Estimating forage yield by the double-sampling method
1944
Wilm, H.G. | Costello, D.F. | Klipple, G.E.
Two double-sampling methods, using line-transects and forage weight estimates, were tested to ascertain their relative efficiency in estimating the amount of forage present on experimental areas, as compared to the clipping of vegetation on sample plots. Considering field work alone, double-sampling with the line-transect method provided an increase in information of about 28% as compared with the information which could have been obtained by clipping only, during the same period of time. On the basis of time expended in both field and office, the double-sampling method provided only about 11% more information than could have been obtained by clipping alone. The use of weight estimates in double-sampling provided about 37% more information than could be obtained by straight clipping in an equivalent amount of field time. If field work and office compilation are both considered the gain in information dropped to about 14%. Under our conditions of intensive sampling both methods provided substantial economies in field time and some saving in total time expended. In other studies, however, these savings would be considerably affected by the relative amount of time consumed in field travel as compared to the time requirements of clipping and double-sampling. In large-scale extensive surveys, the clipping of all plots may prove to be at least as efficient as any short-cut method.
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