A single field experiment was conducted in 1994 at Maricopa, AZ to compare a scheduled approach (based on stage of growth) versus a feedback approach (based on vegetative status) to both nitrogen (N) and mepiquat chloride (PIX™) applications on Upland cotton (Gossypium hirsutum L.). PIX feedback treatments were based upon fruit retention (FR) levels and height: node ratios (HNRs) according to established baselines. Scheduled PIX applications were made for a total of 1.0 pt./acre over two applications, with feedback PIX treatments receiving a single 0.5 pt./acre application near peak bloom (approx. 2200 heat units after planting (HUAP), 86/55 °F threshold) Scheduled applications of fertilizer N totaled 225 lbs. N/acre from four applications and feedback N treatments received a total of 135 lbs. N/acre from three 45 lb. N/acre applications. Treatments consisted of all combinations of scheduled or feedback applications of both N and PIX. The highest lint yields were from a treatment receiving feedback N and PIX and a treatment receiving scheduled N and PIX, which were not significantly differencent (P ≤ 0.05) from one another. From a practical standpoint, however, these treatments were very different in terms of the magnitude in differences of fertilizer N and PIX required to produce comparable yields.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/210296 |
| Date | 03 1900 |
| Creators | Silvertooth, J. C., Norton, E. R., Unruh, B. L. |
| Contributors | Silvertooth, Jeff |
| Publisher | College of Agriculture, University of Arizona (Tucson, AZ) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Article |
| Relation | 370099, Series P-99 |
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