贵阳市4种森林类型土壤氮矿化的研究

Study of soil nitrogen mineralization in different forests in Guiyang city

2011年11月,采用树脂芯原位测定法,对贵阳市4种不同森林类型(马尾松林、杨树林、樟树林、刺槐和梓木林)土壤氮矿化进行了研究,系统分析了不同森林类型土壤氮素矿化水平。结果表明:4种森林类型土壤铵态氮和硝态氮含量均随管筒培养时间延长而递增,硝态氮含量大于铵态氮含量;几种森林类型管筒内土壤铵态氮和硝态氮含量增加量、氮素矿化量差异较大,大小排序均为樟树林>马尾松林>杨树林>刺槐和梓木林;铵态氮和硝态氮增加量分别为11.65、8.79、7.18、6.33 mg.kg-1,29.29、21.27、19.55、12.86 mg.kg-1;不同林型树脂吸附中硝态氮含量差别较大,造成平均氮净矿化量差异较大,顺序是刺槐和梓木林>杨树林>马尾松林>樟树林,分别为71.47、37.42、35.02、26.75 mg.kg-1,平均氮净矿化速率分别是2.38、1.33、1.24、0.89 mg.kg-1d-1。

Soft nitrogen mineralization of four forest types （Pinus massoniana, Poplar, Cinnamomum camphora, Robinia hispida and Catalpa kaempferi were evaluated by using resin core in situ testing in Dec. 2011, and the mineralization levels under field conditions were determined. The results show that the content ofNH4＋- N was much higher than that of NO3-N, and both of them prolonged with the increase of tube culture time. The increments of NO3- - N, NHa^-N and the quantity of nitrogen mineralization and the nitrogen mineralization ratio for different forest soils tubes had obvious differences, they ordered from big to small as follows： Camphor, Masson pine, Poplar, Robinia and Manchurian. The increments of NH4＋-N were 11.65, 8.79, 7.18, 6.33 mg＇kg-t in four forest types, and that of NO3- -N were 46.0, 29.29, 21.27, 19.55, 12.86 mg·kg^-1. The NO3 -N contents of four forest types with resin adsorption had bigger differences that led bigger differences of average net nitrogen mineralization, they ranked by magnitude as foloows： Robinia and Manchurian Catalpa, Poplar, Masson pine, Camphor, and the mean net nitrogen mineralization rate for four forest types were 2.38,1.33,1.24,0.89 mg·kg^-1 ffl respectively.