A targeted approach to soil assessment, first developed through an ACIAR partnership with the Department of Science and Technology - Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (DOST-PCAARRD), is reshaping how the Philippines understands and manages its agricultural landscapes. By providing the evidence needed to match land suitability with cropping decisions and ways to improve soil condition, this approach is helping farmers and governments address longstanding declines in productivity and soil health.
The linchpin for this transformation is an innovative use of soil testing and soil-mapping technology. It was applied in the Philippines starting in 2019 to identify the most viable and productive cropping systems across farming areas with varying soil characteristics. The same data are also used to identify the most cost-effective way to fertilise and remediate soils in ways that better sustain crop-production systems.
The impacts are of such significance that they prompted the Philippines Government to aim for a National Soil Health Strategy.
This followed an earlier adoption of the soil-mapping technology by the local government of the Agusan del Sur province, the Philippines's fourth-largest agricultural province.
The Soil and Land Management program
The approach taken in the Philippines stems from the ACIAR Soil and Land Management program, currently led by Dr Johnvie Goloran.
He explained that in its original form, the project used Australian laboratories to process thousands of soil samples collected in the Philippines.
'Samples were used to type soil characteristics across the landscape in ways that result in "land suitability" maps,' said Dr Goloran. 'These allowed us to identify or devise the cropping and intercropping systems most likely to prove profitable in different farming districts.'
Importantly, the same data were used to identify the soil-improvement and soil-remediation practices most likely to boost soil health and, therefore, yields. Once identified, they were costed to identify the most cost-effective interventions for smallholder producers.
The turning point
Impacts on farm profitability first became apparent within an ACIAR project that ran between 2019 and 2024 in the Agusan del Sur province. That project partnered with Indigenous smallholder farmers and introduced a profitable rubber intercropping system.
'Rubber is the fourth-largest crop in the province, but only 50% of the total area planted is productive or tappable,' said Dr Goloran. 'Major constraints included a consistently low price for natural rubber latex. This left farmers with no other livelihood options or source of income under a rubber monocropping system. The ACIAR project reversed that by introducing income-earning cropping systems to rubber plantations even as work was done to rejuvenate the rubber production systems.'
Providing training and support on soil and nutrient management was central to those efforts: 'We were able to take a new approach by applying costed land-suitability information.'
Mr Felicidad Merin, a participating Agusan del Sur farmer, saw the impacts firsthand.
'It has been a big help for us farmers because we learned the correct way of collecting soil samples and applying the necessary fertilisers for our crops. Because of this, we were able to improve our situation and our income compared to before.'
Trials found that the improvements were substantial. An example was highlighted in figures that were tabled in the Agusan del Sur legislature. When tested in challenging rice production systems, the soil-data-based fertilisation strategy increased yields from an average of 4 tonne per hectare (the national yield threshold for rice) to 6.16 tonne per hectare.
Importantly, that extra yield translated into a net-income gain for farmers of 263% while concurrently reducing fertiliser costs by 45% compared with existing farmer practices.
A soil-healthy future
As the benefits became ever more apparent, the local government started paying close attention. This had two important consequences.
A dialogue opened between the project partners and the local government regarding soil policy. That culminated in 2023 in the National Soil Health Summit where President Ferdinand Marcos Jr recognised the importance of healthy soils and pledged long-term support. Soon after, a Memorandum of Understanding was signed, formalising Australia's commitment to support the development of the Philippines National Soil Health Strategy through research, capacity development and knowledge exchange.
Additionally, the Provincial Government of Agusan del Sur - an ACIAR project partner - also opted to establish its own soil testing facility. This opened in 2025 with the inauguration of the Agusan del Sur Soil Laboratory. It is now providing modern soil-testing capability in support of the National Soil Health Strategy.
The new laboratory can analyse up to 100 soil samples a day and provides fast and affordable soil-fertility recommendations. This empowers farmers to apply nutrients more efficiently, cut costs and increase yields.
Mr Santiago Cane Jr, Governor of the Province of Agusan del Sur, explained the reasoning behind this investment:
'Agusan del Sur's land is our lifeblood,' he said. 'Through DOST-PCAARRD and ACIAR's partnership, we're helping farmers care for the land, grow more, and build a sustainable future for generations to come. Every seed sown in Agusan del Sur tells a story. With DOST-PCAARRD and ACIAR's guidance, our farmers are empowered to grow sustainably, leaving a lasting legacy for our community.'
The laboratory also strengthens the technical capacity of local governments and extension workers while serving as a hub for farmer training and demonstration of best practices. ACIAR is also providing technical support to this laboratory through Griffith University in Australia.
Mr Regie Apolonario, an Agricultural Extension Officer in Agusan del Sur, welcomed the capacity building offered by the laboratory: 'The soil health laboratory is a great help because the soil can be checked and analysed to know what is appropriate and suitable to plant, and the type and amount of fertiliser needed,' he said.
A new venture
Central to the project's impressive impact is ACIAR's deep and longstanding relationships with Philippine partner organisations and smallholder farmers that date back to 1983.
The tradition continued with the launch in November 2024 of a new $3.4 million ACIAR partnership that will continue to develop soil knowledge, information and capacity.
The new project will continue to develop cost-effective soil testing methods and information across more provinces and work to support the development of the National Soil Health Strategy. Professor Chengrong Chen from Griffith University will carry over his leadership role from the rubber- intercropping project.
Romelyn Bacsarpa, an Agricultural Extension Officer in Agusan del Sur, is among those on the ground who is also keen to see work on soil health continue.
'ACIAR has been a great help and blessing,' said Romelyn Bacsarpa. 'Because of ACIAR's support of soil improvement through its programs and research, farmers were able to understand the quality and capacity of the soil through soil testing.'
Of particular importance to the progress are the partner organisations in the Philippines that worked with ACIAR, including:
- Department of Science and Technology - Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (DOST-PCAARRD)
- Philippine Department of Agriculture
- Agusan del Sur State College of Agriculture and Technology
- Provincial Government of Agusan del Sur together with its municipal local governments
- farmer groups.
Together, this partnership has highlighted the role healthy soils play as the foundation of food security, farmer prosperity and climate resilience.
'Sustained investment and collaboration are needed to keep soil health at the centre of agricultural development,' said Dr Goloran. 'By supporting evidence-based policy, empowering farmers and strengthening institutions, the Philippines can secure its soils - and its future - for generations to come.'
