长期定量施肥对土壤有机碳储量和土壤呼吸影响

利用1989年在河南省封丘县潮土上建立的用于研究有机肥（用小麦秸秆和饼肥沤制）和化学肥料对土壤有机碳和土壤生产力影响的长期定位试验，于2002年6月至2003年6月在玉米—小麦轮作期内对土壤呼吸进行了研究。试验包括化肥氮磷钾（NKP）、氮磷（NP）、氮钾（NK）、磷钾（PK）、有机肥（OM）、一半化学氮肥和一半有机氮（1/2OM）以及不施肥（CK）7个处理。试验结果表明：以有机肥或以化肥形式配合施用NPK不但可以极大提高土壤生产力，而且有益于增加土壤有机碳储量。有机肥对土壤有机碳含量的提高作用显著高于化肥。玉米生长期的土壤呼吸占全年呼吸量的56%～59%，小麦生长期只占32%～37%。土壤有机碳储量和土壤呼吸量与有机物质的投入有关。综合考虑经济效益（籽粒产量）和环境效益（全球变化），最佳的肥料配比是有机肥料和无机肥料配合施用，寻求合理可行的有机肥和化肥配合比率是实现农业土壤生产功能和环境功能协调统一的关键。

STORAGE OF SOIL ORGANIC C AND SOIL RESPIRATION AS EFFECTED BY LONG-TERM QUANTITATIVE FERTILIZATION

To understand the influence of organic manures composted with the wheat straws, oilcakes and cottonseed cakes, and chemical fertilizers on soil organic carbon and soil productivity, a long-term plot experiment was established in a calcareous fluvo-aquic soil (aquic inceptisol) in Fengqiu county, Henan province, China in September 1989 and was used to monitor soil respiration during the maize and wheat growth seasons from June 2002 to June 2003. The study involved 7 treatments: organic manure (OM), half organic manure plus half fertilizer N ((1/2OM),) fertilizer NPK (NPK), fertilizer NP (NP), fertilizer NK (NK), fertilizer PK (PK) and control (CK). The input of NPK as either organic manures or chemical fertilizers not only greatly improved soil productivity but also was of benefit to the soil as a carbon sink. However, the organic carbon in soils amended with organic manure was greatly higher than in the soil fertilized with chemical fertilizers and increased with the rate of organic manure applied. CO_(2) flux resulted from soil respiration mainly occurred during the maize growth period, accounting for 56%~59% of annual CO_(2) emission, whereas 32%~37% during the wheat growth period. The study suggests that the combination application of organic manures and chemical fertilizers should be the optimal measure from the viewpoint of environment and economy. A further study is necessary to elucidate the reasonable and feasible ratio of organic manure to chemical fertilizers, which will benefit the soil fertility, productivity and global environment.