Effects of Water and Nitrogen Utilized by Means of Dripping on Growth of Root and Canopy and Matter Distribution in Spring Wheat

摘要

In order to provide scientific strategies of water and nitrogen regulation, the effects of different amount of watering and nitrogen rate by means of drip irrigation on root/shoot growth and matter distribution in wheat were studied by using methods of soil drill sampling and growth analysis. The results indicated that reducing drip irrigation amounts and nitrogen rate would cause root weight decreased, shoot growth reduced and yield dropped. In water deficit irrigation treatments (2400 m~3/ha), root length and root surface area increased in flowering stage, but rapid declined in milking stage, that severely hampered leaf growth and grain grouting. In milking stage, appropriate irrigation amount (3600 m~3/ha) could maintain higher root weight, root length and root diameter that promoted root/shoot coordinated growing. Nitrogen deficiency significantly reduced dry matter accumulation amount of stem in flowering stage and root length and root surface area in milking stage, that was not conductive to the extension and fulfilling of roots functions and leaded to canopy severely premature aging. High nitrogen supply (urea 450 kg/ha) would cause vigorously growing of shoot and declining of the growth quality of spike and decreasing of the economic coefficient. Water and nitrogen had significant collaborative compensation effects on root/shoot growth and yield traits and the effects of regulating water by nitrogen supply on root traits was larger than on shoot, while regulating nitrogen by water supply on shoot traits was larger than on root, so in actual production, it was necessary to maintain a high level of nitrogen supply in flowering stage but a appropriate level of water supply in milking stage. The drip irrigation amounts and nitrogen rate and yield components indicators in high-yielding drip irrigation wheat field were put forward by analyzing quadratic polynomial equation built by the data of water and nitrogen two factors field experiments.