Spittlebug eggs: comparison of sampling efficiency of sample units of different sizes.
The sampling efficiency of three sample units was compared to determine spittlebug egg densities in pastures of Brachiaria decumbens Stapf. To obtain the same level of precision, the total pasture area to be examined increased by 1,5 times when size of the sample unit was increased from 75 to 150 cm2, and by 2,5 times when it was increased to 225 cim2. Using the 75 cm2 unit, the number of samples necessary for 10% 15% and 20% levels of precision were estimated to be 170,82 and 48, respectively. The distribution pattern of egg counts per 75 cm2 of the pasture, fitted the negative binomial series. A study of sampling variation within 1 ha pastures, showed that differences between bloks, or plots within blocks were significant only in about 20% instances.Nevertheless, choosing of distributed sampling sites whthin the sampling area was suggested.
| Main Authors: | , , , , |
|---|---|
| Other Authors: | |
| Format: | Artigo de periódico biblioteca |
| Language: | English eng |
| Published: |
2007-12-17
|
| Subjects: | Dourados, Mato Grosso do Sul, Pasture, Spittlebugs, Amostragem, Brachiaria Decumbens, Cigarrinha das Pastagens, Deois Flavopicta, Entomologia, Ovo, Pastagem, Zulia Entreriana, Cercopidae, Brazil, eggs, entomology, sampling, |
| Online Access: | http://www.alice.cnptia.embrapa.br/alice/handle/doc/319769 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | The sampling efficiency of three sample units was compared to determine spittlebug egg densities in pastures of Brachiaria decumbens Stapf. To obtain the same level of precision, the total pasture area to be examined increased by 1,5 times when size of the sample unit was increased from 75 to 150 cm2, and by 2,5 times when it was increased to 225 cim2. Using the 75 cm2 unit, the number of samples necessary for 10% 15% and 20% levels of precision were estimated to be 170,82 and 48, respectively. The distribution pattern of egg counts per 75 cm2 of the pasture, fitted the negative binomial series. A study of sampling variation within 1 ha pastures, showed that differences between bloks, or plots within blocks were significant only in about 20% instances.Nevertheless, choosing of distributed sampling sites whthin the sampling area was suggested. |
|---|