摘要
研究了北方农牧交错带开垦天然草地和退耕地种植紫花苜蓿对土壤磷素有效性的影响。结果表明:试验区土壤速效磷含量整体偏低,均在4 mg/kg以下,C/P比超过4000。草原开垦后,土壤全磷含量显著降低,速效磷含量无显著变化,无机磷占全磷的比例提高。退耕地种植紫花苜蓿4 a后,除典型草原试验区10-20 cm土层全磷含量显著下降外,其余土壤全磷含量无显著变化,无机磷占全磷的比例降低。试验区土壤速效磷含量与碱性磷酸酶活性呈极显著正相关关系,与土壤Ca2-P和Ca8-P含量无显著相关关系,表明速效磷含量主要来源于有机磷的矿化作用。
In order to provide scientific theory in managing and utilizing steppes in agro-pastoral transitional zone, experiments were carried out to determine the contents of available phosphorus, total phosphorus,in organic phosphorus fractions and total organic carbon, soil pH value and the activities of acid and alkaline phosphatase in steppe, cultivated land and alfalfa land in two types of steppes （meadow steppe and typical steppe）. The results showed that the contents of available phosphorus in sampling areas were lower than 4 mg/kg, the ratio between the contents of total organic carbon and available phosphorus was over 4 000. After steppe cultivation, the content Of total phosphorus was significantly decreased, while the content of available phosphorus changed a little. The proportion of inorganic phosphorus in total phosphorus was increased after cultivation. After four years ＇ returning the cultivated land into alfalfa land, the content of soil total phosphorus had no significant change except for a significant decrease in soils at 10--20 cm soil layer in typical steppe. The proportion of inorganic phosphorus in total phosphorus of alfalfa land was significantly higher than that of cultivated land. There existed no significant correlation between the content of available phosphorus and the content of Ca2--P or Ca8--P, while significant correlation was detected between the content of available phosphorus and the activity of alkaline phosphatase, indicating that the available phosphorus was mainly originated from the mineralization of organic phosphorus in soil.
出处
《水土保持学报》
CSCD
北大核心
2009年第1期88-92,共5页
Journal of Soil and Water Conservation
基金
国家"十一五"专项(2006BAD16B01)
关键词
天然草地
紫花苜蓿
速效磷
无机磷组分
steppe
Medicago sativa
available phosphorus
inorganic phosphorus fractions
