Developmental studies on weed control method by mulching recycled paper.

本研究的目的是(1)促进水稻水田直播出苗和育苗，(2)弄清主要杂草的光合作用特性，(3)探索再生纸覆盖直播的可能性。(1)在播深2 cm，淹水3 cm的条件下，研究了过氧化钙(CaO2)包衣种子的发芽和出苗情况。在CaO2中添加1%的硼酸(H3BO3)和/或六水合硝酸镁(Mg(NO3)2)，出苗率高于单独使用CaO2。这两种药剂的药效似乎是H3BO_3消毒了种子周围的土壤，而Mg(NO_3)_2为种子提供了氧气和养分。(2)我们准备了主要杂草在水中的光和光合作用曲线，并检测了呼吸速率和光合作用总量相同时的照度(补偿点的照度)。结果表明，当遮光90%左右时，杂草不能生长。(3)纸覆膜直播最重要的一点是要确保纸和土壤牢固地粘在一起，为此，应认真做好土壤的淤泥和平整工作，使土壤表面尽可能平坦。灌水深度以1厘米或以下为宜。这是因为播种后，纸片会浮出水面，如果水太深，就会遮蔽秧苗。因此，这将对他们的成长产生不利影响。

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.