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一、为什么要营造农田防护林在经常遭受风沙、干旱、霜冻等自然灾害的地区,为保护农田不受自然灾害侵袭,给农作物创造良好的生育条件,保障农作物正常生长发育而营造的防护林,叫农田防护林,简称护田林。它有降低风速,固定流沙,阻挡飞雪,调节气候,改善农业生产条件,保障农作物高产稳产等功用,是一项重要的农田基本建设。在护田林保护下的农田和牧场,一般可以降低风速30～60%,减少水分蒸发量10～40%,增加相对湿度10～30%,降低气温0.7～2.3℃(冬季)以至8～10℃(夏季),延长无霜期10天左右;可以增加粮棉产量20～40%,增产瓜菜50～70
I. Why shelterbelts for farmland protection In areas where natural disasters such as sandstorms, droughts and frost often suffer, to protect the farmland from natural disasters, to create good conditions for crop growth, and to protect the normal growth and development of crops, shelterbelts called farmland Shelterbelt, referred to as retaining Tianlin. It has the function of reducing wind speed, fixing quicksand, blocking blizzard, regulating climate, improving agricultural production conditions, and ensuring high and stable crops. It is an important farmland capital construction. The farmland and pasture under the protection of paddy field can generally reduce the wind speed by 30-60%, reduce the water evaporation by 10-40%, increase the relative humidity by 10-30%, decrease the temperature by 0.7-2.3 ° C (winter) and 8-10 ° C (Summer), frost-free period of about 10 days to extend; can increase the yield of grain and cotton 20 ~ 40%, yield 50 ~ 70