北方冬小麦/夏玉米轮作体系土壤氨挥发的原位测定

采用通气法测定了北方冬小麦／夏玉米轮作体系田间土壤的原位氨挥发。结果表明，与冬小麦施用基肥相比，夏玉米追肥后土壤的氨挥发速率很快升高，但军发高峰期持续时间较短，最大氨挥发速率亦低于冬小麦，冬小麦拨节期追肥，氨挥发速率低且呈波动变化，未出现高峰值，从整个生长季节来看，冬小麦不施氮和每公顷施氮120、240、360kg时的累计挥发量分别为4．4、6．9、13．0、38．4kgN/hm^2，夏玉米为8．4、15．1、20．0、26．1kgN/hm^2。按我国北方冬小麦／夏玉米播种面积1864．4万hm^2计，每年由氨挥发向大气排放的氨素达23．8－120．2万t，其中17．2－96．4万t来自氮肥，相当于氮肥投入的2．1％－9．5％。

In Situ Determination of Ammonia Volatilization from Wheat Maize Rotation System Field in North China

Ammonia volatilization from soil is an important pathway for fertilizer N loss from field, and also a major source for air and environment pollution. Majority of soils in north China are calcareous ones with higher pH that has created a condition favorable for such loss, and intensive cropping with over application of N fertilizer and unreasonable fertilization practices has made the situation more serious. Winter wheat ( Triticusp aestvum L.) and summer maize ( Zea Mays L.) are major crops in this ar...