Indonesian scientists at the Bogor Agricultural University (IPB) are currently fine-tuning a satellite-based technology they have developed to better help oil palm growers accurately diagnose and dosage fertilizer needs for their crops, and thus cut down on an important cost factor in the maintenance of an oil palm plantation.
The multi-disciplinary IPB team of scientists, working together with state-owned PT Pupuk Kalimantan Timur, are trying to improve data collection for the Precision Agriculture Platform for Oil Palm (Precipalm) a system that use satellite imagery to provide accurate information on the spread of nutrients in a palm oil plantation, one of its main scientists, Kudang Boro Seminar said on Thursday (9/7).
Seminar, who is the Dean of the Agricultural Technology Faculty at IPB, said that research have found that the leaves of the oil palm trees were the best indicators of the nutrient content of the soil around the three.
Precipalm developed a model that allows the analysis of satellite images of the foliage of a plantation to indicate what are the deficient or excessive nutrients found in any specific area of a plantation and thus allow the determination of the precise amount and type of fertilizers needed there. Fort the time being, Precipalm only deals with main nutrients such as Nitrogen, Phosphor, Potassium, and Magnesium and a select number of secondary ones.
“The weakness of satellites is when there are cloud obstructions, smoke and low light,” said Seminar, adding that those obstruction hindered the quality of the images and thus rendered difficulties in interpreting the condition of the foliage. “Therefore, we are currently developing a radar version of Precipalm that would not be affected by lighting, clouds and smoke.
The Precipalm application is supported by imaging data from the Sentinel 2 satellites — 2A and 2B — released by the European Space Agency (ESA). The satellite is able to capture images with a temporal resolution of 10 meters by 10 meter using sensors in 12 bands.
Seminar told a webinar on technical systems and informatics in agriculture, held by the Department of Mechanical and Biosystem Engineering Study at IPB, that the combination of the use of radar and satellite imagery would be able to overcome the weakness posed by the visual obstructions as radar imagery was not affected by them.
“We already have a backup system. If we cannot see with the use of satellite, then we could use the radar,” Seminar said, adding that the radar would send electromagnetic waves from Sentinel 1 satellites while the imagery would be taken by the Sentinel 2 satellites.
The two modes used different systems, he added, with the satellite imagery using image transmission over bandwidth channels while radars emit electromagnetic waves to produces spectral images containing information from across the electromagnetic spectrum.
Under the conventional system, growers had to physically take samples of leaves and soil and have them analyzed in a laboratory to get recommendation for fertilizers but the process needed time (depending on the distance to the laboratory and the length of the queue) and the cost of analyzing one single sample is already quite costly too. The accuracy and reliability of each laboratory also differed and thus needed serious consideration too.
Precipalm allows a relatively quick and real-time soil nutrient measurements and fertilizer recommendation that is also transparent and can be done any time in line with the needs of users, without having to gather samples and thus save time and costs.
Seminar said that the technology is currently still at the research stage and commercialization would not begin before the completion of comparative tests that will last for two years, where Demo plots, one fertilized using the Precipalm recommendation and the other using usual fertilizing methods of the company would be monitored and their results compared, especially in terms of fertilizer amount and crop productivity.
The saving generated by a more optimized used of fertilizers was important as fertilizer costs took about 40 to 60 percent of total maintenance costs in an oil palm plantation.
Current accuracy level for the application was above 91 percent for nitrogen content estimation while for potassium and phosphor the rate was at above 82 percent. For magnesium, which had only begun to be monitored recently, the accuracy level was already around 71 percent.
But he also cautioned that no matter how accurate were the recommendation produced by the system, the application in the field was also equally important. The manpower needed to be able to administer the precise dose of fertilizers at the appropriate time for effectiveness.
Precipalm is currently a proprietary software and the team is not selling it as a software but provides services using the software to oil palm plantation companies