Harvest chemical aids

These data do not show the presence of crop protection or harvest aid chemicals. 

Wesley and Wall (19) collected and analyzed airborne dust samples collected from three areas within five Mississippi gins in 1975. The general composition of their samples are summarized in Table IV. These data show the dust to be about 30 percent cellulosic, the remainder being soil and other materials. The quantitative elemental analysis of their samples is detailed in Table V. Although the percentages are different, the constituents in these samples of gin dust are very similar to those listed by Brown (18) in whole plant parts. None of the data presented have identified residues from insecticides or harvest aid chemicals. This may be because they were not specifically sought. 

As pointed out earlier, all U.S. cotton in commercial production is now harvested by machines. The application of harvest-aid chemicals to cause the plants to shed their leaves (defoliation) or to kill and dry the plant (desiccation) are common practices in many areas. Chlorates and organic phosphates are popular defoliant materials and arsenic acid is commonly used as a desiccant. 

A defohant causes the leaves to drop from plants without killing the plants. A desiccant speeds up the dryiug of plant leaves, stems, or vines. Desiccants and defohants are often called "harvest-aid" chemicals. They usually are used to make harvestiug of a crop easier or to advance the time of harvest. They are often used ou cottou, soybeans, tomatoes, and potatoes. 

Uses Agric. surfactant for herbicides and harvest aid chemicals Atplus 522 [Croda Inc]... 

We all know of the old practice of "pickin cotton" - harvesting cotton bolls by hand. In general, this practice has been replaced by machine harvesters. Since introduction of the harvest machine, use of chemical aids has become common-place. Cotton leaves are defoliated by chemical harvest aids on more than 75% of the cotton acreage in the U.S. - representing more than 7 million acres of cotton. 

Chemical harvest aids are presently used on more than 75% of the cotton acreage in the U.S.. The amount of foliage may be reduced either by the use of defoliants or the use of desiccants. Defoliants induce leaf fall and must be applied one to two weeks before harvest so that the abscission process may be complete. Desiccants cause the foliage to lose water and sometimes the leaves and stems are killed so rapidly by desiccants that an abscission layer has insufficient time to develop and the drying leaves remain attached to the plant. Desiccants usually require one to three days to act before harvest can be started. The obvious advantage of desiccants over defoliants is that they may be applied at a later date, thus gaining additional time during which the leaves continue to function and to contribute to see the fiber quality. Hundreds of chemicals have been evaluated as defoliants and desiccants. Only a few are in commercial use. 

Another problem or consideration that may interfere with some aspects of allelopathy (especially in field experiments) has arisen over the past fifty years with the introduction and use of a multitude of xenobiotic compounds as insecticides, fungicides, plant growth regulators, harvest aids, and herbicides. A variety of such compounds have been and continue to be used on a world-wide scale. Some of these chemicals and/or their transformation products are persistent in soils and water. Other such chemicals are routinely applied at various times during a year. These xenobiotics may interfere or interact with naturally occurring allelochemics and thus alter or even mask certain natural allelochemical effects. Researchers will have a more difficult time to find natural areas that do not contain xenobiotic... 

Chemical aids to harvest and fruit abscission agents are reviewed and discussed in relation to structure, mode of action, and predictability of response. Also, an attempt is made to assess the physiological basis for different responses among fruits of differing physiological age and among various organs on the same plant. 

The majority of data on the physiology of abscission were obtained using leaves, and principal concepts evolved from these observations. Dijfferences among fruit, leaf, or other organ abscission are indicated as applicable to the discussion. Because of the vast number of articles published on abscission, neither time nor space will allow this to be an all-inclusive review, but hopefully the selected references allow an assessment of present knowledge of fruit abscission and chemical aids to harvest. Several excellent reviews are available on various phases of abscission (2-6) and alhed areas (7, 8, 9). 

Soybeans [Glycine max (L.) Merr.] is a native crop of China and one of the oldest oilseed crops in the world. Soybeans are an important source of dietary protein and oil for humans and animals and can aid in reducing chronic diseases. They are also used for soyfoods, and the oil has use as a renewable biofuel. Whether soybeans are crushed for soybean meal and crude oil or used directly for food, industrial chemicals, or fuel, the quality of soybeans will never be higher than that at harvest. From harvest onward, quality at best can only be maintained. In fact, major effort is made solely to slow the normal rate of deterioration so that soybeans can provide an ample year s supply with some carryover and sufficient seed for future propagation. 

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