半干旱地区苹果不同时期施用氮肥试验庞占荣，朱世新，孙凤山（辽宁省水土保持研究所１２２０００）有关氮肥施用时期的研究，人们已经做过大量的工作，但对半干旱冷凉地区的果树研究甚少。辽宁西部属于半干旱地区，春季干旱，夏季多雨，无霜期短，果树春季生长弱，夏秋徒... Application of nitrogen fertilizer in different periods of apple in semi-arid area Pang Zhanrong, Zhu Shixin, Sun Fengshan (Liaoning Provincial Institute of Soil and Water Conservation 122000) There has been a lot of work done on the period of nitrogenous fertilizer application, but there is little research on the fruit trees in semi-arid and cool area . Western Liaoning belongs to the semi-arid area, with spring drought, rainy summer, short frost-free period, weak growth of fruit trees in spring and summer fall ...