不同配方施肥对长期缺施钾肥的红壤性水稻土微生物特性的影响

为了验证平衡施肥对长期缺施钾肥的南方红壤性水稻土的修复效果，通过2年盆栽试验，以五种不同施肥处理（NPK、NPKSi、NPKOM、NPhK、NPhKOM），研究了长期缺施钾肥的水稻土的微生物特性，结果发现，在对照（NPK）基础上增施硅肥（NPKSi）、钾肥（NPhK）能促进细菌和放线菌数量的增长，提高微生物活度，加速微生物量N、P的转化，同时也能提高微生物量C。相反，在淹水条件下配施有机肥（NPKOM），由于降低了水稻根际环境的氧化还原电位，使根际微生物生长萎缩，微生物活度、微生物量C无显著提高；虽然土壤微生物量N、P随之增加，但有机N的矿化减弱，植株可吸收的有效态养分减少。增施钾肥的同时配施有机肥（NPhKOM）具有增施钾肥的优点，即可提高微生物活度、提高微生物量C，加速有机N、P的矿化，但同时也会减少微生物数量。因此在缺钾水稻土的修复实践中，常规施肥的基础上对水稻增施硅肥、钾肥应是有效举措，而配施有机肥则须谨慎:有机肥或须适量酌施，或须结合增施钾（硅）肥。

Effects of different fertilizations on soil microbial characteristies in a paddy soil from red earth with long-term K-deficiency

To test remediation effects of balanced fertilization on a paddy soil with loog-term K-deficiency,a pot experi- ment has been being carried out since April,2005 with five fertilization treatments(NPK,NPKSi,NPKOM,NPhK and NPhKOM).The results showed that the amount of bacterium and actinomyces,microbial biomass C and the microbial activities increased,and the rate of mineralization of organic nitrogen and phosphorus promoted with the increasing appli- cation rate of silicon fertilizer(NPKSi)or potassium fertilizer(NPhK).While the above mentioned parameter appeared an opposite trend with the addition of organic manure(NPKOM)because it resulted in a worse anaerobic condition though the microbial biomass N and P increased.Increasing potassium application companied with organic manure(NPhKOM) increased microbial biomass C and microbial activity,but decreased the amounts of microbe.Consequently,applying sili- con or potassium fertilizer may remediate the paddy soil with long-term K-deficiency more efficiently.Excessive applica- tion of organic manure application should be avoided.Combine application of silicon fertilizer or potassium fertilizer was recommended suppose large amount of organic manure was addressed under our study condition.