Stripping of pods is performed manually by the small farmers (Figure 7) or by the strippers. There are two type of groundnut strippers, the drum type and comb type.

 Figure 7: The women-farmers and hired female labours are doing manual stripping of groundnut pods. In the background bullocks are also enjoying the freshly harvested crop.

The description of the drum type stripper developed at Zonal Research Centre, Tamil Nadu Agricultural University, Coimbator. Drum type strippers consist of a hollow drum formed by two metal discs at the ends, connected on the periphery of 5 1/2 inch M.S. rods inserted inside and covered by thick and soft rubber tubes. This drum is mounted on pedestal bearings and is free to rotate. It is fixed on a framework at a conventional height so that the operator can stand and beat the root portion of handful of plants over the rubber-covered roads of the revolving drum.

To avoid scattering of pods, a hood frame is also provided. The roof as well as the three sides, i.e. other than the operator's side is covered with a canvas or gunny bag. One man can carry the unit. A comb type groundnut stripper is used for stripping the pods from the wet groundnut vines. This has been developed at Zonal Research Centre, Tamil Nadu Agricultural University, Coimbator. The unit consists of a square frame of four vertical-standards with a strip of expanded metal fixed on to each of its side in the form of a comb. The stripping of the pod is accomplished by drawing a handful of vines across the comb with slight force. The structure facilitates use by four persons simultaneously.

Stripping of pods from the vines is done by several methods. In bunch type the plants are stacked in heaps with the pod end exposed. Please see Figure 8 and 9.

 Figure 8: Comb type groundnut stripper. Source: NDDB

 Figure 9: Drum type groundnut stripper. Source: NDDB

The pegs become brittle within a week and pods are stripped by hand. In some areas in India the pods are first lifted out of the soil, dried in the field and then the pod ends of the plant are knocked against a crossbar to dislodge the pods. In this process some pods b../img/ch21/ecome damaged. This method of stripping is cheaper. A simple comb-type stripper and peddle-operated stripper are available and can be used for bunch types of groundnut.

In the case of runner types, the plants are first allowed to dry, then are beaten with flails and the pods are separated from the beaten mass by winnowing. The pods left over on the vines are handpicked. This method of stripping is not preferred as it is considered to reduce the fodder value of the vines. The Central Institute of Agricultural Engineering (ICAR) Bhopal, India has developed a CIAE Groundnut power stripper to strip the pods from green vines both runner and Spanish types, however, it need more testing and demonstrations to be implemented at the farmers level (Figure 10).

 Figure 10: Groundnut stripper for stripping green vines developed by CIAE (ICAR), Bhopal.

Threshing operations also very both within and among the developing countries. It varies from the age-old procedure of using sticks and racks to the modern power threshers. In India the smallholder and marginal farmers do manual threshing using sticks and rakes. Variations also exist in stripping pods from the plant. After harvest bunch type plants are stacked in heaps with the pod-end exposed. After the crop has remained in this state for a week or so the pegs become brittle and the pods are plucked from the plants with labour. This operation is comparatively difficult as the attachment of peg to pod is stronger in bunch type than the runner types, but drying the plants for a few days facilitates this operation.

Sometimes the stripping of the pods is also performed side by side with the harvest when the crop area is small and labourers are available. In this case, the pods are dried immediately after stripping. In Pollachi (Tamil Nadu, India) the usual practice is to separate pods by beating the pod-end of the plants against a rough stone or a thick iron rod. This process damages a small percentage of the pods. Following this method the proportion of the damaged pods is not appreciable and is a considerable labour saving.

A pedal operated thresher based on the Japanese Paddy thresher tried in Tamil Nadu has proved useful for the bunch type in which the pods are clustered together at one end; however in spreading types pod are found all along the branches and have to be plucked individually. The attachment of peg to pod in runner types is also weaker. In this case none of the above methods would work satisfactorily in case of runner type, thus it becomes a laborious process. In most of the groundnut-growing areas in India for example the states of Andhra Pradesh, Maharastra and Gujarat, the harvested plants are allowed to dry well on the threshing floor, the dried mass is beaten with flails. After making sure that the pods have been detached from the plants, pods are separated from the beaten mass by winnowing.

Threshing involves quite distinct operations including separating the pods from the vine, sorting the pods from the haulms and winnowing the chaff from the pods. In some parts of India. small farmers employ manual threshing. After drying the groundnut plants in sunlight in the field for 4 to 5 days they are collected at one place. Threshing is done manually by a wooden comb type structure with a long handle (Figure 11). Earlier in Gujarat farmers used to follow this procedure but now it has become an obsolete technology, mainly due to the availability of power operated opener or thresher in local markets.

Groundnut pods are properly picked either manually or by the thresher after sufficient drying. In Gujarat, the farmers, local artesian and traders have designed and developed efficient threshers. At adequate moisture content of groundnut plant, pods are harvested directly in a power thresher. Oil engines or electrical motor operated groundnut threshers can be used for higher land holdings. The capacity of thethresher ranges between 2 000 to 2 500 kg of groundnut pods day^-1 and requires at least two people for operation. The first separation of groundnuts from all other material occurs during threshing and or combining. The threshers used in India are quite efficient and require skill to adjust it prior to threshing, otherwise losses like incomplete separation and breakage of pods may occur.

 Figure 11:An old method of threshing groundnut pods.

The best threshing is obtained with minimum loses at pod moisture content between 18 and 20 percent. Groundnut threshers are generally designed as axial flow where the plant moves in a direction parallel to the beater axis. The pods are separated from the remainder of the plant in the threshing chamber so that the latter is expelled at the other end of the thresher. The impurities fall onto the sieve, where the leaves and light material are removed by air from the blower. The clean pods than fall through the sieve and are discharged through the pod outlet. The clearance between the bar and the screen is too small to admit the pods with the shell. The machine can be trickle-fed automatically or fed by handfuls. The JYOTI Ltd, Vadhodhra, (India) has developed a decorticator, which performs simultaneously decorticating and cleaning operations. The blower separates the hull and clean kernels are discharged through the grain outlet. Ball/bush bearings with oil cups are standard fittings. The capacity is 10 to 20 kg h^-1. The thresher requires 10 hp and is operated by 3 to 4 people (Figure 12).

 Figure 12:Threshing operations in the field, groundnut opener being operated with the help of tractor engine and another with a diesel engine.

 Figure 13:Winnowing and cleaning operations are being performed by the farm family.