Cotton Growth and Production as Affected by Moisture, Nitrogen, and Plant Spacing on the Yuma Mesa

Abstract

Acala 44 cotton was grown near Yuma, Ariz. on irrigated Superstition loamy sand having a steep productivity gradient from one end of the field to the other. Effects of soil moisture, N rate, and plant spacing, each at 3 levels in a factorial experiment, were determined for vegetative growth, fruiting, N uptake, yields, and ginning and fiber characteristics. Yields were increased substantially by N, and significantly, but less so by moisture and spacing. The spacing effect was limited to the second of 2 pickings. Considering the 4 direct factors which determine cotton yields (total flowers, percent boll‐set, boll size, and percent lint) fertilizer affected 2 and spacing 4 of these factors. The precision of the experiment did not permit a decision as to how moisture increased yields since none of the 4 factors were affected significantly. Cotton growth and production were unsatisfactory where substantial cuts were made in leveling the field before planting. The range of yields among individual plots varied almost 800% with a maximum of 2.51 bales and a mean of 1.28 bales of lint per acre. In spite of the large productivity gradient and resultant variations in growth and yield, relative response to a given treatment was remarkably consistent.

Boll Shedding and Growth of the Cotton Plant in Relation to Irrigation Frequency1

“…Hamilton et a!. (7) working under conditions of limited plant growth found no differences in flowering or boll set in cotton irrigated 41, 21 or 12 times.…”

Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel I. The Coastal Plain Region

“…Harris and Hawkins (1942) and Hamilton et al (1956) found in Arizona that early irrigations, which induced good vegetative growth before fruiting, also increased cotton yields. However, Thornton (1961) found that cotton needed a good supply of moisture during the boll setting period, until about three-fourths of the bolls were mature, whereas moderate drought in the early growing period did little harm.…”

Direct and Residual Effects of Two Mixtures of Nitrogen and Phosphorus Upon the Growth of Acala Cotton in the Pecos Valley1

“…The optimum is a finite quan• tity when the regression of yield of lint on the amount of N applied is curvilinear. Linear relationships have been reported ( 6,11) . The optimum amount of P required by cotton is affected by the accompanying application of N (2,4,5).…”