套袋对苹果生产投资结构的影响及密植园遮光问题

Influence of Bagging on the Structure of Apple Production Investment as Well as Its Resultant Problem of Shading

套袋技术目前已经广泛应用于果树生产，特别是富士苹果套袋率在山东和陕西主产区超过75％，每亩套袋量8000～18000个，纸袋投资270～1100元，占生产总投入比重的1／3，占生产资料平均投入的45％；而套袋和摘袋雇工成本在人工成本中占主要部分，套袋对苹果生产投资结构产生了巨大影响。对乔砧密植园大量套袋苹果树进行光合测定发现，套袋造成了投影部位5片以上叶子遮光，无论树冠外围还是内膛，被遮光的叶片净光合速率均为负值，大量套袋极显著降低了树冠中部和内膛照光叶片的光合能力。有关果实套袋技术的应用应该根据市场和生产条件细分确定。

The bagging technique has been applied wildly in fruit production, especially for Fuji apples with a bagging rate of over 75% in main production areas of both Shandong and Shaanxi. 8 000 - 18 000 bags have been used annually, costing 270 - 1 100 yuan per 667 m^2. The cost took up 1/3 of the total investment and 45% of production material input. The labor cost in bagging and bag-removing accounted for main sector of the total labor cost. Therefore, the bagging has strongly influenced the structure of production investment. In the research on photosynthesis of bagged apple trees, it was found that a bag could cause the shading of 5 leaves nearby, with the Pn values of the shaded leaves being negative. Mass bagging could reduce the photosynthetic ability of the middle and interior parts of the canopy very significantly. It is wise to apply the bagging technique based on both the market demand and local production conditions.