Studies on the composts for raising seedlings of vegetable crops in hot beds

Abstract

There has been no standard method in making compost for raising tomato seedlings in hot beds in Japan. The usual practice is to pile organic mate-rials, fertilizers and soil in alternating layers during summer. To get a uniform mixture, the stack is turned orthogonally two or three times in autumn and winter. Because of this practice nutri-ents are leached by rainfall during this period of about 6 months, and much labor is required for piling and turning of the compost. Experiments were conducted during 1955_??_1959 to find easier and more rapid ways of making com-post. Tomato variety “Kurihara” was planted in the greenhouse in many types of composts made with various combinations of organic materials, soil conditioners, inorganic and organic fertilizers, and soils. The composts used in this study were made immediately before use. 1. Of the soils tested for making compost, vol-canic ash soil was better than either clay loam (Arakida) or sand because of its superior physical properties. Leaf mold from broad leaf trees was a better organic material than either rice straw ma-nure or peat moss. The best results were obtaind from mixtures of organic material and soil in the ratio of 1 to 1 in volume. No effects were observed of sieving of organic materials or addition of soil conditioners or sand to the compost. 2. The use of soy bean, rape seed and fish oil cakes, and rice bran, commonly used as fertilizer in Japan, in the rapid-made compost is discouraging because the decomposion of these materials injured the seedlings. Also when calcium cyanamide was used serious injury to the seedlings occurred. This was probably due to the decomposition of calcium cyanmide to dicyan-diamide. The best source of nitrogen is from ammonium sulphate or urea. Injury was produced at higher rates of nitrogen than 430-870g N per cubic Ken (about 6000l) in volcanic ash soil and leaf mold in 1 to 1 ratio. Good growth of seedlings was obtained when 4300g of P2O5 per cubic Ken from super phosphate or fused phosphate was added. However, larger quantities of phos-phates produced no injury. Fertilization with K2SO4 and KCl at the rate of 430-870g K2O per cubic Ken, gave excellent growth but higher rates pro-duced poor seedlings. 3. Field experiments were carried out in 1958_??_59 at the Tokyo University farm at Tanashi. Tomato Variety “Furuya-wase” was sown in hot beds in the ordinary compost and in the rapid-made compost of volcanic ash soil and leaf mold (1 to 1 ratio) with optimum quantities of N, P2O5 and K2O. These seedlings were transplanted to the field and grown to maturity. The early and total yields showed no significant difference in the two treat-ments indicating that the rapid-made compost was the same as the ordinary compost.