Abstract
In Japan, it has become apparent that imbalances such as excessive phosphate and potassium in the soil due to over-fertilization in upland fields and greenhouses, along with soil fertility decline in paddy fields caused by insufficient application of organic matter and silicate fertilizers is leading to a marked polarization of soil fertility. This is part of the reason that livestock manure compost has been applied as a soil amendment rather than as a fertilizer in the upland fields. In addition to this, due to low rice prices and a shortage of manpower, the amount of compost and silicate fertilizer applied to paddy fields, which require compost, has been drastically reduced. Biomass resources produced in Japan, such as livestock manure, sewage sludge, and food waste, contain fertilizer components that far exceed the amount of nitrogen, phosphate, and potassium in the chemical fertilizers used in Japan. Before now, biomass resources were mainly used as compost. However, in the future, it will be necessary to develop and promote the use of fertilizers that look and feel like existing ones. Organic farming, which relies solely on organic matter, may contribute to nutrient imbalance in the soil. To prevent this from happening, it is essential to use chemical fertilizers in combination, which can adjust the amount of fertilizer components applied at any given rate.
