Absorption and utilization of different nitrogen forms for sweet potato Suitable nitrogen fertilization mode for high yield and quality and high N use efficiency in high density direct-sown rapeseed(Brassica napus L.) Effect of different N rates on nutrient accumulation and nitrogen use efficiency in rainfed land Lanzhou lily Effects of Wheat Residue Incorporation and Nitrogen Management Techniques on Formation of the Grain Yield of Rice Effects of sulfur-and polymer-coated controlled releaseurea fertilizers on spatial-temporal variations of soil NO-3-N and nitrogen balance and nitrogen use efficiency Dyanmics and residue of soil nitrate in summer maize field of North China Effects of fertilizer-N application for double early rice on the yield,nitrogen use efficiency and soil nitrogen content of double late rice Effect of different furrow irrigation patterns on cotton nitrogen absorption and nitrogen fertilizer use