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二、水稻土的管理(一)稻田排水在我国的一些冲积或湖积平原上的水稻土,一般土壤质地偏粘,砂粒甚少.原母质的透水性较差,随着复种指数的不断提高和要求稻、麦高产,稻田排水已成为最重要的增产措施之一.研究表明,排水能改善土壤的通气状况,增加根系活力,有利稻麦增产.如植稻淹水期间,短期排水烤田可使根层的通气孔隙田增加1—5%到10%以上,氧化还原电位由负值增至500毫伏;土壤空气中的O_2由5%增10%,CO_2减少约一半;土壤溶液中的O_2近3倍;水稻不同生育期间的白根增多,黑根减少,水稻一般可增产10—20.如前所述,由于早作期间土壤水一般过多,故旱作土壤排水更为重要.据浙江,上海以及江苏等研究,开挖深暗沟或埋暗管,结合明或划线沟均能迅速排除田面积水和降低地下水位,在春季多雨时可使旱作增产40%左右.一般春雨期间也可增产10—15%、
Management of paddy soils (I) Drainage of paddy Paddy soils on some alluvial or lacustrine plains in China generally have a slightly sticky texture and little sand, and the permeability of the original parent material is poor. As the multiple cropping index continues to increase It is one of the most important stimulation measures to increase the yield of rice and wheat, and the high yield of paddy field and drainage of paddy field have become one of the most important stimulation measures.Research shows that drainage can improve soil aeration and increase root activity, Can increase the aeration pore field of the root layer by 1-5% to more than 10% and the redox potential from negative value to 500 millivolts; the content of O 2 in soil air is increased by 5% by 10% and the CO 2 by about half; in the soil solution O_2 nearly tripled; white roots increased during different growth stages of rice, black roots decreased, rice can generally increase 10-20. As mentioned earlier, as early as the soil water is generally too much, so dry soil drainage is more important. According to the research of Zhejiang, Shanghai and Jiangsu, excavation of deep-buried ditch or buried ducts, combined with clear or ditched ditch can quickly exclude the field water and reduce the groundwater table, which can increase dry output by about 40% in rainy spring. During spring rains can also increase 10-15%