Effects of Nitrogen on the Dry Matter,Nitrogen Accumulation and Distribution of Cotton under Short-term Soil Drought during the Flowering and Boll-forming Stage Characteristics of Accumulation and Distribution of Nitrogen and Dry Matter in Wheat at Yield Level of Ten Thousand Kilograms per hectare Changes in nitrogen accumulation, distribution, translocation and nitrogen use efficiency in different wheat cultivars under different irrigation conditions Effects of supplemental irrigation based on measured soil moisture on nitrogen accumulation, distribution and grain yield in winter wheat Characteristics of dry matter production and nitrogen use efficiency of 37 spring maize hybrids with high-yielding potential in north of China