Developing a precision farming system in South Africa

Koot Smit grows 1,000 hectares of crops on his farm, ‘E J P Smit Boerdery’ in the Vryheid district in South Africa, with two thirds maize and one third soya beans on a rotation.

Autosteer accuracy. -Photo credit: Koot Smit 

Mr Smit is collaborating with agronomist Stephen Pennells of Agrisol and is in agreement with Stephen that the concept of precision farming is a long term process and results cannot be expected immediately. So far, he is confident that his system is improving yields and lowering input costs.

Long term process starts with 3 steps

The first step was to map all the fields using GPS mapping. These maps are placed on the Agrisol online system, where each client has his own login details so that his particular information is available at all times.

At the request of the farmer, soil samples are taken by a dedicated team employed by Agrisol. There is a choice of various grid specifications from 0.25ha to 4ha and 3 different types of tests are conducted.

1. The first test is the normal soil analysis, to indicate the levels of the various elements in the soil.
2. The second tests nutrient availability. This is very important since it gives a more complete indication of the amount of each element that is available to the plant. Sometimes the amount of an element indicated may seem to be sufficient according to the normal test, but in fact may be completely unavailable to the plant due to various other soil factors. In this case, corrections can be made by bringing up the levels of other elements that influence the availability. Another option is the use of specific foliar feeds.
3. The third test is soil health analysis. This indicates the amount of micro bacterial activity in the soil. These soil organisms all produce certain amounts of nitrogen and phosphate, which is available for the plants to use. Research by Agrisol has shown that considerable savings in the cost of fertiliser can be made by improving the health of the soil.

Advice on fertilisers

Using the results of the analysis, the agronomist recommends what fertilisers should be applied and the foliar feeds necessary for the growing crop. This is an advisory service and the decisions as to which products to use are up to the farmer. The system generates prescription maps for lime application as well as phosphates, potassium and trace elements like boron, zinc, manganese, iron and copper. These maps give the whole picture.

Lime is applied to correct acidity, using an Agrispread lime spreader with a variable rate system, controlled though the John Deere tractor’s precision ag technology.  Autosteer was proved to be highly beneficial in the extensive fields.

Cultivation with the ‘Rolmoer’

Cultivation relies heavily on the ‘Rolmoer’, a large diameter roller with cutting blades that chop the crop residue to manageable lengths. The residue is then incorporated with an implement that has ‘Vibroflex’ tines mounted on a frame, locally manufactured by Arlington Steelworks, who also builds a Rolmoer.

Chisel ploughs are used in preference to mouldboards. This system has proven to be successful in the sandy lands, which are prone to wind erosion, if sufficient cover is not left on the surface.

Agrisol app

The John Deere planter is equipped with variable rate individual row drive and this facility is being introduced into the system, in order to control fertiliser costs. The Vicon fertiliser spreader also has variable rate application and the Jacto sprayer has variable rate and section control, operated by the JD-link system.

A crop monitoring system has been introduced this season with an app linked to the Agrisol on-line system to make the maps easily accessible. The app shows NDVI (Normalised Difference Vegetation Index) images of the field to allow identification of any problems such as insect pests, crop diseases or nutrient deficiencies. Leaf samples are also taken to enable corrective procedures to be applied timeously if required.

At the end of each season the Agrisol app generates a report of the results to enable planning for the following season. The whole system is showing good results and it enables Mr Smit to make effective decisions in time, to avoid running into trouble.