GPS landforming is the reshaping of a fields topography to predesigned 3D surfaces using high-accuracy GPS to control the blade height of the earth-moving machine. It is typically done to improve surface drainage and water infiltration uniformity.
Davco Optisurface, the company that developed the 3D landform design software OptiSurface Designer, has seen strong adoption as the concept catches on. The software has been used to design more than 400,000 acres, according to Arkansas-based global sales manager Preston Marthey.
WM-Form. Trimble launched a GPS landforming software program in February. WM-Form enables growers and contractors to turn their fields into optimal surfaces, even in areas that could not be leveled before, Trimble said.
“With more farmable land that is optimized for water management and more uniform production, growers can experience increased yield,” said David Fitzpatrick, Water Solutions business area director for Trimble’s Agriculture Division.
Trimble’s product is designed to work with its WM-Topo survey system and Trimble FieldLevel II system. WM-Form has surface design tools and flexible parameters so growers and earthworks contractors can use it to repair underperforming areas and extend the amount of productive farmable land. It can reduce the volume and cost of earthworks and minimize disturbance to valuable topsoil. Growers can optimize water distribution and drainage, reduce erosion and flooding by effectively directing waterflow, and create more uniform crop production that can lead to increased yield.
Growers can analyze topographic data in WM-Form to identify surface problems limiting yield potential and create a design that optimizes their field’s surface. The software also provides reports for volume, area and constraints, providing an accurate quote on the total cost of the project.
Horizon. Topcon’s Horizon software is an icon-based, user-definable system that presents a choice of views for each function you perform. It runs on all three of Topcon’s X family of precision agriculture consoles. With Horizon, growers can set autosteering patterns, control application rates, monitor operations, and map every pass — and a new feature allows for water management.
“Water conservation…is designed to provide the ability to perform land forming while also offering GNSS auto steering of the tractor,” said Neal Toso of Topcon Positioning. Using the Topcon X30 and AGI-4, water conservation and land forming users can level fields while auto-steering to maximize efficiency and reduce the amount of material moved, he said.
“With the X30 console, using Horizon software, connected to Topcon MC-R3 blade control, it is easy to take the output from Topcon AGForm 3D design software to produce accurate modeling and land forming. This allows proper drainage to occur, resulting in a healthy, productive crop,” said Toso. “Together, these Topcon products are designed to provide a turnkey approach to superior landforming operations.”
In Costa Rica, Jose Maria Aguero, CEO-director general of Agricultura Cientifica S.A., now uses Horizon. Aguero first employed laser leveling in the late 1970s. “We started noticing that rice and other crops produced less in areas with deep cuts from laser leveling because we had cut the more fertile topsoil off,” Aguero said. “But it was the only tool we had, so we kept doing it.”
Then Aguero discovered Topcon’s GPS land forming products. “Sugar cane crops are expanding dramatically in our area, and the operators don’t use irrigation. Water management is needed to improve drainage because in the rainy season it is too wet, which affects crop development. The only way the cane companies can get sugar cane into a new growing area is with GPS and 3D landforming,” he said.
“GPS with 3D landforming only moves 250 to 300 cubic meters per hectare,” Aguero said. Compared to laser leveling, “That is more than a 90 percent reduction in cost. And, moving less soil keeps more of the fertile top layer in place to promote fertility.”
Landforming Lessons
Surface drainage and irrigation problems can be solved with GPS landforming at low cost, agricultural engineer Graeme Cox says. This is proven with many crops and farming styles, irrigated and non-irrigated.
Cox has learned the following about GPS landforming, based on his experience around the world.
Water is king. Eighty percent of yield variability and profit loss is due to too much, or too little, water. Yield maps show this. “Focus on optimizing water management first,” Cox said.
Ponding kills profits. If water is standing in fields 24 hours after rainfall or irrigation, it is killing profits. “Expect eight percent per day yield loss plus nitrogen loss, increasing pest and disease, delaying planting, spraying and harvesting.”
Subsurface tile drainage is good, but expensive. “Tiling typically has a lower return on investment than GPS landforming and does not work well on heavy soils or those with limited elevation relief,” Cox said.
Ditching is good. “But,” he adds, “it can be a pain if ditches take out valuable crop area or restrict machinery access.”
Lasers are dead. Lasers only work in a straight plane. GPS allows farmers to follow curved topography with curved design surfaces.
Earthworks and topsoil movement can be reduced up to 80 percent with landforming designs and GPS machine control compared to other methods, Cox claims.
