Introduction:

Uneven soil surface has a major impact on the germination, stand, and yield of crops due to inhomogeneous water distribution and soil moisture. Therefore, land levelling is a precursor to good agronomic, soil, and crop management practices.
Traditionally farmers level their fields using animal drawn (Fig: 1.a) or tractor-drawn levelers (Fig: 1.b). These levelers are implements consisting of a blade acting as a small bucket for shifting the soil from higher to the low-lying positions. It is seen that even the best leveled fields using traditional land leveling practices are not precisely leveled (Fig. 2) and this leads to uneven distribution of irrigation water.
The common practices of irrigation in intensively cultivated irrigated areas are flood basin and check basin irrigation systems. These practices on traditionally leveled or unlevelled lands lead to water logging conditions in low-lying areas and soil water deficit at higher spots.

The advanced method to level or grade the field is to use laser-guided leveling equipment. Laser land leveling is leveling the field within certain degree of desired slope using a guided laser beam throughout the field.

Components of Laser Leveling System:

A laser-controlled land leveling system consists of the following five major components:
(i) Drag Scrapper/bucket:
The drag bucket can be either 3-point linkage mounted on or pulled by a tractor. This system is preferred as it is easier to connect the tractor’s hydraulic system to an external hydraulic by the 3-point-linkage system.

(ii) Laser transmitter:
The laser transmitter mounts on a tripod, which allows the laser beam to sweep above the field.

(iii) Laser receiver:
The Moba LS3000 laser receiver is a multi-directional receiver that detects the position of the laser reference plane and transmits this signal to the control box.

(iv) Control box:
The Laser Matic control box accepts and processes signals from the machine mounted receiver. It displays these signals to indicate the drag buckets position relative to the finished grade.

(v) Hydraulic system:
The hydraulic system of the tractor is used to supply oil to raise and lower the leveling bucket.

Working mechanism of Laser Leveler:

Fig: Showing different components of Laser Levelling System

The system includes a laser-transmitting unit that emits an infrared beam of light that can travel up to 500m in a perfectly straight line. The second part of the laser system is a receiver that senses the infrared beam of light and converts it to an electrical signal. The electrical signal is directed by a control box to activate an electric hydraulic valve. Several times a second, this hydraulic valve raises and lowers the blade of a grader to keep it following the infrared beam. Laser leveling of a field is accomplished with a dual slope laser that automatically controls the blade of the land leveler to precisely grade the surface to eliminate all undulations tending to hold water. Laser transmitters create a reference plane over the work area by rotating the laser beam 360 degrees. The receiving system detects the beam and automatically guides the machine to maintain proper grade. The laser can be level or sloped in two directions. This is all accomplished automatically without the operator touching the hydraulic controls.

Benefits of laser land leveling over conventional land leveling:
• Reduction in time and water for irrigation
• Uniform distribution of water
• Less water consumption in land preparation
• Precise level and smoother soil surface
• Uniform moisture environment for crops
• Lesser weeds in the field
• Good germination and growth of crop
• Uniformity in crop maturity
• Reduced seed rate, fertilizers, chemicals and fuel requirements

Benefits of precise land leveling:
• Saves irrigation water >35 %
• Reduced weed in the field
• Increase in field areas about 3.5 %
• Reduce farm operating time by 10 %
• Assist top soil management
• Saves labor costs
• Saves fuel/electricity used in irrigation
• Increase productivity up to 25 %

Conclusion:

Laser leveling of agricultural land is a conservation technology. It has the potential to change the way food is produced by enhancing resource-use efficiency of critical inputs without any disturbing and harmful effects on the productive resilience of the ecosystem.
In spite of several direct and indirect benefits derived from laser land leveling technology, it is yet to become a popular farming practice in the developing and the underdeveloped countries. For accelerating its popularization and large-scale adoption, it requires a number of well-considered and synchronized research, extension, participatory, economic initiatives keeping in view the long-term sustainability of production systems.
Popularization of this technology among farmers in a participatory mode on a comprehensive scale, therefore, needs appropriately focused attention on priority basis along with requisite support from researchers and planners. The change in vision of future agriculture in relation to food and nutritional security, environmental safety and globalization of markets demands improving resource-use efficiency considerably to reach the desired growth levels in food production and agricultural productivity. Laser leveling is evidently one of the ways by which we can address these issues to a great extent.