Possibility of potassium application on grassland in andosol for low-input sustainable agriculture in Hokkaido [Japan]
1996
Saigusa, T. (Hokkaido. Konsen Agricultural Experiment Station, Nakashibetsu (Japan)) | Noshiro, M.
The possibility of potassium application on grassland in Andosol for low-input sustainable agriculture is discussed. The application of 300 kg ha(-1)y(-1) of potassium as an exchangeable fertilizer in 0-5 cm soil has been recommended to maintain high dry matter yield. Eighty out of 300 kg ha(-1) of exchangeable potassium has been required since 220 kg ha(-1)y(-1) of potassium as fertilizer is needed in Hokkaido. In this study, a potassium application test was carried out on a timothy-legume mixture in the Konsen district in order to estimate the feasibility of reduced potassium application. The amount of potassium required to maintain a stable legume ratio, which is important in maintaining grasslands over the long term, was less than that for high dry matter yield. Reduced potassium application made the potassium content of forage lower, the calcium and magnesium content higher, and as a result, the mineral balance of forage better, although it decreased dry matter yield. Eighty kg ha(-1) of Potassium in 0-5 cm soil could not be maintained because of uptake by timothy. Moreover, the amount of exchangeable potassium in autumn decreased until the next spring. It is important to estimate the minimum application of potassium for a stable legume ratio, and to clarify the amount of exchangeable potassium in the soil for stable fertility and conservation of the environment. Potassium application is expected to be reduced on the basis of the results of these experiments
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