Studies on the absorption of nutrient elements in muskmelon. VIII

Abstract

1. To clarify the suitable physical properties of bed soil for muskmelon cultivation, six plots which consisted of factorial combinations of two sizes of clod (0<diam._??_2mm and diam. =3-6mm), and three kinds of soil conditioner (not added, 0.05% poval and 12% manure) were established, and effects of these treatments on the growth, the fruit weight and quality, and the nutrient absorption of muskmelon were investigated.2. With 3 to 6mm clod, the growth of plant as measured by the dry weight of the whole plant, the fruit weight, and the accumulations of phosphorus, calcium and magnesium in the whole plant were slightly increased as compared with the case of using the clod (0<diam. _??_2mm). Manure application (12% by weight) to the soil consisted of both sizes of clod markedly decreased the growth of plant, the fruit weight, the concentration of 2 % acetic acid soluble calcium, and the accumulations of nitrogen and calcium in the whole plant. On the contrary it markedly increased the concentrations of NO3-N, available phosphorus, exchangeable potassium and magnesium, and the electrical conductivity of the soil.As far as this experiment concerned, poval application to the soil consisted of both sizes of clod did not affect the physical properties of soil, so that the growth of plant, and the weight and quality of fruit seemed to be not influenced.3. The interaction of clod size and soil conditioner was observed in the growth of plant, the fruit weight, the soluble solids and external appearance of the fruit, the calcium concentration, and the accumulations of nitrogen, phosphorus and calcium in the whole plant. That is, the means of the fruit weight in the plots of S-N, L-N, S-P and L-P were 797, 774, 805 and 785g, respectively, on the contrary those in the plots of S-M and L-M were 338 and 538g, respectively.The interaction of clod size and soil conditioner on the other effects was the same as the one above.Judging from these results, in the case of using the clod (0<diam. _??_2mm), the concentration of soluble salts in the soil must be kept in a low degree.4. To clarify the relations between larger sizes of clod and fewer volumes of manure, nine plots which consisted of factorial combinations of three sizes of clod (diam. =3-6mm, 10-15mm and 30-35mm), and three levels of manure application (0, 3 and 6% by weight) were established, and effects of these treatments on the growth, the fruit weight and quality, and the nutrient absorption of muskmelon were investigated.5. With 3 to 6mm clod, the growth of plant as measured by the dry weight of the whole plant, and the fruit weight were slightly increased as compared with the case of using the larger sizes of clod. The soluble solids and external appearance of the fruit were not affected by clod size.6. Though the accumulations of phosphorus and potassium of the whole plant were slightly increased with increasing the application amounts of manure, the growth of plant, and the weight of fruit were not increased, nor the quality of fruit was improved.Judging from these results, the suitable clod size for muskmelon cultivation seemed to be 3 to 6mm in diameter.