长期定位施肥对旱作农田土壤全氮及其组分的影响

Effect of Long-term Fertilization on Soil Total Nitrogen and Its Fractions in Dryland Farming System

基于田间定位试验,研究了长期施肥对旱作冬小麦农田土壤全氮及其组分的影响,试验设4个处理(对照不施肥CK、氮磷配施NP、化肥与有机肥配施NPM以及长期休闲地BL),测定了0—15,15—30,0—30cm土壤全氮、微生物量氮、潜在矿化氮和颗粒有机氮含量。结果表明,长期持续施肥30a后,在0—30cm土层,NPM处理土壤全氮、微生物量氮、潜在矿化氮分别较CK提高了35.0%,27.0%和48.9%(P<0.05),且这种增加作用在15—30cm更明显,土壤全氮增幅达到41.3%(P<0.05),但颗粒有机氮差异并不显著;此外,NPM处理微生物量氮、颗粒有机氮含量较NP处理分别提高了35.2%,307.5%(P<0.05),而NP处理与CK仅潜在矿化氮差异显著。与种植作物相比,长期休闲降低了土壤全氮、微生物量氮、潜在矿化氮和颗粒有机氮含量,差异分别为15.0%,1.8%,31.3%和33.6%,但均未达到显著水平。相关性分析表明,土壤全氮、潜在矿化氮、微生物量氮和颗粒有机氮两两之间存在着显著的正相关关系。总的来说,长期持续施入有机肥能够有效地增加旱作农田土壤全氮,同时增加其组分含量,有助于维持土壤健康,保持其供氮能力。

A long-term winter wheat flied experiment was conducted to detect the effect of long-term fertilization on soil total nitrogen and its fractions. 4 treatments were established, including control treatment without fertilization （CK）, nitrogen and phosphorus combined fertilization （NP）, nitrogen, phosphorus and manure combined fertilization （NPM） and bare land without fertilization and crop （BL）, and the contents of soil total nitrogen, microbial biomass nitrogen, potential mineralized nitrogen and particulate organic nitrogen of 0- 15 cm, 15-30 cm and 0-30 cm soil layers were measured. The results showed that the contents of soil total nitrogen, microbial biomass nitrogen and potential mineralized nitrogen at 0-30 cm soil layer increased by 35.0%, 27.0% and 48. 9% （P〈0.05） in NPM, respectively, compared with those in CK after 30-year continuous fertilization. The effect of long term fertilization on soil nitrogen fractions was more significant at 15-30 cm soil layer. The contents of soil total nitrogen at 15-30 cm soil layer increased by 41.3% （P〈0.05） in NPM, compared with those in CK, but no difference was found in particulate organic nitrogen content. In addition, soil microbial biomass nitrogen and particulate organic nitrogen content in NP increased by 35.2% and 307.5% （P-0.05）, respectively, compared with those in CK. The content of potential nitrogen mineralization was the only one which has big difference between NP and CK. No crop growing reduced the contents of soil total nitrogen, microbial biomass nitrogen, potential mineralized nitrogen and particulate organic nitrogen by 15. 0%, 1.8%, 31.3% and 33.6 %, respectively, but the reductions were not significant. Correlation analysis showed that the contents of soil total nitrogen, potential mineralization nitrogen, microbial biomass nitrogen and particulate organic nitrogen showed significant positive correlations with each other. In general, continuous long-term manure addition can effectively increase the contents of soil total nitrogen and its active fractions, and is helpful for maintaining soil health and nitrogen supply capacity.