Mar 10, 2017

Agronomy & physiology WCRC Agro-Physio-north-america WCRC1
Abstract                                                                         Back to Table of contents

We introduced the University of California Plant Mapping Program to growers in the Imperial Valley for the first time for the 1993 cotton season.  Because the equations used in the program were derived from data collected in the San Joaquin Valley for Acala varieties, many potential users questioned the validity of applying the program to Upland cotton fields growing in the low desert (i.e. Imperial Valley).  They wanted to know if the program could make accurate predictions for varieties other than Acalas in an environment other than the San Joaquin.  Could they trust their management decisions to a program developed from another region's database?

In order to address these concerns and to help convince the growers of the value of plant mapping, we collected both in-season and final plant map data from thirty Imperial Valley cotton fields during the 1993 season. Height to node ratios vs. age (as number of nodes) for Imperial Valley plants followed the same pattern, but were slightly lower than, the curve for San Joaquin fields.  Some fields came closer to the line representing the San Joaquin database than others.  Nodes above white flower values from Imperial Valley fields followed the same relationship to days after first flower as the San Joaquin fields.  Growers actively making management decisions with the aid of the programs picked over 2242 kg lint/ha.  Those not guiding their decisions brought in less than 1121 kg lint/ha.  We determined two factors critical to good cotton production in the low desert:  timing of early season irrigation and early retention of first position fruits.  We conclude that the UC Plant Mapping Programs served as useful guides in an area quite different from the San Joaquin.

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