Abstract
We examined the effects of the stage of maturity of cattle manure compost and the timing of application on the N-fertilizer effect in forage rice. Rice plants were grown in several plots to which cattle manure compost of different stages of maturity was applied 0-4 weeks before soil puddling. In plots that received compost early or that received mature compost, the N concentration of the puddled-soil solution and the amount of N uptake by the rice plants were low. When compost at the midpoint of the first fermentation was applied just before soil puddling, rooting was delayed by a few days. However, there was no damage to the growth of the rice in any plot, and the whole crop yield was high (depending on the uptake of N). Yield was resistant to delays in rooting or to improper N supply, because the whole plant is harvested for forage, not just the grain. In addition, the degree of nitrate leaching into the subsoil was low when the compost was immature or was applied late. Consequently, in forage rice cultivation, cattle manure compost can be a highly effective N fertilizer if it is applied after the first fermentation and near soil puddling.
