长期施用化肥和秸秆对活性有机质组分的影响

Composition of Soil Organic Matter Affected by Long-Term Application of Chemical Fertilizer and Incorporation of Rice Straws

以长期定位试验为基础,分析了长期施用化肥和秸秆对土壤不同组分C、N的影响。结果表明:连续施肥16年后,与CK处理相比,单施化肥使土壤全N、有机C、轻组有机N、颗粒态有机N、碱解N、易氧化有机C分别增加了13.8%,9.4%,38.2%,20.0%,19.7%和26.3%,但并没有增加轻组有机C量和颗粒态有机C量。化肥与秸秆配施后,土壤全N、有机C和不同组分C、N含量都显著大于单施化肥。单施化肥显著降低了土壤有机质、轻组有机质、颗粒态有机质的C/N比,但化肥与秸秆配施后,其C/N比并没有继续降低。此外,易氧化有机C量与土壤有机C量显著相关,颗粒态有机N量、轻组有机N量、碱解N和土壤全N间也存在显著相关性。

Based on a long-term fertilization experiment carried on from 1989 to 2005, effects of chemical fertilizer and rice straw on C and N in different fractions of soil organic matter in a paddy soil was studied in the experiment. Results showed that 16 consecutive years of application of chemical fertilizers increased total organic carbon （TOC）, total nitrogen （TN）, coarse fraction organic matter （CFOM）-N, light fraction organic matter （LFOM）-N, the easily oxidizable organic carbon （EOC）, and alklyzable （NaOH） organic N （NaOH-N） by 9.4%, 13.8%, 20.0%, 38.2%, 26.3% and 19.7%, respectively over those in CK, but not the organic carbon in LFOM or CFOM, and instead decreased C/N ratio in SOM, LFOM and CFOM. In Treatment NPK ＋ OM （rice straws）, TOC, TN and N and C contents in different organic matter fractions were much higher than in Treatment NPK, and the decreasing trend of C/N ratio stopped. In addition, significant relationship was observed between EOC and TOC, and between LFOM-N, CFOM-N, NaOH-N and TN.