Abstract:A new method is used to determine the nitrate-nitrogen content in organic fertilizers which contain large amounts of ammonia, colored organic matter, and colloidal substances that can not be removed by usual methods.In this method the nitrate is reduced into nitric oxide by ferrous chloride and thus removed from the impurities, and then converted back into pure nitric acid by air and hydrogen peroxide. The nitric acid formed is determined by the usual phenoldisulfonic acid method.

Abstract:Investigation was conducted to study the effect of soil-moisture content in relation to the growth-rate of tong-oil-tree seedlings. Pot culture, which was separately filled with sand, loam and clay soil, was used. Both of directseeding and transplanting was tested. Three treatments of moisture content for these pots filled with sand and loam were 50%,80%,and saturated, respectively. Four treatments of moisture content were made for the clay soil.These were 40%,60%,80%,and saturated, respectively.