Unevenness of the soil surface has a significant impact on the germination, stand & yield of crops. Farmers also recognize this and therefore devote considerable time and resources in leveling their fields properly. However, traditional methods of leveling land are cumbersome, time consuming as well as expensive. As per studies significant (20-25%) amount of irrigation water is lost during its application at the farm due to poor farm designing and unevenness of the fields. This problem is more pronounced in the case of Sugar cane fields. Fields that are not level have uneven crop stands, increased weed burden and uneven maturing of crops. All these factors lead to reduced yield & poor grain quality.

BENEFITS OF LAND LEVELLING:

. Optimization of water use efficiency

. Better crop establishment

. Reduction in irrigation time

. Less effort in crop management

. Laser leveled land

. Less weed problems

. Uniformity in crop maturity

. Time efficiency in completion of task

. Easy land preparation

. Less water requirement for land preparation

1. YIELD : Research has shown a large increase in rice yield due to proper field leveling.

2. WEED CONTROL: Improved water coverage from better land leveling reduces weeds by up to 40%. This reduction in weeds results in less time for crop weeding.

3. FARM OPERATION: Laser leveling makes possible the use of larger fields. Larger fields increase the farming area and improve operational efficiency. This increase in farming area gives the farmer the option to reduce operating time by 10% to 15%.

4. SEEDING PRACTISES: Laser leveled larger fields reduce the time taken for planting, for transplanting and for direct seeding.

5. EFFICIENT WATER MANAGEMENT: An unleveled field means extra water storage in fields to accomplish pudding in paddy field. Moreover land leveling effectively terraces fields allowing water in the higher fields to be used in the lower fields for land preparation, plant establishment & irrigation.

6. ECONOMICS: The initial cost of laser land leveling is high but if the appropriate plowing techniques are used, re-leveling the whole field should not be necessary for at least eight to ten years. Measurements taken in fields in the second and third year after leveling have shown very little variation in surface topography. Other benefits are :

• Being able to direct seed.

• Plow the field on time.

• Harvest evenly ripened crop.

• Reduced weeding cost.

To sum up the benefits of laser land leveling:

• More level and smooth soil surface.

• Reduction in time and water required to irrigate the field.

• More uniform moisture environment for crops.

• Reduced consumption of seeds, fertilizers, chemicals and fuel.

• Improved field traffic ability (for subsequent operations).

HOW LASER LEVELLER WORKS:

The laser-controlled system requires a laser transmitter, a laser receiver, an electrical control panel and a twin hydraulic control valve.

The laser transmitter transmits a laser beam, which is intercepted by the laser receiver mounted on the leveling bucket. The control panel mounted on the tractor interprets the signal from the receiver and opens or closes the hydraulic control valve, which will raise or lower the bucket.

1. TRACTOR: It is preferable to have 4-wheel drive tractor instead of 2 wheel drive tractor. Higher the horse-power faster the operations. The size of the tractor can vary from 30-500 HP depending upon time constraints and field sizes.

2. PLOUGHING: The fields will require ploughing depending upon the soil that must be cut.

3. DRAG BUCKET: The leveling bucket can be either 3-point linkage mounted or pulled by the tractor's drawbar. Pull type systems are preferred as it is easier to connect the tractor's hydraulic system to an external hydraulic ram.

4. LASER TRSNSMITTER: The laser transmitter is mounted on a tripod, which allows the laser beam to sweep above the tractor unobstructed. With the plane of light above the field, several tractors can work from one common transmitter.



5. LASER RECEIVER: The laser receiver is an omni-directional receiver that detects the position of the laser reference plane and transmits these signals to the control box. The receiver mounts on a manual must attached to the drag bucket.



6. CONTROL PANEL: The control box accepts and processes signals from the machine-mounted receiver. It displays these signals to indicate the drag bucket's position relative to the finished grade. When the control box is set to automatic, it provides electrical output for driving the hydraulic valve. The control box is mounted on the tractor within easy reach of the operator. The three control box switches are on/ off. Auto / Manual, and Manual Raise/ Lower ( which allows the operator to manually raise or lower the drag bucket ).



HYDRAULIC CONTROL SYSTEM:

The hydraulic system of the tractor is used to supply oil to raise and lower the leveling bucket. The oil supplied by the tractor's hydraulic pump is normally delivered at 2000-3000 psi pressure. As the hydraulic pump is a positive displacement pump and always pumping more oil than required, a pressure relief valve is needed in the system to return the excess oil to the tractor reservoir. If the relief valve is not large enough or malfunctions damage can be caused to the tractor's hydraulic pump.

The solenoid control valve controls the low of oil to the hydraulic ram, which raises and lowers the bucket. Te desired rate at which the bucket raises and lowers will depend on the operating speed. The faster the ground speed the faster the bucket will need to adjust. The rate at which the bucket will raise and lower is dependent on the amount of oil supplied to the delivery line.



1. HOW TO LASER-LEVEL LAND:

Laser leveling requires soil to be shifted from the high points of the field to the low points in the most cost effective way. In most situations fields will need to be plowed and a topographic survey undertaken before leveling commences.

Step-1 : Plowing The Field

Plow the field preferably from the centre of the field outwards. It is preferable to plow the field hen the soil is moist because if the soil is plowed dry a significant increase in tractor power is required and large clod sizes may result. If the soil is very dry a one-way disc or moldboard may be required. Rotary tillers, disc harrows or cultivators are ideal for second workings. All surface residues need to be cut up or removed to aid soil flow from the bucket.

Step-2 : Conducting A Topographic Survey

Once the field is plowed, you should conduct a topographic survey to record the high and low spots in the field. From the surveyed readings you can then establish the mean height of the field by taking the sum of all the readings and dividing by the number of readings taken. Then using a field diagram and the mean height of the field you can determine a strategy to effectively move soil from the high to low areas.



Step-3 : Levelling The Field

• The laser-controlled bucket should be positioned at a point that represents the mean height of the field.

• The cutting blade should be set slightly above ground level (1-2 cm).

• The tractor should then be driven in a circular direction from the high areas to the lower areas in the field.

• To maximize working efficiency, as soon as the bucket is near filled with soil the operator should turn and drive towards the lower area. Similarly as soon as the bucket is near empty the tractor should be turned and driven back to the higher areas.

• When the whole field has been covered in this circular manner, the tractor and bucket should then do a final leveling pass in long runs from the high end of the field to the lower end.

•The field should then be re-surveyed to make sure that the desired level of precision has been attained.

• In wet areas where there is a poor traction or a chance of bogging the tractor, care needs to be taken to fill the wet areas in a circular motion.

• If the fields are properly plowed and leveling undertaken in the areas of soil settlement in the second year, the fields should not require further major leveling works for at least 8 yrs.

System configuration consists of

1. Scraper Bucket :

Frame	: 50 x 10 mm Angle. 125 x 65 mm    Channel box.
Center Support	: 125 x 65 mm Channel.
Sheet	: 10 mm.
Blade	: 100 x 10 mm.
Draw Bar	: 75 x 40 mm Channel Box.
Hydraulic Cylinder	: 2 Ton ( capacity ).
Height	: 600 mm.
Width	: 2 mtr.
Tyre Set	: 65x8 mm box with tyre. (with tapper roller bearings ).

2. Machine Control System ( Receiver ) : To be mounted on Tractor

1. Laser Sensor (receiver) with carry case to be mounted on a mast directly above bucket : 1 pc

2. Control Panel with keys and LED display for manual and automatic control of Hydraulics of Tractor : 1 pc.

3. Cable connecting Laser Sensor to Control Panel : 1 pc.

4. Cable connecting 12 V Battery to Control Panel : 1 pc.

5. Cable connecting Auto panel to Valves of tractor for Hydraulic control : 1 pc.

3. Laser Transmitter: To be mounted on Tripod on Land

1.Rugby Series Laser transmitter ( Rugby 50/Rugby 100/ Rugby 100LR) with carrying case. A). Specifications of the Rugby 50(Agri.) Operating range : 800 meters diameter Self-leveling accuracy : ± 2.6 mm at 30 m Self-leveling range : ± 5°. Rotating head speed : 10 rps Battery life : 60 hours (alkaline), 35 hours (NiMH or 12 V) Laser diode : 780 nm Laser classification : Class I Dimensions : (158 x 163 x 166 mm)hwd Weight with batteries : 1.85 kg Environmental : Waterproof, IP55 Warranty : One-year knockdown

B).Specifications of the Rugby 100(Agri.)

Operating range	: 800 meters diameter
Self-leveling accuracy	: ± 2.6 mm at 30 m
Self-leveling range	: ± 5°.
Rotating head speed	: 5 and 10 rps
Manual grade	: Up to 10%
Battery life	: 60 hours (alkaline), 35 hours (NiMH or 12 V)
Laser diode	: 635 nm
Laser classification	: Class II
Dimensions	: 7.8 x 9.8 x 6.9" (200 x 250 x 175 mm)
Weight with batteries	: 6.5 lbs. (2.95 kg)
Environmental	: Waterproof, IPX6
Warranty	: One-year knockdown

C).Specifications of the Rugby 100LR(Agri.)

Operating range	: 1500 meters diameter
Self-leveling accuracy	: ± 1.5 mm at 30 m
Self-leveling range	: ± 5°.
Rotating head speed	: 5 and 10 rps
Manual grade	: Up to 10%
Battery life	: 60 hours (alkaline), 35 hours (NiMH or 12 V)
Laser diode	: 780 nm
Laser classification	: Class I
Dimensions	: 7.8 x 9.8 x 6.9" (200 x 250 x 175 mm)
Weight with batteries	: 5.5 lbs. (2.5 kg)
Environmental	: Waterproof, IPX6
Warranty	: One-year knockdown