Chengpeng Lu

Effects of Dicyandiamide on the Accumulation and Leaching Risk of Soil NO3--N in Aquic Brown Soils

A field experiment was conducted at the vegetable production base of Lixiang town in Shenyang city, Liaoning province to study the effects of dicyandiamide (DCD) application on the accumulation and leaching risk of soil nitrate. The results showed that applying DCD significantly decreased the amount of soil NO3--N in the 0-10cm and 10-20cm soil layers compared to without DCD addition (P < 0.01). However, the difference was not significant in the 20-40cm (P > 0.05). These results indicated that the application of DCD reduced the leaching risk of soil nitrate from topsoil to subsoil. At the 28d of fertilizer application, the amount of soil NO3--N was higher in the NP+M, NP+M+2%DCD and NP+M+5%DCD treatments than in the M, M+2%DCD and M+5%DCD treatments, suggesting that the combined application of chemical fertilizer and organic manure weakened inhibiting effect of DCD on the amount of soil NO3--N.

County Sustainable Development and Management in Gansu Loess Plateau Based on Emergy Analysis--Taking Zhengning County in Gansu Province as an Example

Zhengning County in Gansu Province, the cradle of traditional farming culture, is abundant in coal resource and solar energy, but it is ecologically fragile and has significant ecological service function, therefore facing the dual pressure of resource exploitation and environmental protection. Based on the analysis of main emergy indices of Zhengning eco-economic system during the past 20 years, this paper evaluates the efficiency of material metabolism and the capability for sustainable development, and puts forward sustainable management to promote the rapid and harmonious development of west Chinas counties.