【摘要】 以湖南省长沙地区发育于第四纪红土上的红壤性水稻土为材料,用淹水密闭培养法、生物法以及化学测定法等研究了不同稻作制对红壤性水稻土氮矿化特性的影响。结果表明,在不同稻作制之间,氮矿化势、有机质、全氮、水解性有机氮、易矿化氮,叶绿素类化合物含量及谷氨酰胺酶,天门冬酰胺酶活性大小具有一致的变化趋势,即稻—稻—冬泡>稻—稻—绿肥>稻—稻—油菜;氮矿化势与土壤有机质、全氮、水解性有机氮之间呈极显著正相关;易矿化氮与叶绿素类化合物含量之比近于常数;酰胺酶活性与水解性有机氮之间也呈显著正相关:水稻吸氮量与氮矿化势之间呈极显著正相关,以培养法测得的氮矿优势比其它几种化学法测得的氮矿化势指标作为水稻土供氮能力的指标要好。更多还原

【Abstract】 The study was conducted with the methods of submerged incuba- tion, extraction by chemical reactants and rice absorption. The mineralization- time curves conformed to zero-order and first-order dynamic equations and cumula- tive temperature model. The main results were summarred as follows: 1. The N mineralization-time curves of all tested soil satisfied quite well the zero-order and first-order dynamie equations and cumulative temperature model at α=0.01 or α=0.05, with the cumulative temperature model being best fitted. 2. The mineralization rate constant and K of the tested soils were not affected by the histories of various rice-based cropping systems but the three main systems in order of increasing potentially mineralizable N and N₀ were early rice-late rice- winter flooding （ELF）, early rice-late rice-winter green manure （ELG） and early rice-late rice-winter rape （ELR）. 3. The main source of N₀ was the hy- drolyzable organic N and the amount of stable organic N was the largest in ELR system and then came ELG system and ELF System. 4. In order of decreasing amonnt of chlorophyll-type compounds in soil,the three systems were ELF,ELG and ELR, while the ratio of mineralizable N（MN） to chlorophyll-type compo-unds was neariy constant with slight increase under aerobic conditions. 5. In order of decreasing activities of glutaminase and asparaginase in soils,they were ELF,ELG and ELR, while the two activities were correlated with the hydroly-zable organic N significantly. 6. pot experiment showed that in order of decre-asing N uptake by rice plant, they were ELF, ELG and ELR and N uptake by rice plant was correlated with two N₀ indices significantly.更多还原