Jaime Vivo, who has been working on his family’s Los Macachines farm in San José, Uruguay, for more than 20 years, reports that he has obtained the maximum precision that PPP can achieve: three to four centimetres. Between the family farm and clients’ rented fields, he manages about 3,000 hectares (7,410 acres) of soy, wheat, barley, corn and sorghum.
He has practiced precision agriculture for a total of about four years, having previously used a GNSS receiver from Müller-Elektronik GmbH for spraying. The accuracy of the Müller system, combined with e-Dif differential corrections, was about 25 centimetres. About a year ago, Vivo worked with Carlos Cabral, a product support specialist with Ag Leader Brazil, to have the Ag Leader GPS 6500 system with TerraStar installed on a Case 9370 tractor.
Cabral points out that two issues affect system accuracy: overall correction signal accuracy and the tractor’s steering system, which compensates for field topography. Because Vivo’s fields are on flat terrain, Cabral says that topography was not really a factor.
Last year, Vivo watched the NovAtel TerraStar-C system in action while Cabral planted wheat rows spaced 20 centimetres apart. To check accuracy, Cabral measured the distance from one pass to the next. Based on about a dozen measurements over the course of three passes, Cabral determined that the accuracy was within three centimetres almost invariably, four centimetres at the most. Such precision was adequate for planting rows based on 20-centimetre centres.
“The operator works more comfortably and relaxed and, at the same time, I can rely on the operator and on the results,” Vivo says.