This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Ultra Narrow Row (UNR) and conventional (CNV) cotton production systems were compared with respect to agronomic practices, yield, fiber quality, and production costs in experiments conducted in 1999 and 2000 in central Arizona. Cotton rows were 10 and 40 inches apart in the UNR and CNV systems, respectively. In 1999, the average lint yield in the UNR system, 1334 lb/A, was significantly greater than the 1213 lb/A yield of the CNV system. Similar results were obtained in 2000 with yields of 1472 and 1439 lb/A for the UNR and CNV systems, respectively. Fiber grades of both systems were comparable with most bales receiving a grade of 21 in 1999. The average bale grades in 2000 were 11 and 21 in the UNR and CNV systems, respectively. The quality of the fiber produced in both systems was also comparable with staple and strength measurements meeting base standards in both years. However, there was a consistent difference between the UNR and CNV systems in both years with respect to micronaire. Micronaire averaged 4.5 and 4.0 in the UNR system in 1999 and 2000, respectively, and 5.0 and 4.9 in the CNV system in 1999 and 2000, respectively. Variable growing costs were $607 and $446 for the UNR system in 1999 and 2000, respectively, and $660 and $519 for the CNV system in 1999 and 2000, respectively. Harvest and post-harvest variable costs were $234 and $209 in the UNR system in 1999 and 2000, respectively, and $217 and $224 in the CNV system in 1999 and 2000, respectively. The economic data indicated that the UNR system reduced production costs and increased profitability without sacrificing lint yield or quality. However, these experiments also indicated that many production challenges such as planting and obtaining adequate plant populations, managing plant height control, and weed control need further study.

A field experiment was conducted in 2000 to evaluate narrow (30") and ultra narrow (10") row spacing cotton production systems. The study was conducted at a commercial farm located near Buckeye, AZ. The experimental design was a randomized complete block with three replications. The treatments included 10" row spacings that were harvested with a finger stripper, 30" row spacings harvested with a brush stripper, and 30" row spacings harvested with a spindle picker. Plant growth and development was not affected by row spacing throughout the growing season. No significant difference was observed for lint yield however, gin turnout was slightly lower for stripper harvested treatments. Fiber quality measurements were similar for both row spacing with the exception of fiber micronaire which was lower in stripper harvested treatments. Bark was a major problem with stripper harvested treatments with at least 92% of bales receiving a discount compared with 36% of spindle harvested bales.

The continuing investigation in ultra-narrow row cotton production has not produced a definitive answer to whether this practice would be economically feasible in this area. Results of this season showed that planting two seed rows on a bed can produce yields in excess of those yields produced with a single seed row, where the plant populations are comparable. This configuration can be harvested with a conventional spindle picker. Plant mapping data and HVI data are shown for all treatments in this study.

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