Abstract
Soil erosion due to rainfall is a serious problem in acid soil region in subtropical Japan. Introducing new crops which can be used in rotation with sugarcane and pineapple is expected to alleviate soil erosion. We developed a buckwheat cultivation method suitable for acid soil with pH 3.9∼4.2 in subtropical Japan. We examined the effects of composted manure and dolomite on the growth and grain yield of buckwheat. The composted manure was applied at a rate of 1∼3 g m-2 and dolomite at the rate of 200 and 500 g m-2. Application of composted manure significantly increased grain yield and shoot weight. Grain yield was 171∼235 g m-2 when composted manure was applied, whereas 75∼104 g m-2 when neither composted manure nor dolomite was applied. Shoot weight was 174∼291 g m-2 when composted manure was applied, but 95∼100 g m-2 when neither composted manure nor dolomite was applied. The amount of shoot obtained in the experiment by applying composted manure is considered enough to substantially decrease soil erosion caused by rainfall, if the shoot is used for mulch to cover soil surface. No significant effect of applying dolomite on grain yield and shoot weight was detected. Applying composted manure significantly elevated soil pH, which did not exceed pH 7 at which pineapple growth would be damaged.
