Standing Crop and Production in an Undisturbed Shrubsteppe Community in Eastern Washington

摘要

Standing crop and production were investigated in an relatively undisturbed (ungrazed) shrubsteppe plant community in southeastern Washington. Total standing crop was 1600g dry weight per m exp 2 with 460g aboveground and 1140g belowground. Grass crowns, litter and standing dead herbaceous plants amounted to 127g and sagebrush shrubs 270g. Twenty-five percent of the belowground biomass was in the upper decimeter of soil profile and 41% in the first two decimeters. Over a 4-year period, aboveground production averaged 70g per m exp 2 per y, about 10g of this amount was produced by sagebrush shrubs. About 10 g of herbaceous shoot biomass was produced during the autumn and winter months and 60 g in April, May and early June. The average rate of herbaceous shoot biomass production was 0.66 g per m exp 2 per day over a 75-day period in the spring. Year to year herbaceous shoot biomass production ranged between 50 and 69 g per m exp 2 at peaks yields. This is a relatively small range as compared to growing season precipitation totals which ranged between 8.1 and 22.6 centimeters. Shoot productivity in this shrubsteppe community was at the low end of the ranges cited in the literature for other kinds of semi-arid steppe communities in the western United States. 19 references, 3 figures, 6 tables. (ERA citation 10:011028)