暗沟有哪些优点?我们这里滨江临海,雨水较多,棉田排水降湿是个大问题。为了解决这个问题,我们于1975年秋播时,和九总农科站分别在五个生产队进行了开沟对比试验。在这五组试验中,除开沟方式不同外,其余土质、施肥水平、栽培措施等都相同。去年秋播时,我们用的是一种瓦质涵管,长50厘米,直径24厘米,埋入田中出水处离地表1米,进水处离地表80厘米。成本较低,使用长久。实践证明,这里开暗沟种麦植棉都能增产,沙土地也能开暗沟。暗沟能排能灌,解决了明沟难以解决的矛盾,主要有六大优点:(1)由于排水速度快,地下水位低,能有效地降低“三水”;(2)暗沟地下灌水,使全田干湿均匀,速度快,用水少,克服了土壤板结 What are the advantages of underdrains? Here we Binjiang Linhai, more rain, wet cotton drainage is a big problem. In order to solve this problem, we conducted a trench-ditch experiment with five production teams at nine agricultural stations in the autumn of 1975. In these five groups of experiments, except for the different ways of ditching, the remaining soil quality, fertilization level and cultivation measures are the same. Last autumn broadcast last year, we used a tile quality culvert, 50 cm long and 24 cm in diameter, buried in the field effluent 1 meter above the surface, water 80 cm above the surface. Lower cost, long-term use. Practice has proved that here open undergrowth wheat plantation cotton can increase yield, sand can open ditch. There are six main advantages: (1) Due to the fast drainage speed and low underground water level, “Sanshui” can be effectively reduced; (2) Undercut irrigation can make the whole Tian wet uniform, fast, less water, to overcome the soil compaction