摘要
通过原位进行低氮(LN,50kgN.hm-.2a-1)、中氮(MN,100kgN.hm-.2a-1)和高氮(HN,150kgN.hm-.2a-1)处理,研究了川南天然常绿阔叶林土壤酶活性特征及其对模拟N沉降的响应。结果表明,森林土壤过氧化氢酶、脲酶、纤维素酶和蔗糖酶的活性在垂直分布上均表现为0～10cm土层高于10～20cm土层;各种土壤酶活性的季节变化明显,但土壤酶活性还因取样时间和土层不同而异。其中,0～10cm和10～20cm土层中过氧化氢酶活性高峰均出现在秋季(92d);0～10cm土层中脲酶活性高峰出现在秋季,而10～20cm土层中脲酶活性高峰出现在冬季(183d);0～10cm和10～20cm土层中土壤纤维素酶活性高峰则出现在翌年春季(274d);0～10cm土层中蔗糖酶活性有两个高峰,分别出现在秋季和翌年春季;而10～20cm土层中蔗糖酶活性只有一个高峰,出现在翌年春季。总体上,常绿阔叶林中不同土壤酶活性对N沉降的响应有所差异。其中,N沉降降低了常绿阔叶林土壤纤维素酶和过氧化氢酶活性,增加了土壤脲酶和蔗糖酶活性。不同浓度N处理间酶活性表现出了不同程度的差异性,但其变化的规律还不明显。
To explore the response of soil enzyme activities to simulated nitrogen deposition, an in situ experiment was conducted in a native evergreen broad-leaved forest in southern Sichuan. Nitrogen-addition was carried out within the forest in 2005. Four nitrogen addition treatments i. e, null nitrogen level （CK）, low nitrogen level （LN, 50 kg N hm^-2 a^-1）, moderate nitrogen level （ MN, 100 kg N hm ^-2 a^-1 ） and high nitrogen level （ HN, 150 kg N hm^-2 a^-1） , were established in the forest. All nitrogen treatments were carried out in triplicates. All plots of treatments were laid out randomly. Beginning in July, 2005, Ammonium nitrate （NH4NO3 ） solution was sprayed by hand monthly onto the floor of these plots throughout the whole year. During the study period, the enzyme activities of hydrogen peroxides, urease, cellulose and invertase presented a virtical higher distribution at 0 - 10 cm depth than those at 10 - 20 cm depth. All enzyme activities changed with seasons, but their patterns varied depending on sampling time and soil layers. The peaks of activities occurred in Autumn at both soil depths of 0 -10 cm and 10 -20 cm for hydrogen peroxides, for urease, which occurred in Autumn at the depth of 0 - 10 cm and in Winter at the depth of 10 - 20 cm, for cellulose at both soil depths, which occurred in Spring, for invertase at the depth of 0- 10 cm, which occurred in Autumn and Spring, and at the depth of 10 -20 cm, which occurred only in Spring. Overall, the responses of soil enzyme activities to nitrogen deposition in the evergreen broadleaved forests were different. Nitrogen deposition had negative effect to some degree on hydrogen peroxides activities. In contrast, the urease activities were found to be stimulated by nitrogen deposition. The results also showed that cellulose activities decreased in all treatments, whereas invertase activities increased to some degree by nitrogen deposition.
出处
《生态学报》
CAS
CSCD
北大核心
2009年第3期1234-1240,共7页
Acta Ecologica Sinica
基金
国家科技部"十五"重大科技攻关资助项目(2004BA606A-06)
四川省科技攻关资助项目(05SG023-009)
关键词
土壤酶活性
常绿阔叶林
氮沉降
川南
soil enzyme activities
evergreen broad-leaved forest
nitrogen deposition
southern Sichuan
