的持续施用对固氮酶活性和豆血红蛋白含量的抑制要显著高于非持续供N,表现为持续供N<非持续供N<无N,因此,氮肥的持续施用使大豆的固氮效率降低。

Nitrogen plays an important role in nitrogen fixation of soybean. A pot culture experiment was conducted to study the effect of different N supplying modes （such as continuous N supplying （CN, applied at sowing, seedling, flowering and podding stage,respectively） and non-continuous N supplying （NCN, applied at sowing stage as basal fertilizer）） on soybean gruwth and nitrogen fixation. The results showed that compared with continuous N supplying, non-continuous N supplying acted as higher promotion in soybean growth at seedling stage, however, after flowering stage, continuous N supplying showed higher promotion in soybean grouch. Nodule number showed as following order：NCN 〉 CN 〉 CK, suggested that continuous N application restrained nodule formation and growth. Whether N continuous application or not continuous supplying, nitrogenase activity and leghemogtobin concentration all decreased compared with no N treatment,and the inhibition of N continuous supplying was higher than that of non-continuous N application, showed as continuous N supplying 〈 non-continuous N application 〈 no N treatment. These results suggested that N fertilizer continuous application decreased the efficiency of N fixation in soybean.