氮添加对科尔沁人工草地羊草碳氮磷化学计量和土壤特性的影响

Effects of nitrogen addition on stoichiometric ratio and soil characteristics of Leymus chinensis in Horqin artificial grassland

摘要:

【目的】探究科尔沁沙地羊草（Leymus chinensis）碳氮磷化学计量特征和土壤中酶活性及土壤化学性质对氮素添加的响应。【方法】以科尔沁沙地人工建植的羊草为研究对象，对不同施氮水平下 （施肥量分别为 0、50、100、150、200 kg/hm² ）羊草的化学计量特征和土壤特性进行研究。【结果】随施氮水平的提高，羊草有机碳、全氮含量呈增加趋势，全磷含量呈降低趋势；氮肥添加可有效增加土壤中有机碳、全氮含量，降低土壤电导率和 pH 值，并提高土壤中脲酶、磷酸酶、过氧化氢酶的活性；在 150 kg/ hm² 施氮水平下土壤酶活性达到最高，分别为 17. 78 mg/g、60. 21 mg/g、0. 62 mg/g。【结论】追施氮肥可提高土壤中酶的活性，从而促进土壤中营养元素的转化，有利于羊草对土壤中养分和元素的吸收利用， 综合分析得出科尔沁沙地羊草草地推荐施氮量为 200 kg/hm² 。

Abstract:

【Objective】 To investigate the stoichiometric characteristics of Leymus chinensis in Horqin and the response of soil enzyme activity and soil chemical properties to nitrogen addition.【Method】 The stoichiometric characteristics and soil characteristics of L. chinensis artificially planted in Horqin Sandy land were studied under different nitrogen application levels，0 kg/hm² ，50 kg/hm² ，100 kg/hm² ，150 kg/hm² and 200 kg/hm² ，respectively.【Result】 With the increase of nitrogen application，the contents of organic carbon and total nitrogen increased，while the contents of total phosphorus decreased. The addition of nitrogen fertilizer effectively increased the content of organic carbon and total nitrogen in soil，reduced the soil conductivity and pH. The activities of urease， phosphatase and catalase in soil were improved with the highest soil enzyme activity achieved at 150 kg/hm² nitrogen application level，which were 17. 78 mg/g，60. 21 mg/g and 0. 62 mg/g，respectively.【Conclusion】 The application of nitrogen fertilizer can improve the enzyme activities in the soil， thus promotes the transformation of nutrient elements in the soil， and is conducive to the absorption and utilization of nutrients and elements in the soil of L. chinensis. Comprehensive analysis suggested that the recommended nitrogen application amount of L. chinensis grassland in Horqin Sandy Land is 200 kg/hm² .