|Budget Amount *help
¥6,100,000 (Direct Cost : ¥6,100,000)
Fiscal Year 1997 : ¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1996 : ¥3,900,000 (Direct Cost : ¥3,900,000)
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 methods
Direct 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 germination
Direct 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 pudding
In 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