%0 Journal Article %T Effects of Fertilizer Placement and Nitrogen Forms on Soil Nitrogen Diffusion and Migration of Red-Yellow Soil in China %A Chaoqiang Jiang %A Huoyan Wang %A Dianjun Lu %A Jianmin Zhou %A Decheng Li %A Chaolong Zu %J Agricultural Sciences %P 1227-1238 %@ 2156-8561 %D 2017 %I Scientific Research Publishing %R 10.4236/as.2017.811088 %X A better understanding of nitrogen (N) diffusion and transformation in soils could reveal the capacity of the biological inorganic N and improve the efficiency of N fertilizers. A field micro-plot experiment was carried out to study the effects of fertilization methods (mixed uniformly with 12 cm top soil, placed in holes at a 12-cm depth, or placed in furrows at a 12-cm depth) and forms of N fertilizers (urea and ammonium phosphate) on the dynamics of soil N¡¯s vertical diffusion and horizontal migration in red-yellow soil. The soil inorganic N ( NH4+-N and NH3--N) content following point deep placement was greater than that from mixed or furrow applications. Under point placement, the migration of soil inorganic N in urea and ammonium phosphate treatments occurred in the 6 - 15 cm layer at a horizontal distance of 0 - 9 cm. However, the nutrient preservation capability of the soil receiving ammonium phosphate was greater than that receiving urea under point deep placement. Thus, point deep placement had a tendency to increase the inorganic N in the soil and reduce inorganic N loss, which probably occurred due to the reduced soil volume with which the N fertilizer was mixed. According to crop growth and fertilizer requirements, the optimized fertilizer placement and N species resulted in a continuously high nutrient supply to crops for 90 d. However, the effects of point deep placement on increasing the N-use efficiency and reducing N loss have to be evaluated under natural field conditions. %K Fertilization Method %K Nitrogen Fertilizer %K Point Deep Placement %K Migration %K Transformation %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=80201