HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Roel, A. Articles by Plant, R. E. Search for Related Content PubMed Articles by Roel, A. Articles by Plant, R. E. Agricola Articles by Roel, A. Articles by Plant, R. E. Related Collections Rice Site-Specific Analysis

Factors Underlying Yield Variability in Two California Rice Fields

^a Graduate Group in Ecology, Univ. of California, Davis, CA 95616, USA
^b Dep. of Agron. and Range Sci. and Dep. of Biol. and Agric. Eng., Univ. of California, Davis, CA 95616, USA
^c Present address: Instituto Nacional de Investigaciones Agropecuarias, Treinta y Tres, Uruguay

View larger version (11K): [in a new window]   Fig. 1. Soil sampling locations in (a) Field 1 and (b) Field 2.

View larger version (84K): [in a new window]   Fig. 2. Cluster sets of Field 1. The number code identifies the value of k, which is the number of clusters, followed by the identification number of the set. For example, Set 2-1 is the first set of two clusters (k = 2). The numbers in the legend identify the gray-scale key of the elements belonging to each cluster.

View larger version (68K): [in a new window]   Fig. 3. Large-scale yield trends obtained by Roel and Plant (2004) for Field 1 using median polish. Redrawn from Roel and Plant (2004).

View larger version (52K): [in a new window]   Fig. 4. Large-scale yield trends obtained by Roel and Plant (2004) for Field 2 using median polish. Redrawn form Roel and Plant (2004).

View larger version (32K): [in a new window]   Fig. 5. Cluster means for the clusters of Fig. 2. Each plot shows the sequence of means of standardized yield values, obtained by subtracting the mean and dividing by the standard deviation, of the corresponding cluster for each of the 4 yr of data. To conserve space, the axes are not labeled. The abscissa is the year, and the ordinate is the standardized cluster mean.

View larger version (83K): [in a new window]   Fig. 6. Cluster sets of Field 2. Coding and legend keys are the same as those of Fig. 2.

View larger version (27K): [in a new window]   Fig. 7. Cluster means for the clusters of Fig. 6. Each plot shows the sequence of means of standardized yield values, obtained by subtracting the mean and dividing by the standard deviation, of the corresponding cluster for each of the 3 yr of data for this field. To conserve space, the axes are not labeled. The abscissa is the year, and the ordinate is the standardized cluster mean.

View larger version (17K): [in a new window]   Fig. 8. Classification tree obtained for clusters of Field 1 at k = 4. The value of N in each box indicates the number of elements comprising that node of the classification tree. For example, the value N = 18 in the uppermost box indicates that there are 18 elements in which normalized difference vegetation index (NDVI)-2001 > 0.425 and soil penetration resistance (SP) > 0.38. The numbers on the second line in each box indicate the percentages of each cluster contained in that classification and regression trees (CART) node. For example, the node corresponding to the uppermost box is comprised of 28% Cluster 1, 33% Cluster 2, etc. Boxes with rounded corners indicate terminal nodes with a majority of members from one cluster, in which case the node is identified with that cluster. For example, the node corresponding to NDVI-2001 > 0.425 and SP 0.38 MPa is identified as corresponding to Cluster 3. This is indicated by the numeral to the right of the box.

View larger version (14K): [in a new window]   Fig. 9. Classification tree obtained for Field 2 at k = 3. The interpretation is the same as that of Fig. 8.