Comparison of sampling methods and sample sizes for the assessment of pre- harvest rodent damage in wheat (Triticum aestivum) fields

Abstract

Pre-harvest rodent damage (per cent cut tillers) Was assessed using three sampling methods, namely parallel sampling, transect sampling and random sampling. Each sample of two sample sizes, 10 and 20 per field in four fields of wheat (Triticum aestivam L. emend. Fiori & Paol.) crop at Ludhiana during 1999-2000 was tried. The rodent damage in the fields selected was found to be both aggregated as well as sporadic. The results revealed non-significant differences in rodent damage with three sampling methods and two sample sizes. This may be due to the reason that most of the sampling units, ie 52.5 ±14.79, 45.0 ±22.91 and 75.0 ±22.91 % (n=10) and 70.0 ±11.18, 72.5 ±11.46 and 67.5 ±10.31 % (n=20) in parallel, trunsect and random sampling respectively had no damage, thus increasing the value of standard deviation over the mean value. Per cent aggregated damage tmore than 10% in a sampling unit) for the sample sizes was reflected more by random sampling method thus indicating the suitability
and feasibility of different sampling methods depending upon the pattern and extent of rodent damage.