The challenge to schedule irrigation

Tests for the viability of a computerised irrigation scheduling system � the MyCanesim system � have produced positive results for small-scale sugarcane farms in KwaZulu-Natal. This despite the daily running of the trials being undermined by powercuts

- Advertisement -

Tests for the viability of a computerised irrigation scheduling system – the MyCanesim system – have produced positive results for small-scale sugarcane farms in KwaZulu-Natal. This despite the daily running of the trials being undermined by powercuts and theft. Lloyd Phillips reports.

Field trials for a computerised irrigation scheduling system for sugarcane farmers began in 2004. T he South African Sugar Research Institute (SASRI), together with the Water Research Commission, Illovo Sugar, the Department of Agriculture and Environmental Affairs (DAEA) in KwaZulu-Natal and the Impala Water Users’ Association (IWUA), began field trials of the MyCanesim system, which has been designed to provide irrigation schedules specific to individual farmer’s farming conditions. The system aims to enable sugarcane farmers and their extension officers to reduce over-irrigation and irrigation costs, while maintaining a high yield of high-quality sugarcane. The MyCanesim system was developed and tested under the guidance Dr Abraham Singels from the SASRI. The field trials set out to evaluate if small-scale sugarcane farmers could implement and benefit from computer-calculated, real-time irrigation scheduling advice.

How the system works

- Advertisement -

“We began the trials in the Pongola area of northern KwaZulu-Natal with only four small-scale sugarcane growers participating,” says Dr Singels. “By the end of 2007, as the trials neared the end of a three-year lifespan, we had nine farmers participating in the evaluation, and a total of 41 out of a possible 47 small-scale cane growers, who collectively farm on over 500ha, receiving advice from the system.” Data is collected by an automatic weather station based at the SASRI’s Pongola research station. On farms, data about farming conditions is collected by the SASRI and the DAEA’s extension officers. Singels explains that each participating farmer has an average of 10ha of land under sugarcane, most of which tends to be on a single field. MyCanesim system gives each farmer field-specific irrigation schedules. The schedules are based on the automatic weather station’s daily recordings, soil properties, on the type of irrigation system in use, on the sugarcane cultivar, on the row spacing, when the crop was ratooned and when the farmer plans to harvest his crop. Once all that data is collected, it’s transmitted to the MyCanesim computer programme based at SASRI’s Mount Edgecombe headquarters and used to calculate irrigation scheduling information. Farmers are then sent an irrigation schedule via text messaging to their cellphones.

An award-winning project

Despite the Pongola scheduling trials only officially ending this month, and Dr Singels still having to write a report, the MyCanesim system has already won the prestigious International Commission on Irrigation and Drainage’s WatSave award for innovative water management. And over the past three years, small-scale farmers participating in the MyCanesim trials, who have adhered to the irrigation-scheduling advice, have achieved excellent results. “We have several farmers who use less than 1 000mm of water to produce over 90t/ha of sugarcane,” says Dr Singels. “Over 2007 the farmer Bahlangene Siyaya has proved to be the trial’s most efficient irrigator. He produced 106t/ha with 748mm of water. Another two of the trial’s farmers, Nhlanhla Mbokazi and Dlokwakhe Mthembu, achieved a Recoverable Value (RV) yield (a measure of sugarcane sucrose content) of 15,86t/ha and 15,20t/ha in 2007.” Etienne de Beer, a sugarcane procurement officer for Illovo Sugar’s Pongola mill, says the farmers who best adhered to the irrigation scheduling advice generally produced better quality and quantities of sugarcane than those who didn’t, or those who weren’t participating in the MyCanesim trials. “We consider our best sugarcane suppliers to be those who can supply the mill cane with over 15% RV content, 87% to 88% sucrose purity and low fibre and extraneous material content,” explains Etienne. Dr Singels believes the success of Pongola’s MyCanesim trial means it’s just a matter of time before it’s rolled out to the rest of South Africa’s sugarcane producing sector.

However, based on experience from the trial, Dr Singels does have some concerns that he feels need addressing to improve the use of MyCanesim by small-scale growers. “We have found that it’s a struggle to get feedback from participating farmers. Feedback is needed for accurate irrigation scheduling information,” he explains. “For this reason, it’s imperative that government extension officers and sugar mill cane-procurement officers remain closely involved with the MyCanesim participants. These officers must regularly interact with the farmers to see how things are going and to find out if there are problems. Generally, we’ve found that if the farmers aren’t routinely guided in their use of the MyCanesim system, some of them start neglecting instructions and eventually neglect their irrigation and other sugarcane production practices. A short period of irrigation can result in lower quantities and a poor grade of sugarcane. Water and electricity bills are also unnecessarily high.” A number of Pongola’s small-scale sugarcane farmers have complained about Eskom’s load-shedding as it interferes with the irrigation schedules issued by the MyCanesim system.

They also complained

One group of MyCanesim trial participants complained that the (IWUA) does not maintain a consistent supply of water to infield pumps. This negatively affects the sugarcane crops. Supply-side difficulties Johann Boonzaaier, CEO of the IWUA, says that small-scale farmers don’t always appreciate that Eskom’s load-shedding, together with the need to replace ageing infrastructure in the irrigation water provision system, poses a challenge to the IWUA’s ability to supply Pongola with an uninterrupted supply of water. “Another problem is that the government’s designers of the small-scale farmer development programme in the Pongola area didn’t accurately calculate the irrigation infrastructure required by the farmers to efficiently irrigate their crops,” adds Johann. “Two or three farmers sharing an infield irrigation pump interferes with the farmers’ ability to adhere to irrigation-scheduling advice and also results in lower irrigation-water pressure when all the farmers irrigate at the same time. Another problem is that the farmers often don’t know how to use the pressure settings on their dragline irrigation systems, sometimes even fitting pieces of equipment in the wrong part of the sprayers.”

The IWUA is also concerned about some of the small-scale sugarcane growers illegally using their water quotas to irrigate nearby maize and vegetable crop gardens. The quotas were calculated on sugarcane production only and when the farmers overextend the irrigation infrastructure, it’s to be expected that water-pressure issues arise. “I have discussed these matters frequently with the farmers in question, but we’ll have to see if they’ll comply with my requests,” says Johann. “They must also understand that when they don’t pay their water and electricity accounts on time, the water supply will be cut off and they won’t be able to irrigate. The farmers are often given some financial leeway in this regard, but the IWUA can’t afford to let the situation go on indefinitely.”

The project’s potential

While such challenges are for the most part beyond the control of Dr Singels and the other scientists involved in the development and implementation of MyCanesim, Dr Singels is concerned about how the promising future of such a valuable irrigation scheduling tool might be affected. It remains to be seen how existing and potential users, utilities suppliers and governmental farmer development initiatives can iron out the wrinkles. Because using the MyCanesim system could result in top-notch small-scale sugarcane farmers and efficient use of scarce water resources. Contact Dr Abraham Singels on (031) 508 74460 or e-mail [email protected].