怀集县林科所在创造撩壕种杉六年成材的基础上,对撩壕的整地方法作了进一步的研究和改进。经过改进了的撩壕整地方法,既与大撩壕一样能确保土、肥、水和造林后不用抚育的优点,又能节省50%以上的劳动力。过去挖撩壕一亩需要40-50个工,现在每亩只化20个工就够了。这种新的整地方法,是学习了“优选法”得到启发,而进一步试验出来的°他们将挖大撩壕改为筑大撩壕。做法是:先用草皮泥筑一条撩壕基,然后挖平壕底,将黄土填在基边(图一),再将撩壕上的表土填入 On the basis of six years of creation of the trenches and the establishment of forestry in Huaiji County, further research and improvement were made on the method of soil preparation. The improved method of trenching and earth preparation, together with the large trenches, ensures the benefits of soil, fertilizer, water and afforestation without reforestation and saves more than 50% of the workforce. In the past, it took more than 40-50 workers to dig a mu of mu, and only 20 workers per acre were enough. This new method of land preparation was inspired by the study of “law of preference,” and further tests were carried out. Instead, they were going to dig a big trowel instead of a big trowel. The approach is: first with a turf mud build a trench trench foundation, and then dig trenches at the bottom of the loess fill (Figure I), and then fill the topsoil into the trench