【作者】 顾明华； 区惠平； 刘昔辉； 黄景； 黎晓峰； 李柳霞； 沈方科； 江立庚；

【Author】 Gu Minghua Ou Huiping Liu Xihui Huang Jing Li Xiaofeng Li Liuxia Shen Fangke (Guangxi University,Nanning 530005,China)

【机构】 广西大学农学院；

【摘要】 在水稻不同生育期.根据土壤剖面分层结构采集稻草免耕稻田的土壤样品.研究不同耕作方式、不同土层稻田土壤的氮素形态及氮素生理群特征。结果表明:①在 N 素生理群方面,免耕提高了0～5 cm 土层氨化细菌的数量,这种趋势在稻草免耕上表现更明显;0～5 cm 和5～12 cm 土层亚硝化细菌数量常耕明显高于免耕,12～20 cm 土层则相反,稻草免耕较稻草常耕降低了0～20 cm 土层的亚硝化细菌和反硝化细菌数量;在水稻拔节期和成熟期,免耕提高了0～5 cm 层嫌气性固氮菌数量;②在 N 素形态方面,碱解 N 和全氮免耕较集中分布0～5 cm 土层。明显比常耕高,而5～12 cm 和12～20 cm 土层比常耕低,铵态氮和硝态氮在免耕处理中有一定差异,而稻草免耕可使其在0～5 cm、5～12 cm 和12～20 cm 土层均有所提高;③相关性和多元回归分析表明:与氨化细菌相关最大的是铵态氮,其次是全氮,最后是碱解氮;与亚硝化细菌、反硝化细菌相关最大的是铵态氮含量;与嫌气性固氮菌相关最大的是碱解氮,其次是硝态氮。综合各土层氮素生理群数量与不同形态氮含量,稻草免耕更有利于稻田氰素供应与养分积累。更多还原

【Abstract】 Characteristics of nitrogen forms and nitrogen bacteria groups in paddy soils under no-tillage with straw (NTS)were investigated.Soil samples were collected according to the structure of the paddy soil. The result showed that:i)In the layers of 0～5 cm of soil,the number of Ammonifying bacteria for no-till- age (NT) were increased,the Nitrosobacteria and Denitrifying bacteria were redueed in NT compared to conventional tillage (CT).In the layer of 12～20 cm of soil,it is opposite.The Anaerobic fixed dinitrogen in NT or NTS was increased remarkably in the layer of 0～5 cm of soil under the elongation and ripening. ii)Aikali-hydrolyzable N and Total nitrogen were more concentrated and greater in the layer of 0～5 cm and lower in the layers of 5～12 cm and12～20 cm.from NT than CT.There exists a little difference in Ammo- nium N and Nitrate N amounts for NT,while those in the NTS for three layers were raised,iii)Significant correlation and multiple regression analysis further revealed that Ammonifying bacteria had a first signifi- cant relation with Ammonium N,the secondly with Total N and the last with Aikali-hydrolyzable N.The Nitrosobacteria and Denitrifying bacteria elosely bound up with Ammonium N.The Anaerobic fixed dini- trogen correlated closest with Aikali-hydrolyzable N and next most closely with Total N.The results im- plied that NTS was more propitious to provide N and maintain soil fertility.更多还原