自本世纪三十年代开始,美国苹果栽培株数减少,而总产量却增加,其原因主要是栽培技术的改进,导致株产大幅度增加。美国促进苹果高产。稳产所采取的主要技术措施有如下几点: 一、采取多种途径,努力发展矮化密植栽培,这是美国苹果增产的重要途径和发展方向,也是美国苹果栽培方式上的_个重大变革。长期生产实践证明:在一定 Since the 1930s, the number of cultivated apple trees in the United States has decreased while the total output has increased. The main reason for this is the improvement of cultivation techniques, resulting in a substantial increase in plant production. The United States to promote high-yielding apples. The main technical measures taken to stabilize the production are the following: First, take a variety of ways and strive to develop dwarf dense planting cultivation, which is the United States an important way for apple production and development direction, but also the United States on the apple cultivation _ a major change. Long-term production practice proved: in a certain