滴灌棉田有机碳组分对不同比率有机无机肥配施的响应

Response of Soil Organic Carbon Fraction to Different Ratios of Organic /Inorganic Fertilizer Application in Cotton Field

[目的]研究有机无机肥配施对土壤有机碳的影响,寻求合理的有机无机配施的施肥策略.[方法]在滴灌条件下,通过设置CK（不施肥）、100％ NPK （N 300 kg/hm^2;P2O5 90 kg/hm^2;K2O 60 kg/hm^2）、80％ NPK＋OF1（80％ NPK＋有机肥3 000 kg/hm^2）和60％ NPK＋ OF2（60％ NPK＋有机肥6 000 kghm^2）四个处理,进行连续3年棉田定位试验,研究土壤总有机碳、活性有机碳、土壤碳库管理指数及微生物量碳等土壤碳库特征值对不同比率有机无机肥配施的响应.[结果]施用3 000 ～6 000 kg/hm^2有机肥,替代20％ ～ 40％化肥可显著（P＜0.05）提高土壤总有机碳与活性有机碳含量.在第3年,80％ NPK＋ OF1和60％ NPK＋ OF2处理土壤有机碳分别比100％ NPK处理增加了1.31和1.76 g/kg,增幅为11.4％和15.3％,而土壤活性有机碳则分别比100％ NPK处理增加了0.59和0.79 g/kg,增幅分别为22.6％和53.0％,且处理间差异均达到显著水平（P＜0.05）.与100％ NPK相比,施用3 000～6 000 kg/hm^2有机肥可使土壤CPMI值增加28.2％～69.7％,并可显著增加微生物量碳（P＜0.05）.[结论]施用3 000～6 000 kg/hm^2的有机肥,替代20％～ 40％化肥可明显增加土壤总有机碳和活性有机碳,且活性有机碳比总有机碳更敏感,有机肥替代部分化肥的施肥策略对增加滴灌棉田土壤碳库质量、提高土壤肥力有明显效果.

[Objective] This paper studied the effect of different ratios of organic/inorganic fertilizer application,and the reasonable fertilization strategy of organic combined with inorganic fertilizers was researched.[Method] In the present reseach,a three-year plot experiment which included CK （no fertilizer）,100% NPK （inorganic N,P,K fertilizer）,80% NPK ＋ OF1 （80% NPK fertilizer combined with 3 000 kg/hm^2 compost fertilizer）,60% NPK ＋ OF2 （60% NPK fertilizer combined with 6 000 kg/hm^2 compost fertilizer） was conducted.Actually the four treatments were established to study the response of soil organic carbon characteristic （such as soil organic carbon,labile organic carbon,soil carbon pool management index and soil microbial biomass） to different ratios of organic/inorganic fertilizer application.[Result] Application of 3 000-6 000 kg/hm^2 organic fertilizer substitute for 20%-40% inorganic fertilizer significantly （P 〈 0.05） increased soil organic carbon and labile organic carbon content.Compared with 100% NPK treatment,soil organic carbon was increased by 1.31 g/kg and 1.76 g/kg （P 〈0.05）,respectively,and its increment degree of 11.4% and 15.3% was obtained with both 60% NPK ＋ OF2 and 80% NPK ＋ OF1 treatments at the third year （2013）.Similarly,60% NPK ＋ OF2 and 80% NPK ＋ OF1 significantly （P 〈0.05） increased the soil labile organic carbon by 0.59 g/kg and by 0.79 g/kg,in contrast with 100% NPK treatment,ant its increment degree was 22.6% and 53.0% respectively,and there was a significant （P 〈 0.05） difference between 3 000 -6 000 kg/hm^2 organic fertilizer amendment treatments with 100% NPK.Furthermore,through organic manure application,soil carbon pool management index （CPMI） was enhanced by 28.2%-69.7%,and soil microbial biomass carbon （MBC） was also obviously increased compared with 100% NPK.[Conclusion] In conclusion,3 000-6 000 kg/hm^2 organic fertilizer substitute for 20%-40% inorganic fertilizer had a substantial role on both soil organic carbon and labile organic carbon increment,and labile organic carbon was more sensitive than soil organic carbon,the fertilization strategy of organic fertilizer partial substitution for chemical fertilizer was beneficial for improving soil organic carbon quality and soil fertility in drip irrigation condition.