长期施肥对双季稻区红壤性水稻土质量的影响及其评价

为量化27年连续施用化肥及其与猪粪、稻草配施处理对双季稻区土壤质量的影响，选择土壤容重、最大持水量、孔隙度、标准化平均质量直径、pH、阳离子交换量、有效养分、土壤有机质、微生物生物量碳、土壤酶和作物生产力等项目作为评价指标，并根据不同指标所具有的功能归纳为：抗物理退化的能力、养分供应和贮藏的能力、抗生物化学退化的能力、保持作物生产力的能力4项功能，以这4项功能为基础划分土壤质量指数(SQI).结果表明：SQI等级范围为0.544（CK）～0.729（施氮磷钾肥＋稻草处理）.与施氮磷钾肥（NPK）处理土壤相比，长期非均衡施肥的PK、NP、NK处理土壤质量发生了退化.土壤缺磷和缺钾是限制水稻生产力的主要因素，即使每年施用30 t·hm^-2猪粪或4.2 t·hm^-2稻草也不能达到满足高产水稻所需要的土壤磷、钾含量水平.长期施用石灰对红壤水稻土质量的提升效果不明显.在南方红壤水稻种植区，氮、磷、钾与有机肥配施是提升土壤质量的最佳措施.

Effects of long-term fertilization on reddish paddy soil quality and its evaluation in a typical double-rice cropping region of China

In order to quantify the effects of 27 years application of chemical fertilizers, pig manure, and rice straw on the reddish paddy soil quality in double rice cropping region, the indices of soil bulk density, porosity, maximum water holding capacity, normalized mean weight diameter, pH, cation exchange capacity, available nutrients, organic matter, microbial biomass C, enzyme activities, and rice yield were selected as the evaluation indicators, and classified into four functional groups, i.e., resistance to physical degradation, plant nutrients supply and storage, resistance to biochemical degradation, and sustaining of crop productivity. The soil quality index (SQI) was calculated based on the four functional groups. The results showed that the SQI ranged from 0.544 in treatment CK to 0.729 in treatment NPK plus rice straw. Treatments PK, NP, and NK induced soil degradation, compared to treatment NPK. The deficiencies of soil P and K were the main limiting factors for the doublerice productivity in reddish paddy soil area. Even though 30 t·hm^-2·a^-1of pigmanure and 4.2 t·hm^-2·a^-1 of rice straw were applied, the soil P and K were still not adequate for the requirement of rice growth. There was no obvious effect of long-term application of lime on the reddish paddy soil quality. The combined application of NPK with organic manure was an important and effective measure in improving soil quality in double rice cropping regions of Southern China.