论文部分内容阅读
以黄土丘陵区子午岭林区裸露地为对照,选择撂荒地、白羊草草地、油松、山杨和辽东栎林地五种典型植被群落下0—10cm和10—20 cm土层的土壤为研究对象,对土壤无机氮、有机氮、微生物量氮含量和脲酶、蛋白酶以及硝酸还原酶的活性进行了研究。结果表明,土壤中各种氮素基本表现为乔木林,尤其是辽东栎和油松下含量最高,而有机氮则在白羊草地富集明显。铵态氮为子午岭林区速效氮的主要形式。土壤铵态氮与微生物氮极显著正相关;有机氮和亚硝态氮、矿化氮、微生物氮均显著正相关。脲酶和硝酸还原酶活性在辽东栎群落下最高,蛋白酶在白羊草地下较高,且脲酶活性在土壤上层高于下层,而蛋白酶和硝酸还原酶并没有表现出明显规律。脲酶活性和铵态氮、有机氮含量显著正相关,与微生物量氮极显著正相关;硝酸还原酶活性与铵态氮含量显著正相关;蛋白酶活性和土壤各种氮素含量无相关性。
Taking the bare land in Ziwuling area of Loess Hilly Region as control, the soil types of 0-10 cm and 10-20 cm soil layers in five typical vegetation communities of abandoned land, white sheep grassland, Pinus tabulaeformis, Populus davidiana and Quercus liaotungensis were selected as The subjects studied the activities of soil inorganic nitrogen, organic nitrogen, microbial biomass nitrogen and urease, protease and nitrate reductase. The results showed that all kinds of nitrogen in the soil showed arbor forest, especially in Quercus liaotungensis and Pinus tabulaeformis, while the contents of organic nitrogen in Arborvitae grassland were the highest. Ammonium nitrogen is the main form of available nitrogen in Ziwuling area. There was a significant positive correlation between soil ammonium nitrogen and microbial nitrogen. Organic nitrogen was positively correlated with nitrite nitrogen, mineralized nitrogen and microbial nitrogen. The activities of urease and nitrate reductase were highest in Quercus liaotungensis and the protease was higher in the ground of A. chinensis, and the urease activity was higher in the upper layer than in the lower layer. However, protease and nitrate reductase did not show obvious rules. Urease activity was significantly and positively correlated with ammonium nitrogen and organic nitrogen, and positively correlated with microbial biomass nitrogen. Nitrate reductase activity was positively correlated with ammonium nitrogen content. There was no correlation between protease activity and soil nitrogen content.