Narrow Plots Research Articles

Estimates of Cost and Optimum Plot Size and Shape for Measuring Yield and Chemical Characters in Soybeans1

SynopsisSeed yield was 6 to 28 times more variable than chemical characters (oil, protein, iodine number). Use of incomplete block designs and other considerations justified long, narrow plots. Total cost (in hours) was 39.0% for obtaining yield and 61.0% for chemical attributes. Optimum plot size, apportioning cost among characters, was 3.2 times the basic unit ( 8 × 2 feet). Yield required 33, 50 and 700 times more replication than oil, protein and iodine number for comparable precision.

A uniformity trial on groundnuts

A uniformity trial on groundnuts has been analysed and the results discussed. Plant number is less variable than yield and less sensitive to shape of plot and of block. For yield, long narrow plots are more efficient than shorter and wider plots, in all shapes and sizes of blocks and in Latin squares. The plots should not be arranged end to end along the contours, but side by side, either singly or in pairs, forming compact blocks.The regression of the plot variance of the mean yield per unit area on size of plot approximately follows a linear logarithmic relationship. A similar relationship holds for plant number. The value of the regression coefficient b′ is low and it has been shown that, as expected, there is considerable gain from the use of small blocks. The efficiencies of various confounded and incomplete block designs relative to designs in larger blocks have been determined for some particular layouts, and values for other layouts, ignoring shape of plots and of blocks, have been obtained by interpolation.The field used for this uniformity trial appears equally variable in all directions.

A Revival of General Education

T HERE is no common agreement today on what the term general education means, nor do educators agree on precisely what the objectives of a general education are. While it is impossible, then, to offer a definition of the term or a statement of these objectives that will be acceptable to all, perhaps this paper can make clear what the author thinks a general education ought to do for the student. A general education should develop the individual's capacities for living. It should stimulate and enrich his social consciousness. While it emphasizes the growth of the individual, its governing principle is the unity of human knowledge; it aims to produce not narrow specialists but wellinformed citizens who can take active roles in the affairs of their own community. Nevertheless, general education does not oppose specialization. What sensible person today would deny the value of expert training? General education tries, at the very least, to induce the student to view the world as a whole rather than as a narrow plot bounded by the limits of his particular special knowledge or skill. Ideally, all specializations should rest upon, or grow out of general culture. For example, the engineer will Drobablv be a better engineer if he knows something about the history of man, if he has some comprehension of art, if he has puzzled over philosophy and psychology. Certainly, the engineer with a developed social consciousness will be a better citizen than he would have been if his studies had all been directed toward the acquisition of professional knowledge. General education should point, though it may fall short, at the lofty mark which the poet Milton once set. I call, therefore, he said, Ca complete and generous education that which fits a man to perform justly, skillfully, and magnanimously all the offices both private and public of peace and war. General education, which strives for a unity of human knowledge, is by no means a new ideal. In fact, it is a very old one. The revival of the ideal during the past twenty years, in both theory and practice, is largely a revival of older methods. The exponents of general education today are trying to find a system of study that will accomplish what older systems evidently did accomplish; namely, give the students a common fund of information about the world in which they live and a common attitude toward what is right and wrong, what is worthy and what unworthy of right-minded citizens.

EFFICIENCY IN FIELD TRIALS OF PSEUDO-FACTORIAL AND INCOMPLETE RANDOMIZED BLOCK METHODS

Uniformity data for eight different crops were studied with the object of making comparisons of the efficiency of Incomplete and Randomized Block methods. Altogether 26 different comparisons were made.In general the Incomplete Block method gives increases in efficiency, such increases being partially correlated with soil heterogeneity. If the field is very uniform there may be a loss in efficiency but this is rather unlikely on the average field and with careful planning of the experiment. The increases in efficiency due to the use of Incomplete Block methods would appear to vary on the average from 20 to 50%. In view of the greater adaptability of these methods to irregularly shaped fields, in addition to greater efficiency, their use can be generally recommended.The relative efficiency of Incomplete and Complete Block methods was studied in relation to the size and shape of plots and blocks. The former method gives the greatest gains in efficiency when the Incomplete Blocks are nearly square and are made up of long narrow plots.

Experimental Error and the Field-Plot Technique with Potatoes (With One Diagram and One Text-figure.)

The present investigation consists of the statistical analysis of a uniformity trial with potatoes conducted by Dr Kirk. In this study the standard error in per cent. of the mean decreased slightly with the increase in the widths up to plots 5 rows wide, but any further increase in the width of the plot resulted in the higher standard error. The fertility contour map of the field is given in Fig. 1 to show graphically the effect of soil heterogeneity on the yield. The increased size of the plot resulted in the decreased efficiency in the use of the land when the entire plot was harvested; in other words, given a piece of land of certain size, it is advantageous to have a greater replication of smaller plots than a smaller number of larger plots. Four-row plots proved to be the most efficient when the border rows are discarded. The superiority of long and narrow plots over shorter and wider ones is demonstrated.With the greatest pleasure I acknowledge my indebtedness to Dr Kirk, who supplied me with the data, to Dr Fisher for his valuable suggestions and to Dr J. Wishart for useful advice and criticism.

Influence of Size and Shape of Plots on the Precision of Field Experiments with Potatoes

1. A uniformity trial with potatoes was used for investigating the effect of size and shape of plots on the precision of field experiments. Up to a certain limit the S.D. in per cent. of the mean decreases when the size of plots is increased; further increase of plot size increases the errors as a lesser part of the soil variation can be removed.2. Two-row plots show less variation than either 1 or 3-row plots. This may be explained by row competition.3. When the area to be used is fixed, smaller plots are more efficient than larger, owing to the greater number of replications in the former case. One exception occurs in the case where border rows are not harvested; here 4-row plots are more efficient than 3-row plots, owing to the fact that a larger part of the soil is included in the calculations when 4-row plots are used.4. Long and narrow plots are more efficient than shorter and wider of the same size. The only exception is again explained by row competition.5. In field experiments with potatoes fairly large plots should be used; at least 2 rows wide and preferably long and narrow strips.