Study on Appropreate Seeding Density and Levelling Accuracy of Paddy Field Surface in Direct Seedling of Paddy Rice.

水稻直播育秧适宜播种密度及田面整平精度的研究。

• 批准号: 08456117
• 负责人: YAMAJI Eiji
• 金额: $ 3.9万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08456117/
• 关键词: Large-sized Paddy Field; Direct Seeding; levelling; Density of Seeding

Direct seedling method in large-sized paddy field should be researched for low-cost rice production in Japan. Our research was focused on the heterogenity of germination caused by bad levelling of the field and that if growing caused by seedling density.In the second year, we continued experiments done in the first yearand made new ones.1) Popurarity of several direct seedling methodsDirect seedling methods are categorized as DS in dry field, DS in ponding field and DS in wer field. Three methods are compared, i. e. the distribution of three methods is surveyed and the reason is estimated.2) Heterogenity of germinationDirect seedling in large-sized paddy field is surveyed, and the data of levelling, groundwater, soil moisture, seedling method and germination condition are collected. Then, in the artifitial weather chamber, germination experiments were done in various conditions of soil, water and seedling conditions.3) Soil hardness of drained field just after puddingIn the artifitial weather chanber, drying process is pursued in various levelling conditions. This result well be utilized for the estimation of the submergence distance of seed, which is an important factor of germination.4) Experiment on relations between seed density and growth shows the existence of optimum density of seeding.5) To apply direct seeding for large-sized paddy field, more precise levelling is neede.After these experiments and discussions, we've found the problems of direct seedling and directions for the improvement

日本水稻低成本生产应研究大面积直播法。本试验主要研究了由于田间平整不良引起的种子发芽的不均一性和由于秧苗密度引起的种子生长的不均一性，第二年在第一年试验的基础上，又进行了新的试验。1）几种直接育苗方法的流行性直接育苗方法分为旱地DS法、积水地DS法和水田DS法。对三种方法进行了比较，即：e. 2）发芽异质性对大面积稻田直播进行了调查，收集了平整、地下水、土壤水分、育苗方法和发芽条件等资料。在人工气候室中，进行了不同土壤、水分和幼苗条件下的发芽试验。3）刚发芽后排水田的土壤硬度在人工气候室中，在不同的平整条件下进行干燥过程。4）种子密度与生长关系的试验表明，存在最佳播种密度。5）在大面积水稻直播中，尼德进行更精确的平整。找出了直接育苗存在的问题及改进方向