Development of a Water storage-type Deep-irrigation Method for Rice Aimed at Increasing the Environment-protecting Function of Paddy Fields

我们开发了一种深灌方法，在东北地区种植水稻稳定高产的同时，增加了储水功能，这是水田在环境保护中的功能效益之一。促进蓄水功能的主要目的是将雨季融雪水和降雨丰富的河水流入大海的径流推迟到夏季，而夏季往往是供水短缺的时候。我们设计了一个水管理系统，考虑了以下几点：1：为了增加水田的蓄水功能，利用现有的堤防使水尽可能深（最大水深25 - 30厘米）。2：考虑到东北地区的稳定高产，减数分裂阶段的水深为25 - 30 cm，以防止低温。3：在供水稳定的情况下，不断增加水深，直到7月中旬水量充足时，水深控制为只有一个峰值。4：深灌增产，指一位优秀农民采用的深灌增产技术。对水稻植株的生长进行了分析。分层夹灌法的结果表明，深灌法是在水稻植株冠层10cm处进行的。三年的研究表明，控释包衣肥对提高产量是有效的。

We developed a deep-irrigation method to grow rice at a steady high yield in the Tohoku district, while increasing the function of water storage, which is one of the functional benefits of paddy fields in environmental protection. The main objective for the promotion of the water storage function is to delay the runoff into the sea of the river water, which is abundant due to snow-melting water and rainfall in the rainy season, until summer when there is often a shortage of water supply. We designed a water managing system taking into consideration the following points : 1 : To increase the water storage function of the paddy field, the water is made as deep as possible using the present levee (the maximum water depth, 25 - 30 cm). 2 : Considering the steady high yield in the Tohoku district, the water depth at the meiotic stage is made 25 - 30 cm, to protect from low-temperature. 3 : The water depth is increased continuously until mid July when water is abundant, assuming the water supply is steady, and the depth is controlled to have only one peak. 4 : The yield is increased by deep irrigation, referring to the yield-increasing technique of deep-irrigation method used by an outstanding farmer. The growth of rice plants were analyzed. As the result of stratified clip method, it became clear that the deep-irrigation method is put on the rice plant canopy 10 cm. Three years investigations indicated many available results, one of them is that controlled release coated fertilizer is effective in order to increase the yield.