Phonevilay et al., 2013. Livest. Res. Rural Dev. 25 (1), Article #15

The aim of this study was to evaluate the effect of potassium nitrate on methane production from the leaves of a range of fodder trees (Jack fruit [Artocarpus heterophyllus], Muntingia calabura, Leucaena leucocephala, Gliricidia sepium, Mimosa pigra and Acacia auriculoformis) an in vitro incubation system. The incubation was for 24 h with measurements of total gas and per cent methane at intervals of 6, 12, 18 and 24 hours and determination of residual unfermented substrate at the end of each interval. Gas production increased with length of incubation (Table 4) and was lower when nitrate was added to the substrate.  Percent methane in the gas and methane production increased with length of incubation and were always lower when nitrate was added to the substrate. The percentage DM solubilized and methane produced per unit DM solubilized  increased with incubation time, varied among the foliages and were lower when nitrate was present in the substrate. In the absence of nitrate, methane production from Mimosa was only some 50% of that from Gliricidia and Jackfruit.  Both percentage DM solubilized at 24h and methane production per unit DM solubilized were linearly and positively related with the solubility of the crude protein (N*6.25) in the foliages.