延安地区从1978年开始推广“四法”种田,去年已发展到264万亩,占到总播种面积的50％,5年来,累计可增产粮食4亿多斤。“四法”种田的具体做法如下。一、山地水平沟种植法。适用于25度以下的山坡地,宜种谷子、小麦、豆类,薯类等作物。从坡地的上部耕起,沿等高线开沟,肥料集中施于沟内,后用畜力单双行播种机或木耧适量播种,覆土镇压。开沟是关键环节,先用山地犁水平开沟,再用耩子套耕一次,使沟深达到6-8寸,外高成垄,内低成壕,形成水平沟条带状。沟距一 Yan’an started to promote the “four methods” of farming since 1978, having grown to 264 million mu last year, accounting for 50% of the total sown area. Over the past five years, it has been estimated that more than 400 million kilos of grain will be produced. The specific practices of “four laws” farming are as follows. First, the level of furrow cultivation method. Suitable for slopes below 25 degrees, suitable for millet, wheat, beans, potatoes and other crops. From the top of the slope plowing, ditching along the contour line, fertilizer concentrated in the ditch, after the use of animal power single or double sowing machine or mound sowing, covering soil suppression. Ditch is the key link, first with the horizontal plow ditch plow, and then plowing a set of furrows, the groove depth of 6-8 inches, the outer ridge into a ridge, the formation of horizontal trench strip. Furrow one