以湖南、湖北和山东烟区的主要植烟土壤为研究对象,采用Warning淹水培养方法,研究了不同类型土壤的氮素矿化过程.结果表明,淹水培养0～14 d为土壤铵态氮含量快速增长期,培养14 d的土壤铵态氮含量显著高于培养始期,土壤氮素矿化速率为正值,表现为氮的矿化.15～28 d土壤铵态氮含量变化较小.28 d后土壤铵态氮含量逐渐降低,各阶段的土壤氮素矿化速率为负值,表现为氮的固定.在氮素矿化阶段,土壤铵态氮含量表现为水稻土>黄棕壤(南漳)>黄壤>黄棕壤(利川)>红壤、褐土.在整个培养过程中,水稻土的铵态氮含量最高,棕壤和褐土的铵态氮含量最低,说明水稻土的氮素供应能力较高,棕壤和褐土的氮素供应能力较低.回归分析表明,培养7、14、21和28 d的氮累积矿化量与土壤有机质含量和全氮含量呈极显著或显著正相关关系,说明有机质和全氮含量是评价土壤供氮能力的有效指标.%In order to investigate the organic nitrogen mineralization of tobacco-growing soils, six typical tobacco-growing soils:Paddy soil (sampled from Shaoyang), Yellow brown soil from Nanzhang, Yellow soil (sampled from Shaoyang), Yellow brown soil from Lichuan, Red soil (sampled from Nanzhang) and Cinnamon soil (sampled from Yishui), were chosen to measure the nitrogen mineralization by using the Warning incubation method.The soils were waterlogged for 56 days.The results indicated that soil ammonium nitrogen showed a tendency to increase sharply, change gently and then decrease significantly during the incubation period.The soil ammonium nitrogen increased rapidly and soil nitrogen mineralization rate was above zero from 0 to 14 days after incubation (DAI), represented as mineralization of soil nitrogen, and the soil nitrogen mineralization rate of the Paddy soil and the Yellow brown soil from Nanzhang was higher than other soils.The soil ammonium nitrogen content changed gently from 14 DAI to 28 DAI.The soil ammonium nitrogen declined remarkably after 28 DAI, and the soil nitrogen mineralization rate was below zero during this period, represented as immobilization of soil nitrogen.The soil ammonium nitrogen content decreased in the order: Paddy soil ＞ Yellow brown soil from Nanzhang ＞ Yellow soil ＞ Yellow brown soil from Licuan ＞ Red soil, Cinnamon soil during the soil nitrogen mineralization period.The Paddy soil remained the highest, while the Red and Cinnamon soil remained the lowest soil ammonium nitrogen content among the six soils during the incubation.This demonstrated that the Paddy soil had higher nitrogen-supply ability, but the Red and Cinnamon soil's was lower.Regression analysis showed that the accumulative nitrogen mineralization amount of 7, 14, 21 and 28 DAI had significant or very significant correlation with soil organic matter and total nitrogen content, which meant that the soil organic matter and total nitrogen content were available index for evaluating soil nitrogen-supply ability.
展开▼
