Effects of Soil Surface Strength and Soil Microorganisms on Emergence and Establishment of Moisture-Adjusted Soybean Seeds

Abstract

We examined the effect of the use of moisture-adjusted soybean seeds on seedling emergence and establishment, and investigated the factors that inhibited their emergence during Japan’s rainy season or in upland paddy fields. The decreased emergence rate was attributed to imbibition damage, soil microorganisms, and soil surface strength. The emergence rate of moisture-adjusted seeds was markedly higher than that of low-moisture seeds at high soil moisture levels or high soil surface strength. However, it was often lower in fields that had been flooded for a long period after sowing. Even under such conditions, however, a combination of moisture-adjustment and fungicide treatment of seeds improved the emergence rates. Since emergence-decreasing factors vary with the sowing season and year, and are difficult to predict that, however, the combined use of moisture-adjusted seeds and seed treatment with fungicides may be effective in raising emergence and establishment rates in the fields.