Effect of Dehydrated Digested Effluent of Manure on Yield and Quality of Annual Forages and Soil Chemical Properties in Southern Kyushu, Japan

Abstract

Digested effluent of manure (DEM) produced by biogas-plants contains many macro- and micro-nutrients. In an experiment conducted in southern Kyushu (Japan), forage crops cultivated after receiving DEM and chemical fertilizers exhibited similar dry matter yields. From a logistical standpoint, however, DEM in liquid form is difficult to handle and apply due to the low concentration of nutrients. To overcome this shortcoming, we prepared dehydrated DEM (DDEM) by adding DEM to cattle manure without disturbing the manure fermentation process. The objective of this research was to evaluate the effect of DDEM on dry matter yield and nitrogen recovery rate in annual dual-cropping systems (summer crop of maize or sorghum and winter crop of Italian ryegrass) that are typical of the region and to compare these results to commercial cattle manure alone, in combination with chemical fertilizer (CM or CM + CF), or no fertilizer application (NF). In both cropping systems, the DDEM treatment produced similar dry matter yields (2.6 to 3.02 kg &middot m - 2 ) and apparent nitrogen recovery rates (43% to 53%) as the CM + CF and CM treatments. This suggests that DDEM can potentially replace chemical fertilizers and commercial cattle manure in the region.