Leaf Pubescence and Defoliation Strategy Influence on Cotton Defoliation and Fiber Quality

Byrd, Seth A.; Collins, Guy; Edmisten, Keith L.; Roberts, Phillip M.; Snider, John L.; Spivey, Todd A.; Whitaker, Jared R.; Porter, Wesley; Culpepper, A. Stanley

doi:10.56454/hxyt5212

Cited by 10 publications

(2 citation statements)

References 14 publications

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“…The defoliation timing, strategy, and leaf pubescence characteristics can impact the efficacy of defoliation and the fiber quality parameters [37,38]. There were several studies on cotton fiber quality assessment [39][40][41][42]; however, no information is available on the effects of defoliant dosage with the application of cotton defoliation with side spraying covering the whole canopy of the plant (i.e., bottom, middle, and upper).…”

Section: Fiber Quality Analysis By Hvimentioning

confidence: 99%

Effect of Controlled Defoliant Application on Cotton Fiber Quality

et al. 2023

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Cotton (Gossypium hirsutum L.) is an important industrial crop. It is a perennial crop and has indeterminate growth habit, however, in most parts of the United States, it is grown as an annual crop with the application of growth regulators. Defoliation is a major production practice influencing harvester efficiency, fiber trash content, cotton yield, and fiber quality. Currently, defoliant application is done by using a conventional boom sprayer and aerial spraying in which both systems spray chemicals horizontally downwards from the top of the canopy, which causes minimal chemical to reach at bottom canopy. However, for successful defoliation, each leaf must receive the defoliant as chemicals do not move within the plant. Thus, a new autonomous ground sprayer was developed using robotics and pulse width modulation, which can be run in between two rows covering the whole canopy of the plant. Field research was conducted to study the effect of three duty cycles (20%,40%, and 60%) on cotton fiber quality using autonomous spraying system. The result indicated that the defoliants could be applied safely at either of the three duty cycles without compromising most of the fiber quality parameters except for nep/gm, length (Ln), L (5%), SFC, trash content in field 1 and micronaire, nep size, length (Ln), L (5%), SFC, and fiber fineness in field 2 which were significant. However, application of 20% duty cycle will significantly reduce the chemical use therefore, 20% duty cycle could be a good choice for the autonomous cotton defoliation. The development of autonomous spraying technology would encourage the development of new sprayer industries and the unmanned ground vehicle industries, together with the need for the global development of an agricultural system with broad market prospects and brings about huge economic, social, and ecological benefits.

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Section: Fiber Quality Analysis By Hvimentioning

confidence: 99%

Effect of Controlled Defoliant Application on Cotton Fiber Quality

et al. 2023

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“…The translocation of systemic herbicides may be the main mechanism that nullifies the effect of the droplet size and lower leaf coverage . The above studies on insecticides, fungicides, and herbicides have shown that the deposition effect and behavior of pesticide droplets have a significant impact on drug efficacy. − …”

Section: Introductionmentioning

confidence: 99%

The Relationship between Droplet Density and the Defoliation Effect of Cotton Harvest Aids

Duan,

Fang,

Dou

et al. 2024

ACS Omega

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Spraying harvesting aids is an important step before the mechanical harvesting of cotton. To clarify the direct relationship between the droplet density and the defoliation effect of cotton harvest aid solutions, we evaluated the relationship between the droplet density and the defoliation effect. The determination method and evaluation standard of the number of droplets required per square centimeter to achieve 50% leaves defoliation (DN 50 ) of the harvest aid solution were further explored. The results revealed a linear relationship between the droplet density and the cotton defoliation rate when the spraying volume was 22.5 L/ha and the harvest aid dosage was 1/2 and 2/3 of the recommended dosage. When the harvest aid dosage was 5/6 and 1 times the recommended dosage, the relationship between the droplet density and the defoliation rate of cotton was logarithmic. The DN 50 of the low-concentration harvest aid solution (450 L/ha) was significantly higher than that of the high-concentration solution (22.5 L/ ha). The addition of spray adjuvant Beidatong significantly reduced the DN 50 of cotton harvest aids. The field experiment showed that the droplet density increased with the increase of the spraying volume sprayed by unmanned aerial vehicles. There was a positive correlation between the spraying volume and the defoliation effect after changes in the cotton harvest aid dosage. When the dosage of Mianhai (MH) was 5/6 of the recommended dosage, the defoliation effect at the spraying volumes of 22.5, 27.0, and 30.0 L/ha reached the peak values at 71.54, 78.56, and 83.23%, respectively. This study proposed the concept of DN 50 and its determination method. The fitting equations between the droplet density and defoliation effect and between the harvest aid concentration and defoliation effect were established to provide a theoretical basis for the scientific spraying of cotton harvest aid solutions.

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