沙地不同树种人工林土壤氮素矿化过程及其有效性  

Comparative nitrogen mineralization and its availability in certain woody plantations in Keerqin Sand Lands, China

作　　者：陈伏生[1] 曾德慧[1] 范志平[1] 陈广生[1] Singh A.N. 

机构地区：[1]中国科学院沈阳应用生态研究所大青沟沙地生态实验站

出　　处：《生态学报》2006年第2期341-348,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30471377);中国科学院知识创新工程重要方向资助项目(KZCX3SW418);中国科学院沈阳应用生态研究所领域前沿资助项目(SLYQY0409)~~

摘　　要：土壤氮素(N)转化是生态系统重要的生态过程之一,可作为生态恢复评价的重要指标。以位于科尔沁沙地东南缘的章古台地区草地、30年生的樟子松(Pinussylvestrisvar.mongolica)、赤松(P.densiflora)和杨树(Populussimonii)人工林为对象,采用PVC顶盖埋管法和离子交换树脂袋法研究了土壤N矿化特征及其有效性。结果表明,生长季内土壤N净矿化量表现为草地(8.06μgg)和赤松林(9.06μgg)低于樟子松林(18.36μgg)和杨树林(17.88μgg)(p<0.05);树脂吸附的无机N表现为草地(283.50μggdryresin)和杨树林(297.00μggdryresin)最低,樟子松林(440.10μggdryresin)居中,而赤松林(835.65μggdryresin)最高(p<0.05)。综合分析林地土壤理化特性、矿化特征和N有效性,表明樟子松、赤松和小叶杨均可作为固沙造林选择树种,其表现为赤松>樟子松>小叶杨。认为深入开展生态系统N平衡研究有利于更好地评价固沙林的功能。The sand-fixation plantations played an important role in cutting down desertification process in northern China. Soil nitrogen mineralization, which is a key ecological process in poor sandy ecosystems, can be used as a basic index to assess ecosystem function of tree plantations. In this study, soil nitrogen mineralization process and its availability were examined by the methods of in situ closed-top PVC tube incubation and ion exchange resin bags under plantations of pine and poplar, and their neighboring grasslands in the southeastern Keerqin region of China. Results indicated that the accumulative net mineralization in growing season （from April 15 to October 15, 2004） in the grassland （8.06μg·g^-1） and Pinus densiflora （9.06 μg·g^-1） plantation was lower than that in both Pinus sylvestris vat. mongolica （ 18.36μg·g^-1） and Populus simonii （ 17.88μg·g^-1） plantations （p 〈 0.05）. The ratios of nitrification rate to net mineralization rate in grassland, P. sylvestris var. mongolica, P. densiflora, and Populus simonii plantations were 0.88, 0.91, 0.82, 0.87, respectively, which indicated that the soil nitrification rate in the study area is more intensive than soil net ammonification processes, and the NO3^--N was the major N form absorbed by plants in the study area, which might due to the higher soil pH values （ 〉 6.6） and strong human disturbances in the study area. The percentages of net mineralization amount to soil total N contents in grassland, P. sylvestris var. mongolica, P densiflora, and Populus simonii plantations were 2.49%, 4.42%, 2.77%, 4.26%, respectively, implying that N turnover rates in grassland and P. densiflora plantation were very low, while those in P. sylvestris var. mongolica and Populus simonii were relatively higher. The accumulative mineral N absorbed by resin from May 15 to October 1 in both the grassland （283.50 μg·g^-1 dry resin） and Populus simonii plantations （297.00μg·g^-1 dry resin） was the lowest, while that in P. sylvestr

关 键 词：固沙林 土壤氮素 矿化过程 顶盖埋管法 离子交换树脂袋法 科尔沁沙地 

分 类 号：S714[农业科学—林学]