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.
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.
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.