Influence of Small Plot Size and Shape on Range Herbage Production Estimates

Ecology ◽  
1963 ◽  
Vol 44 (4) ◽  
pp. 746-759 ◽  
Author(s):  
George M. Van Dyne ◽  
W. G. Vogel ◽  
H. G. Fisser
Keyword(s):  
Size And Shape ◽  
Plot Size ◽  
Small Plot

Field Plot Technique Studies with Flue‐Cured Tobacco. I. Optimum Plot Size and Shape 1

1963 ◽  
Vol 55 (2) ◽  
pp. 197-199 ◽  
Author(s):  
Julian W. Crews ◽  
Guy L. Jones ◽  
D. D. Mason
Keyword(s):  
Field Plot ◽  
Size And Shape ◽  
Plot Size ◽  
Field Plot Technique

Problems in the use of microplots for assessing the fate of urea applied to flooded rice

1988 ◽  
Vol 39 (3) ◽  
pp. 351 ◽  
Author(s):  
ACF Trevitt ◽  
JR Freney ◽  
JR Simpson ◽  
WA Muirhead
Keyword(s):  
Solar Radiation ◽  
Preliminary Analysis ◽  
Ammonia Volatilization ◽  
Urea Hydrolysis ◽  
Incident Solar Radiation ◽  
Size And Shape ◽  
Flooded Rice ◽  
Ph Values ◽  
Plot Size ◽  
Heat Penetration

The effects of differences in size of microplot and type of enclosure on the floodwater parameters determining ammonia volatilization were studied. The results show that the use of enclosures can retard urea hydrolysis, suppress the maximum daytime pH values (an effect which is cumulative over a number of days), and significantly reduce the potential for ammonia volatilization. These effects are the consequence of lowered light (and heat) penetration in the enclosed area due to shading of the floodwater by the enclosure walls. The magnitude of these effects varies with plot size and shape, and the material used for construction of the plot wall. A preliminary analysis suggests that, if errors due to shading are acceptable when 90% or more of the incident solar radiation always penetrates to the enclosed floodwater, then square plots with opaque walls must be at least 1.2 m along a side and cylindrical plots must be at least 1.2 m in diameter when wall height is 0.1 m above the floodwater.

THE PRECISION OF FIELD EXPERIMENTS WITH VEGETABLE CROPS AS INFLUENCED BY PLOT AND BLOCK SIZE AND SHAPE.: II. CANNING PEAS

1960 ◽  
Vol 40 (2) ◽  
pp. 396-404
Author(s):  
I. L. Nonnecke
Keyword(s):  
Field Experiments ◽  
Block Size ◽  
Yield Variability ◽  
Vegetable Crops ◽  
Optimum Size ◽  
Size And Shape ◽  
Plot Size ◽  
Effect On Yield ◽  
Block Sizes ◽  
Uniform Reduction

In 1957, vine and shelled pea weights of canning peas from an irrigated uniformity trial were recorded to determine the effect on yield variability of varying plot and block sizes and shapes. The most uniform reduction in variation occurred in block shapes of one plot long and six plots wide with each increase in plot length. These results agree with those of other workers, that long, narrow blocks are more efficient than square blocks. The optimum plot size was found to be 5 feet long and 10 feet wide. Considerably more shelled peas were required for processing than could be obtained from the optimum size of plot for yield.

Optimizing plot size and shape for field experiments on terraces

1997 ◽  
Vol 33 (01) ◽  
pp. 51-64 ◽  
Author(s):  
R. Poultney ◽  
J. Riley ◽  
R. Webster
Keyword(s):  
Experimental Error ◽  
Field Experiments ◽  
Residual Variance ◽  
Size And Shape ◽  
Plot Size ◽  
Upper Limit ◽  
Plot Analysis ◽  
Residual Variances

Two methods, namely combined plot analysis and integration of variograms, have been applied to investigate and compare plot-to-plot yields of intercropped millet (mean yield of about 1.9 t ha−1) and maize (mean yield 4.25 t ha−1) on terraces in Nepal. Combining plots diminishing the residual variance of millet from 0.52 (t/ha)2 of the original 1 m×1 m units to 0.08 (t/ha)2 for 4 m×4 m plots, the largest for which reliable estimates could be derived. The residual variance of maize declined from 4.91 (t/ha)2 of the original units to 0.61 (t/ha)2 for 4 m×4 m plots. Orientation was immaterial. The variogram for millet was isotropic and bounded with a range of approximately 4 m. Within-plot variance calculated from the variogram increased, and experimental error decreased, as the size of plots increased to this value, beyond which there was little gain. The variogram for maize was unbounded, and so gave no ‘natural' upper limit for plot size, that is, over the range studied, up to 6 m×6 m. It was also anisotropic with larger gradient in the direction from front to back of the terrace than along the contour. The reduction in residual variance was greatest for narrow plots elongated in this direction. Formulae are provided from which to calculate from the variogram approximate residual variances for experiments of given area and size, shape, and orientation of plots. Its application gave similar results to those from the combined plot analysis. Overall, the results from the two methods were consistent.

scholarly journals Effects of gap area and shape on recolonization by grassland plants with differing reproductive strategies

1997 ◽  
Vol 75 (2) ◽  
pp. 352-361 ◽  
Author(s):  
Peter M. Kotanen
Keyword(s):  
Plant Communities ◽  
Clonal Growth ◽  
Reproductive Strategies ◽  
Dispersal Ability ◽  
Gap Size ◽  
Grassland Vegetation ◽  
Size And Shape ◽  
Plot Size ◽  
Grassland Plants ◽  
Annual Grasses

Species with poor dispersal ability initially should be slower to colonize larger or rounder gaps than smaller or less circular gaps. Conversely, dispersive and seed-banking species should be less sensitive than poor dispersers to gap size and shape, and less confined near the edges of a gap. I tested these ideas with a 3-year experiment in which I monitored the revegetation of gaps in grassland vegetation. Initially, species reproducing largely by clonal growth (bulbs and perennial graminoids) were the most sensitive to gap size and (to a lesser extent) shape, reaching their greatest abundances in small and (or) rectangular openings. Species relying on seed dispersal (annual grasses) also tended to do best in smaller plots, but were less concentrated near the edges of the plots. Species relying on seed dormancy (dicots and J uncus bufonius) were least sensitive to plot size, shape, and distance from an edge. In subsequent years, these patterns often were obscured or reversed, reflecting continuing seed immigration and environmental and competitive conditions within gaps. These results indicate that species respond to gap size and shape in ways consistent with their reproductive biologies, and suggest that the importance of the dimensions of gaps may vary among plant communities. Key words: disturbance, gap shape, gap size, grasslands, revegetation, succession.

scholarly journals PLOT SIZE AND SHAPE FOR FIELD TRIALS WITH FORAGE CACTUS PEAR

2021 ◽  
Vol 39 (2) ◽  
pp. 334-349
Author(s):  
Bruno Vinícius Castro GUIMARÃES ◽  
Sérgio Luiz Rodrigues DONATO ◽  
Ignacio ASPIAZÚ ◽  
Alcinei Místico AZEVEDO ◽  
Abner José de CARVALHO
Keyword(s):  
Soil Heterogeneity ◽  
Field Trials ◽  
Production Cycle ◽  
Index Number ◽  
Cactus Pear ◽  
Area Index ◽  
Size And Shape ◽  
Plot Size ◽  
Relative Information ◽  
Federal Institute

This study aimed to determine the size and shape of experimental plots that provide maximum precision using relative information method. This trial was conducted at the Federal Institute of Bahia. Plant height, cladode length, cladode width, cladode thickness, cladode area, cladode area index, number of cladodes, cladode total area and yield were measured in the third production cycle, 930 days after planting. The plants, defined as basic units, were arranged in 39 plot sizes so that the crop would fill the whole experimental area. Then, plot shapes with higher relative information and equal plot size in basic units were selected. The experimental plot with eight basic units in size ensures higher efficiency in the experimental evaluation. This combination between size and shape, besides meeting all evaluation requirements of the characteristics normally assessed in studies with forage cactus pear, has the maximum control of soil heterogeneity, thereby decreasing experimental error and significantly increasing precision.

Sample size and sampling intensity in relation to the precision of small-plot herbage sward trials

1968 ◽  
Vol 70 (1) ◽  
pp. 19-27 ◽  
Author(s):  
C. A. Foster ◽  
C. E. Wright
Keyword(s):  
Sample Size ◽  
Dry Matter ◽  
Matter Content ◽  
Dry Matter Content ◽  
Dry Matter Yield ◽  
Botanical Composition ◽  
Plot Size ◽  
Sampling Intensity ◽  
Length Measurements ◽  
Small Plot

SummeryThree sampling experiments were conducted to examine the effect of sample size and sampling intensity on the precision of dry-matter content and botanical composition estimates of perennial rye-grass-white clover herbage. One of these experiments examined the between-sample variability of these attributes and of dry-matter yield in relation to other sources of experimental error in a small-plot sward trial. The sample sizes examined were 800 g, 400 g, 200 g, 100 g, 50 g and 25 g green weight. In general the accuracy of dry-matter content and botanical composition estimates decreased with decreasing sample size. The between-sample variabilities of 25 g and 50g samples were high in relation to their between-plot variabilities. Single 100 g samples provided reasonably good estimates of these attributes and of dry-matter yield, but single 200 g samples provided a more satisfactory margin for error. Samples larger than 200 g appeared to be unnecessary. When weight-for-weight comparisons of single and duplicate samples were made there appeared to be little advantage in duplicate sampling. A theoretical examination of measurement inaccuracies inherent in the techniques used in small-plot sward trialssuggested that variation in plot length measurements in particular may make an undesirable contribution to the variability of such trials. A procedure for the conduct of small-plot trials is recommended. It is concluded that, where plot size and replication are limited, further improvement in the precision of such trials will not be readily attainable.

Sign in / Sign up

Export Citation Format

Share Document