Production of rice for whole crop silage using manure in Itoshima Region, Fukuoka prefecture

The cultivation area of rice for whole crop silage (WCS) has rapidly increased in the last decade in Japan due to increasing demand for domestic livestock feed as well as a measure for the use of redundant paddy field. On the other hand, the production cost of rice for WCS is largely supported by subsidy now, so it is required to reduce the production cost. Manure application is a prospective way to reduce the cost of fertilizer and to sustain soil fertility. Thus, we investigated the production of rice for WCS using manure in Itoshima region, Fukuoka Prefecture, Japan, from the aspects of soil fertility, plant growth, and dry matter weight. The fields where manure was applied showed relatively high TN contents in soil whereas fields where manure was not applied showed low TN contents. This result indicated that soil fertility can be deteriorated by the continuous production of rice for WCS when organic matter is not supplied by manure and other materials. Plant length (r=0.748^∗) and tiller number (r=0.891^∗∗) at panicle initiation stage were closely correlated with TN content in soil whereas SPAD readings (r=0.846^∗∗) at the same stage was closely correlated with mineralized N in soil. Dry matter weight was positively correlated with TN content in soil (r=0.767^∗∗). Fields where manure was not applied had small dry matter weight although nitrogen was supplied from fertilizer. These results indicated that dry matter weight was significantly affected by soil fertility.