关键词: 控释氮肥, 氨挥发, 脲酶活性, pH值, 溶出率

Abstract: The emergy analysis of the agroecosystems in Jinlin Province indicated that in 1990-2007, there was an increasing trend in the total emergy input, among which, economic system feedback emergy accounted for more than 85%, and the ratio of renewable emergy input to the total emergy was above 80% (labor force em
ergy input accounted for about 60%). There was also an increasing trend in the total output emergy, being from 5.50×10²² sej in 1990 to 13.61×10²² sej in 2007, with an increment of 147%. The output emergy was mainly from planting and pasturage. In the past 17 years, the net emergy output ratio was relatively high, environment load ratio was relatively low, sustainable development emergy index maintained at a higher level and showed an increasing trend (from 2.64 in 1990 to4.98 in 2007), but the industrial assistant emergy input in the social economic feedback emergy of the agroecosystems was in shortage. On the whole, there was agreater potential in the agricultural sustainable development of Jilin Province
.

Key words: Controlled-release N fertilizer, Ammonia volatilization, Urease activity, pH value, Leaching rate