Sampling Date

Due to the constraints of time and labor, it is unusual to conduct biomass sampling at a site more frequently than once a year. However, total standing crop fluctuates during the year due to physical decomposition, utilization by domestic and wild herbivores, and consumption by insects. Furthermore, species composition and species biomass also vary within the year according to the contrasting growth requirements of warm season and cool season plants, making it difficult to obtain a realistic determination of productivity from a single sampling period.

Therefore, the time of sampling for a yearly measurement must consider the biomass property to sample, and growth dynamics of key species at the site.

References and Further Reading

(Note: pdf files require Adobe Acrobat (free) to view)

Biondini, M.E., Lauenroth, W.K., and O.E. Sala. 1991. Correcting estimates of net primary production: are we overestimating plant production in rangelands. Journal of Range Management 44:194-198. (pdf)

Bonham, C.D. 1989. Measurements of terrestrial vegetation. John Wiley Sons, New York, NY. pp 216-217.

Holechek, J.L., Pieper, R.D., and C.H. Herbel. 1995. Range management principles and practices. Prentice Hall, Englewood Cliffs, NJ. 2nd ed. pp 135-136.

Kelly, J.M., Van Dyne, G.M., and W.F. Harris. 1974. Comparison of three methods of assessing grassland productivity and biomass dynamics. American Midland Naturalist 92:357-369.

Malone, C.R. 1968. Determination of peak standing crop biomass of herbaceous shoots by the harvest method. American Midland Naturalist 79:429-435.

Pieper, R.D., Dwyer, D.D., and R.C. Banner. 1974. Primary production of blue grama grassland in southcentral New Mexico under two soil nitrogen levels. Southwestern Naturalist 20:293-302.

Willms, W.D., Adams, B.W., and J.F. Dormaar. 1996. Seasonal changes of herbage biomass on the fescue prairie. Journal of Range Management 49:100-104.

URL: http://cals.arizona.edu/OALS/agnic/knowledge/chapter5/samplingdate.html
Last Revised: 29 December 1997