Abstract
1. While the fractions of the chemical compositions assimilated by producing plants are decayed by decomposers, much of these are accumulated in dead organic matter until decayed by decomposers, at rates which vary greatly from place to place. The general differential equation for the rate of change in dead organic matter storage is illustrated by models for builtup and decomposition of organic matter. In order to elucidate energy and nutrient flow through the decay system in the Sasa paniculata type grassland in Kamishihoro, these models are applied. 2. In the case of decomposition for organic compositions on the grassland floor, the F layer is clearly dominant, while the H layer is dominant in the grassland floor in terms of mineral nutrient standing states. 3. The increasing order of decay rate parameters for organic chemical compositions in the litter is crude protein, lignin, other carbohydrate, hot water soluble fractions, cold water soluble fractions, crude fat and pure cellulose and turnover rate parameters for energy and mineral nutrient elements is K, energy, Ni, Co, Cu, Zn, Ca, Na, N, Mg, Mn, P and Fe. Generally, turnover rate parameters for mineral nutrient elements in the litter are less than decay rate parameters for organic compositions. 4. The time periods required for decomposition or turnover of 50% of initial organic matter, organic C, energy, cold water soluble fractions, hot water soluble fractions, crude protein, crude fat, pure cellulose, lignin, other carbohydrate, N, P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, Co and Ni and to reach 50% of their steady state levels of accumulation on the Sasa paniculata type grassland in Naitai Grassland in Kamishihoro are 5.07, 5.01, 5.03, 3.04, 4.61, 12.58, 2.91, 2.49, 8.11, 5.69, 12.58, 16.19, 4.93, 9.82, 13.33, 11.95, 25.29, 14.90, 9. 19, 8.42, 6.00 and 5.55 years respectively. 5. Quantities of annual cycles of C, N, P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, Co and Ni are 187.53, 2.129, 0.095, 0.776, 0.301, 0.069, 0.281, 6.1・10^<-3>, 14.8・10^<-3>, 9.5・10^<-3>, 0.95・10^<-3>, 0.23・10^<-3> and 0.46・10^<-3>g/m^2 respectively.
