Precision Farming : A User’s View

Vilhelm F Erichsen PrEng
Farmer from Middelburg
Tel. no. 013 245 1753
Fax 013 245 1599
Cell: 082 388 3380


Precision farming has made significant changes in agriculture since its induction some eight years ago. Quite a number of farmers have taken to these practises, but there is still a great deal to be learnt about precision farming and its uses. As time progresses, the methodologies will change and new technology will dictate the accuracy within the practise. It is only possible to measure production and profitability if one can measure point-specific data and do analyses for that point.

The purpose of the paper would firstly be to advise participants to be cautious; secondly, request formal training institutions to be equipped to train the generations to come for this highly intelligent issue; and finally to prompt engineers for innovative direction in precision agriculture toward designing applications for extended use in farming.

The issues being addressed are issues that have come all the way and have in some way or another been solved or are gradually being solved.


Remote sensing has been with us for many a mile. The applications have increased exponentially and with the ease that we can acquire the colour images, one can only but say that the application for agriculture is excellent. With the ease of adjusting the image to a real world position, the application for agriculture accelerates.
Remote sensing has been with us for many a mile. The applications have increased exponentially and with the ease that we can acquire the colour images, one can only but say that the application for agriculture is excellent. With the ease of adjusting the image to a real world position, the application for agriculture accelerates.
The concerns have been the available technology and expertise to analytically interpret and prescribe the images for farmers and users of remote sensing.
Red areas are high indexes of vegetation and correspond well with the green areas of yield mapping. Brown and yellow areas correspond well with lower yields of the yield maps.
Predictions of crop potential for any farmer is of utmost importance. Marketing of the crop in times prior to harvesting is crucial to obtain significantly higher prices for the product being produced.
With remote sensing this is actually possible for most maize farmers in South Africa as soon as the first images become available in December and early January. This is also the period that prices are gradually inclining before the next seasons crop takes the toll.


Smart sampling has given direction and corrective measures have been adopted to improve the yield consistency over the study area. The even colours and yields on images of later years prove the point. Gradual movement to grid sampling has taken place for specific areas of adjustment and smart sampling will be carried out for reference purposes.


Soil classification maps are most important for agronomists and engineers to design their prescription crops and cultivation practises for a specific area.
Soil profiles, as these four shown, are all found in the 50 ha area of the proposed centre pivot scenario as discussed.


Using the physical soil properties such as clay percentage, soil depth and water retention, the designers have more factual information to take their decisions on.
The clay percentage would be indicative to the possible tillage operations that are going to be used to cultivate the area. Prof. A. T. P. Bennie would classify this soil as a sandy clay loam soil between 18% and 35% clay. Cultivation practises of not deeper than 250–300 mm should be used.
Soil depth and water retention in soil profiles as these are most probably easier to manage and constant design norms used to achieve the final goal. However the four profiles are all found on the one area of 50 ha of the given pivot scenario.
The water retention, soil depth and elevation could now be used to design the specific water distribution pattern of the centre pivot.
Have we ever discussed the possibility of designing a centre pivot to deliver differential water distribution?


Elevation planning and land levelling are all factors that modern engineers aught to be able to design and prescribe land forms and contouring of areas to most efficiently prevent soil erosion in any specific area of the cultivated land. Water infiltration rates could also be addressed if the adjusted gradient of the land has been altered.
These are the items the agronomists and soil scientists should be comparing to determine whether the elevation and clay percentages should be altered to be more uniform and cost effective over the long run.
The tillage operations and implement choices are all items that could play a roll in the most productive utilization of the area. The clay percentage and soil depth are indicative of the types of tillage operation that are going to be used to farm the area.
Precision farming has the ability to monitor the work to be done and to report back on the work that has been done, however the design of these implements to do the prescribed operation on the specific position is the key question and needs to be addressed.


In the future remote sensing and yield mapping tools could become important in farm activity planning. The methods precision farming, as most of you are probably aware, in farm activity planning could be used to decide what has to be done on any specific part of the farm.
Using the examples shown and data collected one can run through a possible scenario of typical centre pivot irrigation planning. The placement of the pivot is simply straight forward.

  • The soils have been duly examined and described.
  • The centre pivot area has easily been calculated.
  • The availability and surety of water quantified.
  • The elevation and pressures determined.
  • The design can be completed.
  • The process seems simple to plan.

Designing centre pivots to distribute water at differential rates over the whole area as needed at any specific point. Engineers will have to come up with the solutions to these requests. These are the areas that, in the future, require innovative thinking.


The areas of operation that has been addressed over the past couple of years are the broadcasting of lime and gypsum at differential levels according to the grid sampling analysis of the soil samples.
The designing and production of differential application spreaders in South Africa has been a tedious process. Most of the systems have been designed and built locally by trail and error. With the available equipment, the people involved in these activities have done excellent jobs.
Combining different appliances from quite a number of suppliers has been the most used source to overcome the problems of time needed for research and development of these specific types of appliance.
Equipping the vehicles with apparatus from abroad has become a full-time occupation of many young and adventures people. Making these systems work has been a marvellous achievement and a great breakthrough for South African entrepreneurs.
The use of light bars and auto-steering aids has also improved the efficiency of the operations significantly.


Hay making

  • Hay making has not seen great strides in precision farming. However, if one looks at the possibilities and taking into account the success, precision farming on established grazing and pastures, could be of major significance.
  • All the standard mythology of precision agriculture can be applied in this farming enterprise and could only deliver greater results.

Game farming

  • The flight pattern of a recent game count on a game farm proves of the accuracy of data captured by precision methods.
  • The pilot uses a GPS to determine transects to be flown. A second GPS or DGPS port is dedicated to record the flight route. This serves as proof of the area covered and route flown.
  • A data capturer logs all the game species, sex, age and count. Each species has its own layer. All species appear in the summary page as shown.
  • Distribution of animals and habitat can be defined this way. Annual or bi-annual counts could be compared and informed decision taken with respect to game and veldt management. Data such as available watering points, veldt and erosion condition can also be logged during this flight.


Although precision agriculture holds many advantages and challenges, there are limitations. These limitations will be overcome in future, but need a tremendous effort to keep the system functional.
It does appear that laboratories for soil analyses seem to be on the limited side. Thousands of soil samples are now being analysed due to the gridding of areas for precision farming. Before this period the number of samples was significantly less and the laboratories could cope. The unit costs of soil analysis seems to be high in the light of the new volumes that have to be analysed.
Development and research of the much needed apparatus for the precision farming will have to be introduced as soon as possible. The equipment used is costly and a wrong decision when buying equipment could be fatal. Advice on technical detail and analysis of collected information is crucial.
Skilled people in the precision farming era would have to come forward to assist in the interpretation of data and utilisation of resources to be applied. These experts would most probably be the post graduates and employed by larger fertilizer companies.
Extension officers in the field would also be of great assistance to new comers to the practise.


Many challenges lie ahead of us in the precision farming field. Opportunities for young enthusiasts are falling open and great satisfaction on the side of entrepreneurs is showing the systems are here, they work, but need to be improved and applied.


The future needs of precision agriculture could be defined as two major issues; Education and training and the application of precision farming systems.
Education and training for all categories of skilled people is a must to achieve greater success. Engineers, technicians, artisans, salesman, farmers and employees are to be trained to utilise this concept even more.
The application of precision agriculture equipment has to be well structured. The basic equipment and advanced equipment aught to be managed. The understanding of global positioning systems and computer software, to process the data, would have to be addressed.


There are various resources and companies waiting to assist new comers in the precision agricultural era. Using the opportunities available will result in generous and quick progress in this relative young field. The time is right for major changes in the agriculture. Profitability will be tested on a daily basis to determine if the agriculture will survive.