Ecological Efficiencies of Energy Conversion in Pasture : VI. Changes in calorific values of several pasture plants and energy storage in grassland

Abstract

In order to obtain basic data for clarifying energy passage in a grassland ecosystem, determination of calorific values were carried out on several species under various conditions. Furthermore, energy storage in plant materials on a unit land area were calculated to ascertain the dynamics of energy mass in a pasture system and to compare variations between different pasture systems. The results obtained are as follows ; 1) Yearly averaged calorific value on a DW g basis was 4, 301 cal for orchardgrass in a cutting system, and 4, 375 cal (light grazing plot) and 4, 369 cal (heavy grazing plot) for a mixed community of grasses and legumes in a grazing system. 2) Leaf blade possessed the highest energy value among the components of orchardgrass. 3) Calorific values among six dominant species examined in grazing grassland show decreasing tendencies in a Zoysia japonica>white clover≒Kentucky bluegrass≒Sasa nipponica>red top≒orchardgrass>tall fescue sequence. 4) Estimated energy storage on a unitgro und area basis was high in grazing pasture (ranging from 4, 100 to 7, 600Kcal/m^2 for the light grazing plots, from 2, 800 to 6, 000Kcal/m^2 for the heavy grazing plots), however, values for an orchardgrass cutting field ranged from 1, 900 to 4, 100Kcal/m^2.