Studies on mal-emergence on direct sowing of culture of rice on well-drained and unleveled paddy field
2003
Arihara, K. (Chiba-ken. Agricultural Experiment Station (Japan)) | Iwabuchi, Y. | Koyama, Y.
Summary The purpose of this study is to show that the causes of mal-emergence in direct sowing culture on unleveled well-drained paddy field in the early season culture in the in the temperate warm area. 1. The high incidence of mal-emergence was ascertained on the surface lower area in the direct sowing culture. 2. The water logging, compared with on the right after sowing, has an effect on the mal-emergence on the first emergence time, and the emergence rate fell sharply down in the water logging at least for two days. . 3. Cods were broken down by impact of rainfall and being soaked in the water logging. Thereby structural crust was formed on the surface, and its hardness increased together with decreasing of water content of soil. The hardness was 1.5Mpa at 25% of water content, and at least 1.8Mpa the emergence rate fell sharply. 4. The causes of mal-emergence on the lower point were low air permeability in the water logging and the hardness of structural crust at lower soil water content, the reason of which was a scarcity of capillary water of hard pan. It is concluded that it is necessary to make the ground level flat and to improve the hard pan.
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