目前在梨树生产上普遍存在大小年现象,影响着梨的丰产稳产。造成这一问题的原因很多,但生产和科研的丰富实践证明,合理留果、疏除过多的花和果,是克服梨树大小年的重要途径之一。人工疏花和疏果是一项相当费工的措施,面积大、劳力缺的果园往往难于按要求及时完成。我们从1974年起,在晋县林业局的大力支持下,开始进行梨树化学疏花疏果试 Pear tree production is currently widespread size phenomenon, affecting the peanut yield and stable. There are many reasons for this problem. However, rich practice in production and scientific research proves that one of the most important ways to overcome the size of pear tree is reasonable rationing and thinning of flowers and fruits. Artificial flower and fruit thinning is a rather laborious measure, large area, lack of labor orchards are often difficult to complete in time required. Since 1974, with the strong support of Jinxian Forestry Bureau, we started to carry out the chemical thinning and fruit thinning test