Developmental studies on weed control method by mulching recycled paper.

本研究的目的是：(1)促进水田淹水直播的出苗和成苗；(2)明确主要杂草的光合特性；(3)探索覆盖再生纸直播实现的可能性。(1)在播种深度为2 cm、淹水为3 cm的条件下，用过氧化钙（CaO2）包被几种化学药剂，研究了种子的萌发和出苗情况。在CaO2中添加1%硼酸（H3BO3）和/或六水硝酸镁（Mg (NO3) 2）时，出苗率高于仅添加CaO2。H3BO3对种子周围的土壤进行了灭菌，而Mg (NO3) 2则为种子提供了氧气和营养。(2)制备了主要杂草在水中的光照和光合作用曲线，测定了呼吸速率和光合作用量相等时的照度（补偿点的照度）。结果认为，如果90%的光线被遮蔽，杂草就无法生长。(3)采用覆膜直播时，最重要的一点是保证纸与土的粘牢。为此，应认真做好土壤搅和找平工作，使土壤表面尽可能平整。灌溉水应在1厘米深或更少。这是因为如果水太深，播种后纸片会浮出水面，给幼苗遮荫。因此，这将对它们的增长产生不利影响。

The objectives of this study were (1) to promote seedling emergence and establishment on the direct sowing in flooded paddy field, (2) to make clear the characteristics of photosynthesis on main weeds and (3) to pursue the possibility of realization on the direct sowing with mulching recycled paper.(1) We investigated germination and seedling emergence on seeds coated with calcium peroxide (CaO2) adding several chemicals under the conditions of 2 cm sowing depth and 3 cm flooding.When boric acid (H3BO3) and/or magnesium nitrate hexahydrate (Mg (NO3 ) 2) were added 1% to CaO2, percentage of seedling emergence was higher than only CaO2. This efficacy of both chemicals was seemed that H3BO3 sterilized soil around a seeds and Mg (NO3) 2 supplied oxygen and nutriment for seeds.(2) We prepared the light and photosynthesis curves in water of main weeds and examined the illuminance at the respiration rate and amount of photosynthesis became the same (illuminance at the compensation point) . The results was considered that no weed would be able to grow if about 90% of the light was shaded.(3) The most important point in using the paper mulch direct sowing was make sure that the paper and soil stick firmly to each other.For this purpose, it should do soil puddling and leveling work carefully to make soil surface as flat as possible. And the irrigation water should be 1 cm deep or less. This is because pieces of paper will rise to the surface after sowing and shade seedling if the water is too deep. Thus, this will affect their growth adversely.