Effects on growth and yield in sparse-planting paddy rice [Oryza sativa] of plant type and manuring

1) To clarify characteristics of growth and yield of sparsely planted paddy rice, the sparse planting test of the cultivars of different plant types, that is, "Harebare" and "Koganebare", was carried out, adopting three types of methods of fertilizer application. The planting density in the sparse planting plot was 11.1 plants/square meter, and that in the control plot was 19.6plants/square-meter. 2) The number of stems per plant was larger in the sparse planting plot than in the control plot, but the number of stems per square meters was larger in the control plot than in the sparse planting plot. However, there was little difference in the number of ears between the two plots. The percentage of productive panicles was higher in the sparse planting plot. The number of stems of "Harebare" increased when the amount of additional manure was increased, but in the case of "Koganebare" such change due to the difference of the method of fertilizer application was not clearly observed. 3) The number of grains per ear in the sparse planting plot was larger, and consequently, the total number of grains per unit area in this plot was larger than that in the control plot. The percentage of ripened grains of "Harebare" was lower in the plot where the larger amount of additional manure was applied to increase the number of ears and the total number of kernels, buy that of "Koganebare" was higher in the sparse planting plot than in the control plot. The 1000 grains weight, of fully ripened kernel was larger in the control plot than in the sparse planting plot in both the cases of "Harebare" and "Koganebare". With regard to the yields, it was larger in the control plot than in the sparse planting plot in the case of "Harebare", but there was little difference between these two plots in the case of "Koganebare"