The threat posed by climate change is well documented and often debated. While specific regional impacts appear well nigh impossible to forecast, there appears to be expert consensus that extreme climatic events will increase in frequency and intensity, and in southern Africa specifically, the eastern coastal regions will become hotter and wetter, while the west and interior will become dryer. Certainly extreme climatic events appear to be on the increase worldwide.
It is generally expected too that in South and southern Africa the amount of water available for agriculture will become increasingly constrained in order to meet domestic and commercial requirements. This prioritisation of resources is already evident in the Western Cape.
At a macro level the group’s response to this threat has been to geographically diversify its operations through southern Africa to avoid concentration in a single climatic region. As the recent drought showed, however, extreme events can occur over large areas simultaneously.
At a micro level we aim to use technology and hone our management techniques to conserve our natural resources and to derive maximum benefit from the scarce water and land resources at our disposal. The ability of the region to overcome food security risks will depend on optimal resource utilisation.
Cane field devastated by drought
To mitigate climatic risk further we endeavour to produce a variety of crops in climatically optimal locations. We constantly trial alternative crops that have potential in our farming regions to optimise output from scarce resources. Sometimes tough trade-offs are required. During the 2015/16 drought in Mpumalanga, cane lands had to be sacrificed to provide water for higher return banana plantations.
Where it is economically viable we establish water storage facilities to at least partially meet seasonal demands, rather than rely entirely on over-stressed perennial rivers. This enables us to capture excess flows without upsetting delicate riverine ecosystems.
In an environment where water availability is critical, having sufficient water allows the Group to manage the crops effectively. To ensure a secure water supply each farming unit has developed an extensive network of dams and pipelines.
In the drought-stricken Western Cape our on-farm water storage has proved vital in providing adequate water to produce our 2018 crop.
A large water reservoir on the Amanxala Estate near Komatipoort
Crookes Brother follows an irrigated cropping strategy for the large majority of its farming operations to mitigate climate risk. Only 7% of the total area under cultivation is purely rain-fed. As we have often experienced, however, irrigation does not eliminate drought risk, and it is critical to manage water resources effectively to achieve optimal results.
Effective irrigation management includes optimal system design to enable the right quantity and quality of water to be delivered to the right area at the right time at minimum cost; constantly monitoring soil moisture to determine water requirement via probes and satellite imagery; monitoring results to adjust irrigation schedules and plans; and ongoing maintenance to avoid wastage.
Gravity fed flood irrigation is gradually being replaced by more efficient irrigation systems
Our irrigation systems are constantly being re-evaluated and systematically upgraded to improve effectiveness and efficiency. Over the past eight years we have implemented a programme on our cane estates to replace inefficient sprinkler and furrow systems with drip. To date we have installed drip irrigation on approximately 2 200ha out of 7 000ha under irrigation on our cane estates.
The graph below shows the completed and planned conversion from inefficient irrigation to more efficient irrigation systems.
Drip irrigation has many advantages over traditional overhead and flood irrigation systems:
- Drip systems use less water due to more efficient placement and low evaporation.
- Less water means less electricity used for pumping.
- Drip assists with weed control as there is no moisture in the inter-row.
- Drip assists in the efficient application of fertilisers and pesticides – costs are also much lower versus tractor or aircraft application.
- Efficient placement means less fertiliser and lower pesticide losses.
- The above factors significantly increase yields under drip systems.
Efficient pump and filter station, controlled by VSDs