Emergy analysis of planting system at Gongzhuling county in the main grain production region in Northeast China Plain

Based on the emergy theory, this paper quantitatively analyzes the emergy flow of planting system(maize, soybean and rice) in Gongzhuling county in Jilin Province through serial emergy indexes. It figured out the transition rate of solar emergy joules of the three main crops(maize, soybean and rice) in Gongzhuling county, and the results were 1.95×10⁴, 4.98×10⁴, 3.59×10⁴ sej/J, respectively. It evaluated the natural environmental production and society economic development .The results show that the emergy input level of planting system in Gongzhuling county is higher than that in developed countries. The focal point of planting system emergy input is to raise the level of farming technology and increase renewable resource emergy input, especially using agricultural ecological engineering technology and biotechniques, in this way, the agriculture of Gongzhuling county can develop sustainablely.