​Defoliants Harvest-aid Chemicals: Cost Effective Technology to Facilitate Synchronized Maturity for Mechanical Harvesting in Cotton: A Review

In the recent years, increasing labour cost and shortage of labour being the major constraints to follow manual harvesting in cotton in staggered manner. Further, it is very expensive and farmers would like to increasingly opt for mechanical harvesting. In this context, it is suggested that research should focus to reduce cost of cultivation substantially by promoting the use of synchronized maturity in cotton and use of defoliants to encourage mechanical harvesting. In agriculture, defoliants are used to eliminate the leaves of a crop plant so that they do not interfere with the harvesting by machinery. Early harvesting with good boll opening can also be achieved by use of defoliants. The use of defoliants also reduces the trash content in picked cotton which will also help in improving the quality of cotton. There is a need to identify suitable defoliant with suitable dose and time of application so as to facilitate mechanical harvesting in rainfed cotton. Some of the successful defoliants for uniform boll bursting and higher yield of cotton such as rthrel, rthepon, mepiquat chloride (MC), sodium salt and DU (Dropp Ultra) are the hormonal defoliants and TDZ thidiazuron butifos, merphos, tribufos and tribufate are the herbicidal defoliants. The best combination of thidiazuron + diuron (DCMU), pyraflufen ethyl, thidiazuron + diuroncellular isozyme, Ethephon + AMADS, ethephon + cyclanilide ethephon + tribufos Mepiquat chloride (MC) + cyclanilide may be recommended to facilitate mechanical harvesting in cotton.

4 Agrochemical Residues, Product Quality, and Safety of Beef Fed Cotton Ginning and Other Byproduct Feeds

Most commodity crops undergo milling, husking, ginning or other processing procedures before use as human food or fiber. Byproduct nutrient density varies with the type of grain or oil seed processed and use typically varies with nutrient needs of specific production situations. Drought or high grain prices may increase the use of byproducts; regionally available, low-cost ingredients such as cotton ginning byproduct may be used extensively by beef producers to replace forage. Doubt associated with the use of such byproducts is not typically related to nutritional value but with uncertainties about the presence of residual pesticides, herbicides, or harvest-aid chemicals. Potential chemical residues in consumer products and the concomitant financial and reputational losses borne by the industry provide an impetus for concern. Negative experiences with contaminated Australian beef established a long-lived suspicion of “cotton trash” that continues to impact the industry today. The purpose of this review is to discuss sources, amounts, and risks of chemical residues associated with byproduct feeds used in the southern United States with cotton ginning byproducts as a major focus. The use patterns of specific crop protection and harvest-aid chemicals will be discussed in context with chemical tolerances established by the U.S. EPA. In addition, U.S. pesticide monitoring programs in beef will be discussed. Although data describing the transmission of chemical residues from byproduct feeds into beef products are limited, the available data suggest some best practices could be adopted to mitigate concerns and minimize possible agrochemical residue contamination of beef.

Impact of harvest-aid defoliants on yield and economics of high density cotton

A field experiment was conducted to study the effect of chemical defoliation on growth parameters, seed cotton yield and economics of cotton under high density planting during kharif, 2016. Defoliation with Etherel @ 2000 ppm at 60 boll opening percentage resulted in higher number of picked bolls plant-1 and boll opening percentage and seed cotton yield (2359 kg ha-1). At harvest, significantly highest drymatter accumulation was recorded with Urea @ 15% (T6) (22692 kg ha-1). Dropp Ultra 560 SC (Thidiazuron 360 + Diuron 180) @ 200 ml/ha recorded significantly higher leaf defoliation (99.7 %) and was superior over other defoliants tried. Application of defoliants i.e., Dropp Ultra and Etherel at 60 BOP resulted in reduction of crop duration by 20 days.