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在年降水丘４５０～５１０ｍｍ的半湿润易旱地区的壤质红垆土上，以春玉米为供试作物进行了大田试验。玉米生长期间，每隔１０天分别测定不同栽培和施氮量处理的蒸腾强度，叶面积，伤流量，伤流液成分，叶水势，叶片糖分含量，并刈割玉米地上部分，测定生长量，分层采取２ｍ土层的土壤，测定含水量，以研究施用Ｎ肥对提高旱地作物利用土壤水分的作用机理和效果。试验表明，施用氮肥促进了作物根系发育，扩大了作物觅取水分和养分的土壤空间，增大了蒸腾强度和伤流量，降低了叶水势，提高了伤流液中氨基酸含量，使根系活性增强，作物吸取和运转土壤水分的能力提高。利用直接测定的结果计算，施肥不仅提高了作物蒸腾量，减少了土壤水分蒸发量，增高了Ｔ／ＥＴ比值，而且提高了蒸腾效率，增加了叶片的糖分含量，使蒸腾的水分得到了更有效地利用。施氮区与无氮区相比，消耗的土壤水分无明显区别，但由于施肥区显著增产，水分的利用效率明显提高。用蒸散量计算出来的水分利用效率，ＷＵＥ（ＥＴ），随施氮量增高而增高；用蒸腾量计算出来的水分利用效率，ＷＵＥ（Ｔ），因产物而不同：籽粒的水分利用效率与施氮量成直线关系，而干物质的水分利用率不因施氮量而变化，表明施肥对提高经济产物的水分利用效率更?
Field experiments were conducted on spring red maize as a test crop on loamy soil in semi-humid and drought-prone areas with an annual precipitation of 450-510 mm. During the growth of corn, the transpiration intensity, leaf area, traumatic flux, wound fluid composition, leaf water potential and leaf sugar content under different cultivation and nitrogen application rates were measured every 10 days. The aboveground parts of corn were mowed and the growth, The soil of 2m soil layer was stratified and the water content was measured to study the action mechanism and effect of applying N fertilizer on improving soil moisture utilization of dry land crop. The results showed that the application of nitrogen fertilizer promoted root development of crops and expanded soil space for crops to seek water and nutrients, increased transpiration intensity and traumatic flow, reduced leaf water potential, increased amino acid content in wound fluid, enhanced root activity, The ability of crops to extract and operate soil moisture has increased. Using the direct measurement results, fertilization not only increased crop transpiration, reduced soil water evaporation, increased T / ET ratio, but also increased transpiration efficiency, increased leaf sugar content, and transpirationed water was more effective Use. Compared with nitrogen-free zone, there was no obvious difference in soil water consumption between nitrogen-applied zone and nitrogen-free zone. However, due to the significant increase in fertilization zone, water use efficiency was significantly increased. The water use efficiency calculated by evapotranspiration, WUE (ET), increased with the increase of nitrogen application rate. The water use efficiency, WUE (T), calculated from the transpiration value varied with the product: the water use efficiency Nitrogen content in a linear relationship, and the dry matter of water use efficiency does not vary due to nitrogen rates, indicating that the use of fertilizers to improve economic efficiency of the water use more?