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冬水田,是陕南丘陵地区在水源缺乏、灌溉设施较差的情况下,形成的一种稻田土壤类型。主要特点是:土壤长期渍水;团聚体高度分散;经常处于以还原体系为主的生物土壤环境条件;作物一年一熟。冬水田对水稻保插保收具有重要作用,但在气候失调,降水稀少,冬春干旱的年份里,往往因缺水而倒旱(起旱)致使水稻插秧后迟迟不能返青分蘖,发生严重的坐蔸现象。不仅影响当年产量(一般减产100—200斤,严重的减产一半多),而且要经过2—3年后才能恢复地力。所以有“一年倒旱,三年减产”的说法。倒旱后引起水稻坐蔸的原因是多方面的,如土壤缺少有效磷、氮养分,土壤硫化物对根系的毒害,某些有机酸浓度过高,
Winter paddy fields, is a hilly region in southern Shaanxi lack of water, poor irrigation facilities, the formation of a paddy soil type. The main features are: long-term soil waterlogging; highly dispersed aggregates; often in the reduction system of biological soil-based environmental conditions; crops a year cooked. Winter paddy fields play an important role in maintaining paddy rice crop coverage. However, in the years of climatic imbalance, scarce precipitation and winter and spring drought, drought often occurs due to water shortage (drought), which results in the delay of tillering and serious occurrence of rice after transplanting Sit sitting phenomenon. This will not only affect the current year’s output (typically 100-200 kg, a serious reduction of more than half), but it will take 2-3 years to restore the soil. Therefore, there is “one year drought, three years of production cuts” argument. The causes of rice sitting after drought are many. For example, the soil lacks available phosphorus and nitrogen nutrients and the soil poisones the root system. Some organic acids are too concentrated,