Abstract:

To reveal the restoration process of Caragana Korshinskii plantations in loess hilly region, the Caragana Korshinskii plantations with 15a, 30a and 40a were selected as study subjects and the slope cropland was chosen as control. Based on the method of field investigation and laboratory analysis, the soil enzyme activity, soil nutrient change and the relationship between them were studied. The results showed that the activities of soil urease, sucrase, catalase and alkaline phosphatase significantly increased in the Caragana Korshinskii plantations, and the activities of urease and sucrase increased with the increase of the years, which were more sensitive than catalase and alkaline phosphatase that followed the same increasing trend. Compared with the slope cropland, the activity of sucrose in 0~10cm depth increased by 40%, 84%, 109%, respectively, and urease increased by 5.32, 6.11, 8.58 times, respectively. With the increase of soil depth, the enzyme activity decreased. The correlation analysis showed that the activities of urease, sucrase, catalase and alkaline phosphatase had obviously positive correlation with soil dissolved organic carbon and nitrogen, available phosphorus, organic carbon, total nitrogen and total phosphorus (P< 0.05, P<0.01), which could be used as a biological index to evaluate the soil quality of Caragana Korshinskii plantation.

Key words: Loess hilly region, Vegetation restoration, Caragana Korshinskii, Soil enzyme activity, Soil quality

摘要：

为揭示黄土丘陵区柠条人工林地土壤生物活性与肥力恢复过程，选择退耕种植柠条后恢复15 a、30 a、40 a的林地作为研究对象，并以坡耕地（CK）为对照，研究了柠条林地恢复过程中土壤4种酶活性变化特征及其与碳氮磷养分关系。结果表明：坡耕地种植柠条林后土壤脲酶、蔗糖酶、过氧化氢酶和碱性磷酸酶活性均显著增加，而随着柠条年限的增长，脲酶、蔗糖酶活性变化比过氧化氢酶、碱性磷酸酶更敏感，均呈现出递增的趋势，对比耕地，在0～10 cm土层蔗糖酶增幅可达40%，84%，109%，而脲酶增幅可达5.32，6.11，8.58倍，随着土壤深度的增加，酶活性降低。相关性分析表明，脲酶、蔗糖酶、过氧化氢酶和碱性磷酸酶活性与土壤可溶性有机碳氮，速效磷，有机碳，全氮，全磷之间都具有显著或极显著的正相关关系（P<0.05，P<0.01），可以作为评价柠条林土壤质量的生物学指标。

关键词: 黄土丘陵区, 植被恢复, 柠条, 土壤酶活性, 土壤质量