How to design a drip irrigation system that works with your tractors and harvesters

Climate change is leading to increasing water scarcity. Agriculture is the biggest user of water in South Africa. Appropriate methods and systems of irrigation are, therefore, critical to the objectives of achieving higher irrigation efficiency to achieve the much-needed savings in water usage. To achieve water savings and remain profitable, farmers must pay careful attention to how their chosen irrigation systems affect other operations on their farms and how the chosen irrigation systems affect mechanisation activities such as planting and harvesting operations. Precision agriculture uses modern methods for mechanised operations in the farming enterprise.

By Celi Mbokazi and Dr Macdex Mutema of ARC-Natural Resources and Engineering, Agricultural Engineering Campus

In this article, the focus is to discuss how a drip irrigation system affects mechanisation operations and how a combination of precision agriculture and a modern drip irrigation system design can lead to optimal irrigation and mechanised operations resulting in reduced costs and increased profitability.

Also read: Expert advice | Turn rainwater into profit – smart water storage strategies for farms of all sizes

Land preparation

Drip irrigation is typically considered a permanent irrigation system because the system is not moved for at least the entire growing season and can stay in place for multiple growing seasons. Since the system stays in the same place for a considerable period, careful consideration must therefore be given to the layout of the system such that there will be pathways for example for mechanisation equipment such as tractors and other farm machinery. To achieve this, special tools and considerations as discussed below need to be applied.

GIS Mapping The use of Geographic Information Systems (GIS) software to precisely map the farming field and area for irrigation has emerged as a popular method for precision agriculture. Every area of the field is mapped to within a centimetre to optimise the planting area while making clear layouts of where the tractor wheels must pass. To achieve this, the type of tractor (two-wheel or four-wheel) as well as tractor width should be known for the precise design of the layout.
Crop type Drip irrigation is popular in orchard farming due to the ability to directly target the root zone of the orchard. In addition, land preparation for orchards happens once in the production life span. With orchards, harvesting equipment also need access to the field. This is in the form of trucks rather than harvesters. Thus, some of the pipes may have to be buried underground to ensure safe passage of heavy equipment. This can be achieved through a combination of precise mapping and design to ensure optimised access points and routes in the field.

Photo for illustrative purposes: Henna du Plessis

Skilled labour

Handling or the ability to operate precision agriculture equipment requires highly skilled operators. The use of unskilled labour can easily cause damage to the irrigation pipes, which are quite expensive. Tractor wheels can also damage the pipes if the driver is not sufficiently skilled. The drip irrigation system is expensive to install and fragile to operate; hence, this system needs literate handlers who are good with numbers to control the irrigation scheduling with the assistance of appropriate software. In addition, combining mechanisation planning with optimal irrigation scheduling requires a skilled overall farm manager. Therefore, all levels of labour must be skilled to achieve optimal results in terms of asset utilisation while minimising water use with the drip irrigation system.

Also read: Farmers are going digital and it’s changing how agriculture works

Weeding and pest control

Drone spraying technologies
Drone spraying is a new method of spraying and is ideally suited for drip irrigation because there is no ground movement of equipment during spraying. The challenge with drone spraying is mostly due to regulation as operating licence can be a challenge to obtain as well as the associated costs.
Elevated spraying vehicles
This specialised equipment has enough wheels to pass between rows, while being elevated enough to be above the crop. The irrigation layout and selection of the equipment must both be considered to ensure synergy when operating the drip irrigation system as the pipe layout is of a permanent nature.

Harvesting

Drip irrigation may be unsuitable for crops such as wheat that have specialised harvesting equipment and tight spacing. The harvester header is very low during harvesting; therefore, pipes cannot be above ground. In addition, costs may be prohibitive since wheat is grown in larger hectares.

In summary

Drip irrigation is preferred in high cash crops such as orchards where spacing for mechanised equipment is easier to achieve and land preparation activities are infrequent.

Enquiries: mbokazic@arc.agric.za or mutemam@arc.agric.za