A preliminary study on the regulated deficit irrigation system of winter wheat THE ADJUSTMENT OF SOIL WATER AND NITROGEN PHOSPHORUS NUTRITION ON ROOT SYSTEM GROWTH OF WHEAT AND WATER USE Responses of winter wheat tillers at different positions to low temperature stress at stem elongation stage and their freezing resistance evaluation. Effects of nighttime warming on winter wheat root growth and soil nutrient availability. SIMULATION ON FUNCTIONAL EQUILIBRIUM OF WINTER WHEAT ROOT AND SHOOT UNDER DIFFERENT SOIL WATER REGIMES