Publication Date

1985

Location

Kyoto Japan

Description

Greenhouse experiments and field surveys were conducted (1) to evaluate the S-supplying capacity of soil in Chugoku area, and (2) to determine some diagnostic criteria by which S-status of plants can simply be assessed, and (3) to find out a critical S values in several forage crops. The results obtained are as in the following; 1) The S-supplying capacity of soil is estimated 5mgS/Kg in granite regosols and 58mgS/Kg in andosols. The S-supplying capacity of soil could not be estimated by only available-S content, but may be reliably estimated by total-S and the mineralization rate of organic matter. 2) Grassland soil containing low available-S and less organic matter is so often found here and there in Chugoku area. The S-defficiency of forage crops may easily occur in thses grasslands if they are supplied no or a less amount of S. 3) The concentration of SO4-S in leaves can be used as an index of S-status of plants, instead of SO4-S/total-S value or N/S ratio. 4) The critical values of SO4-S in the leaves for producing 60% of their maximum yields is 60 to 160ppmS, the lowest in Siratro, Sorghum, African millet and Perennial ryegrass, and 230 to 260ppmS, low in White clover and Desmodium, and 450 to 880ppmS, higher in Orchard grass, Red clover, Italian ryegrass and Tall fescue, and 1400ppmS, the highest in Alfalfa.

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Studies on the Sulfur Nutrition of Forage Crops

Kyoto Japan

Greenhouse experiments and field surveys were conducted (1) to evaluate the S-supplying capacity of soil in Chugoku area, and (2) to determine some diagnostic criteria by which S-status of plants can simply be assessed, and (3) to find out a critical S values in several forage crops. The results obtained are as in the following; 1) The S-supplying capacity of soil is estimated 5mgS/Kg in granite regosols and 58mgS/Kg in andosols. The S-supplying capacity of soil could not be estimated by only available-S content, but may be reliably estimated by total-S and the mineralization rate of organic matter. 2) Grassland soil containing low available-S and less organic matter is so often found here and there in Chugoku area. The S-defficiency of forage crops may easily occur in thses grasslands if they are supplied no or a less amount of S. 3) The concentration of SO4-S in leaves can be used as an index of S-status of plants, instead of SO4-S/total-S value or N/S ratio. 4) The critical values of SO4-S in the leaves for producing 60% of their maximum yields is 60 to 160ppmS, the lowest in Siratro, Sorghum, African millet and Perennial ryegrass, and 230 to 260ppmS, low in White clover and Desmodium, and 450 to 880ppmS, higher in Orchard grass, Red clover, Italian ryegrass and Tall fescue, and 1400ppmS, the highest in Alfalfa.