Rice cultivation by the transplanting of infant seedlings was investigated in Ibaraki Prefecture. The results were as follows:
1) All the farmers used rockwool mats, while they have had different practices such as sowing rate, quantity of irrigation water, nursery period and so on. Days from sowing to the transplanting of seedlings varied from 10 to 20, and leaf age at transplanting from 2.4 to 3.2. Plant length of seedlings at transplanting was more than 8.0cm.
2) The average number of planted seedlings per hill was from 6.1 to 8.4. This figure was higher and variable than the usual one, 4 to 5. Higher percentage of vacant hill was brought about by higher fluctuation of the number of planted seedlings per hill.
3) The time needed for the rearing of infant seedlings was reduced to 49% of that for the rearing of young seedlings. But replanting time for infant seedling cultivation required 72% more than that of young seedling cultivation, because of high rate of vacans hill in infant seedling cultivation.
4) Rice yield in the infant seedling cultivation was nearly the same as that of young seedling cultivation. It is expected that low cultivation cost in infant seedling cultivation will be achieved by means of the improvement of transplanting accuracy.
