Abstract: A field experiment was conducted with different transplanting densities(45×104,30×104,22×104 hills/ha for early rice;30×104,22×104,16×104hills/ha for late rice) and number of seedlings per hill(4,3,2 for early rice and 3,2,1 for late rice) by using Luliangyou 996(early rice) and Yliangyou 86(late rice) as the ex-perimental materials on the basis of cost-saving cultivation. The result showed that the effect on photosynthetic rate were that the number of seedlings per hill were higher than the transplanting densities than their mutual effects,the early and late rice couldget the high value of photosynthetic rate and solar radiation interception rate of canopy at 45×104hills/ha,3 see-dlings per hill for early rice and 22×104hills/ha,2 seedlings per hill for late rice. The treatment for early rice with 45×104hills/ha and 3 seedlings per hill had a significant reduction of rice canopy tem-perature in hot season,the treatment for late rice with 22×104hills/ha and 2 seedlings per hill could add canopy temperature in cool sea-son. The increase in transplanting density and planting seedlings per hill rate improved the yield of early and late rice but the transplanting densities or planting seedlings exceeds a certain value the yield would decline. The opti-mal transplanting densities and planting seedlings for double-season early rice was respec-tively with 33×104hills/ha and 3 seedlings per hill and 26×104hills/ha and 1 seedling per hill for late rice could obtain high yield.

Key words: Rice, Transplanting density, Number of seedlings per hill, Canopy

CLC Number: 

• S511. 01