Manoj Kumar
Scientist, ICAR-Central Institute of Agricultural Engineering, 
NabiBagh, Berasia Road, Bhopal - 462038 (Madhya Pradesh) INDIA

Indian agriculture is practiced in hilly, plain, plateau andcostal reasons, which includes enormous diversity in the land. Despite agricultural mechanization, Indian agriculture is still dependent on physical labour. The farming operations which are not mechanized required timely and reduced cost of operation. Some Indian agriculture fields are infested with a number of small pebbles and stones in various regionsdue to theirvarying topography. These small pebbles and stones create obstacles in farming activities like field preparation, sowing/planting, intercultural reapingand harvesting (Ex. Soybean, black gram, etc.) operations. Due to these reasons,the farming operations in stone-infested agricultural fields require higher costs as well as time.

The farm machinery for different farm operations like land preparation, sowing, fertilizer application, spraying and harvesting are available, but the stone picking from agricultural fields is done manuallyin India. Now some manufacturers/innovators are making tractor rear-mounted stone pickers for picking the pebbles and stones from the agricultural fields. The use of this machine will increase the timeliness of agricultural operations, minimizelabour requirements and increase the efficiency of different farming operations. Farmers are not or less aware of this tractor-operated stone picker machine, so in this article, the details of stone picking machines in India are discussed.

In India, a tractor rear-mounted stone picker machine is used for this work. The stone picker in India can be divided into two types i.e. (i) tractor-mounted stone picker machine with a bucket and (ii) tractor-mounted stone picker conveyor type. The details of the stone picker are discussed below:

Tractor-mounted stone picker machine with a bucket
The machine consists of an arrangement for hitching the stone picker machine to the tractor, a digger, a stone separator unit, a stone collector tank/bucket-cum-stone unloading unit and a pair of wheel (Fig.1). The work of different machine parts are:

Digger: This is a blade that is fixed in front of the digger unit for loosening and lifting of the soil and stones which enters inside the machine due to the forward operation of the machine.

Stone separator: Stone separator is made of mild steel rods and it is mounted on a moving/oscillating chain/belt which is rotating with the help of a gearbox driven by PTO power. The stone separator convey the soil, stones and pebbles received from the digger unit to the rear end of the machine. In this operation, the stone and pebbles are separated from the soil and the soil falls down in the field.

Stone tank and unloaded: A stone tank/bucket made of mild steel is mounted at the rear end of the machine for the collection of the stones. The stone bucket unit has a set of hydraulic cylinder which is used for unloading of stones in the field or in a tractor trolley. The approximate capacity of the stone tank/bucket is 800-900 kg.

The capacity of the machine was approximately 2-4 acres/day. The cost of a machine is in the range of 2-3 lakhs. This machine with some modification can be used for digging different tuber crops. The tractor power requirement for operation of this machine is 40 horse power or more.

Tractor-mounted stone picker conveyor type
The tractor-mounted stone picker conveyor type is also mounted at the rear of the tractor. It consists of an arrangement for hitching the stone picker machine to the tractor,a digger blade, stone separator and conveyor belt and a pair of the wheel. The work of different machine parts are: The digger and stone separator of this machine also work similar as previous machine. Whereas a inclined conveyor belt with lugs is used in this machine which convey the stones received from stone separator to a higher height, so that a horizontal rubber conveyor belt which is mounted at perpendicular direction of machine travel receives the stones and deliver it in a tractor trolley which is moving parallel to the stone picker machine.

The different benefits of use of stone picker machine are reduction in manual labour requirement, increase in the easiness of the farm operation, less damage in the agricultural equipment, less power requirement for farm operation and saving of time. The farmer can use the machine and reap benefits of removing of the stone and pebbles from their agricultural fields.