关键词: 双氰胺, 纳米碳, 尿素, 碳酸氢铵, 油菜, 氮肥利用率

Abstract: By using geostatistics and based on timelag classification standard, a comparative study was made on the land surface dead combustible fuels in Huzhong forest area in Great Xing’an Mountains. The results indicated that the first level land surface dead combustible fuel, i.e., 1 h timelag dead fuel, presented stronger spatial auto-correlation, with an average of 762.35 g·m^-2 and contributing to 55.54% of the total load. Its determining factors were species composition and stand age. The second and third levels land surface dead combustible fuel, i.e., 10 h and 100 h time-lag dead fuels, had a sum of 610.26 g·m^-2, and presented weaker spatial auto-correlation than 1 h timelag dead fuel. Their determining factor was the disturbance history of forest stand. The complexity and heterogeneity of the factors determining the quality and quantity of forest land surface dead combustible fuels were the main reasons for the relatively inaccurate interpolation. However, the utilization of field survey data coupled with geo-statistics could easily and accurately interpolate the spatial pattern of forest land surface dead combustible fuel loads, and indirectly provide a practical basis for forest management.

Key words: dicyandiamide, nano-carbon, urea, ammonium bicarbonate, pakchoi, fertilizer N use efficiency.