(source:VP  UDYOG)

Crop Growing and Harvesting

1. Plant:
At first the seeds are planted and the plants begin to grow and develop, they must be protected from insects, diseases and weeds.
2. Flower:
After flowering, the cotton fibers (lint) develop in the boll in three periods.
2-1.The first the thin primary wall is developed with a large vacuole (0-27 days).
2-2. During the second period (15-55 days), the protoplast shrinks (circumferentially) progressively while, at the inside of the primary wall, a mass of almost pure cellulose is deposited as a secondary wall.
2-3. By the time of boll maturation, the third period, the secondary wall fills the major part of the cell volume, leaving the lumen, the small central cavity containing the cytoplasm and the vacuole.

As the boll opens, quick desiccation occurs and the tubular cells collapse longitudinally and assume a ribbon-like form with twists called convolutions. Prior to harvesting, the plants are defoliated, thus reducing large amounts of foliage on the cotton plant that might interfere with mechanical harvesting.

Machine pickers harvest cotton from open bolls and leave unopened bolls and empty bolls on the plant. This is accomplished by revolving spindles that pluck the fiber out of the boll. Machine strippers strip the entire plant of opened and unopened bolls. The fiber removed from the plant also contains the cotton seeds and is referred to as seed cotton. After harvesting, the seed cotton is transported to the ginning factories.

Ginning
The process of separating cotton fibers from the seeds is called Ginning. The cotton gin dries and cleans (remove plant parts and field trash) from the seed cotton, separate the fiber from the seed, further clean the fibers and places the fiber into an acceptable package, while preserving the quality of the fiber.
     
      Bales Formation

After the ginning process, the output fiber is compressed by hydraulic machines into bales of 165-170 kg. At this stage, the fiber is referred to as Raw Cotton.


Variety (India Standard)

Micro

2.5 Span Length (mm)

Bengal Deshi (GATP, GAMP)

6.8 - 8.0

16 - 18

F – 414

3.5 – 4.2

24 – 26

H - 4

3.4 – 4.2

27 - 29

H - 6

3.3 – 3.9

26 – 28

J – 34

3.8 – 4.6

23 – 25

Shankar 4

3.3 - 4.2

28 – 30

Shankar 6

3.4 - 4.0

27 – 30

Cotton waste is short fiber resulting from the processing of raw cotton. The qualities of cotton waste are :

Comber Waste.
Soft Waste.
Unwillowed Dropping
Hard waste
Flat Strips
Oily Cotton

The typical applications of this material are coarse spinning, security paper, use in the bedding industry, etc.

Short Fibers (known as linters) that were not removed by ginning remain on these cottonseeds.
At the Oil mill the linters are removed from the seeds by delinting machines.

The seeds can be run through a delinting machine once, in which case the linters produced are known as Mill Run Linters.

First-cuts consist of longer, more resilient fibers and are used in a number of nonwoven products.

Second-cuts are made up of short fibers and are used to produce high grade bond paper and as a source of cellulose in the chemical industry.

3rd-cuts...

After removal of the linters, the remainder of the cottonseed is converted into food for people, feed for livestock, fertilizer and mulch for plants.