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低温地区的稻田土质粘重,地下水位高,遇上秋冬多雨年份,油菜移栽后常常发生大量烂根死苗。据湖南益阳地区几个湖区县调查,每年油菜移栽后烂根死苗率约在10%左右,严重年份超过15%,并因此废弃的油菜面积每年也在5%以上。油菜烂根死苗,对产量的影响极大,据我所几年调查证明:烂根死苗率达18.6%,亩产为84.5公斤;烂根死苗率达30.2%,亩产仅67.15公斤;比无烂根死苗的亩产96.65公斤,分别减产12.6%和30.5%。油菜移栽后烂根死苗,其原因除了选地不当、土壤粘重、地下水位高以外,还有稻田排水过迟、湿耕烂整、稀泥移栽,整地粗放、“三沟”不通,天气多雨或大小漫灌等,造成土壤含水量过高,田间滞水,土
Low temperature paddy soil sticky, groundwater level is high, met the autumn and winter rainy years, rape often occurs after transplanting a large number of rotten roots dead seedlings. According to a survey conducted by several lakes and counties in Yiyang, Hunan, the rate of rotten roots and seedlings after rapeseed transplanting is about 10% in each year and more than 15% in severe years. As a result, the area of discarded rape is also above 5% annually. Rape rotten root dead seedlings, great impact on the yield, according to my survey several years to prove: rotten root dead seedlings rate of 18.6%, 84.5 kg per mu; rotten root seedlings rate of 30.2%, only 67.15 kg per mu ; 96.65 kg per mu of dead seedlings without root rot, 12.6% and 30.5% respectively. In addition to improper selection, soil stickiness, groundwater level is high, there are too late drainage, wet tillage, mud transplanting, land preparation extensive, “three ditch” barrier, The weather is rainy or the size of flooding, resulting in high soil moisture, stagnant water in the field, soil