Stripper harvesting

Because of cost/proflt relationships, for example, harvesting methods vary with cultural practices. About 30 percent of the U. S. cotton crop is stripper-harvested. In Texas, more than 80 percent of the cotton is stripper-harvested because of crop culture, low harvesting cost, and high harvesting capacity associated with strippers. 

Harvesting by means of strippers is practiced mainly in West Texas and the adjoining areas of Oklahoma and New Mexico. This method has also gained great Importance in the Coastal Bend area of Texas. Because a stripper harvester (whether a finger stripper or a brush stripper) removes almost all vegetative material from the plant (except for the central stem and major branches), about 1100 kg of harvested material are brought to the gin to yield one 218-kg bale of lint. The lint therefore is approximately one-third of the harvested material in spindle-picked cotton and can be as little as one-fifth in stripper-harvested cotton. 

Some stripper harvesters are equipped with onboard cleaners that have cleaning effectiveness of up to 50 percent. Their cleaning effectiveness depends, however, on machine adjustment and on other factors not yet identified. In one test, big differences in cleaning performance have been shown to exist between identical harvesters operating under Identical field conditions (2. This study is continuing and should lead to improved stripper-mounted cleaner performance. 

Reductions in bur and stick content of stripper-harvested cotton before actual ginning are important for two reasons. 

Seed-cotton loss in overhead cleaning equipment can range from 0.2 percent upward (28) but should not be over 1.0 percent. The amount of overhead cleaning machinery needed depends on the trash content of incoming seed cotton. Stripper-harvested cotton with over 30 percent trash can benefit from three extractor stages in addition to the two cylinder stages normally used. 

Once the plant is ready, the cotton is mechanically harvested with either a spindle picker or cotton stripper. The spindle picker selectively harvests seed cotton from open boUs. The unopened boUs are left on the plant and can be picked at a later date. The spindle picker uses a rotating tapered barbed spindle to remove the cotton from the bur (seed case). The seed cotton is wrapped around the spindle, pulled from the bur, removed from the spindle with a mbber doffer, and then transferred to a basket. 

Historically cotton bolls have been harvested by hand. More recently, however, the development of machine harvesters has reduced production costs. For efficient use of both types of pickers (the spindle type with rotating spindles that picks the cotton only from open bolls, and the stripper type which strips... 

FIGURE 1.4 (a) Mechanical harvesting by means of a cotton picker, (b) Mechanical harvesting by means of a cotton stripper. (Courtesy of the National Cotton Council of America, Memphis, TN.)... 

Mechanically harvested cotton, either with cotton picker machines (cotton burr remains attached to the stalk) or with stripper machines (cotton burr is removed along with the seed cotton), can contain more trash and other irregularities than hand-harvested cotton. However, according to Cotton contamination surveys by the International Textile Manufactures Federation (ITMF), the most contaminated cottons originate from some of the countries where cotton is hand-picked, whereas some of the cleanest can be sourced in the USA where cotton is machine harvested [34]. Most of the mechanically harvested cotton is harvested with cotton pickers ( 75% in the United States and all in Australia). 

Fig. 24.2 Harvesting of hamstring tendon graft. The semitendinosus tendon was identified fi-om the surface of pes anserinus tissue. Then, the semitendinosus tendon was isolated from the underneath of the gracilis tendon and harvested with tendon stripper left knee)...

The sciatic nerve may be injured when harvesting the medial hamstring using a tendon stripper. Injury to the sciatic nerve manifests drop foot and sciatic nerve numbness symptoms including extensive sensory disturbance. Attention has to be paid to the direction of entry of the tendon stripper. In patients with small physique, consideration has to be given to the fact that the hamstring runs near the sciatic nerve [11]. 

Strippers are efficient and can harvest up to 99% of the cotton from the plant. They are nonselective and remove not only the seed cotton but also the cracked and unopened bolls, the burs, and other foreign matter. The extra foreign matter requires additional cleaning at the gin. 

Hand picking is advantageous compared to machine picking, as only fibers from completely mature capsules are being collected. Usually, this cotton contains fewer plant contaminants. For automated picking, two kinds of harvest machines are used the stripper and the spindle picker. 

For an automated harvest using the stripper, the cotton plants need to be artificially defoliated, whereas this is not necessary using the spindle picker. One capsule contains about 4 g of seeded cotton, resulting in a final amount of 1.5 g of fibers after ginning. The nonflber portion is larger with the stripper method than with the spindle-picker method. 

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