Saving our soil: Why soil test-based fertilization is necessary for optimum crop production

Farmers can have a good source of income if their produce is healthy and fresh. (Henrylito Tacio)

By Henrylito D. Tacio

Some 86 years ago, American President Franklin D. Roosevelt penned a thought-provoking letter addressed to all state governors urging them to find effective soil management practices in their respective areas. “The nation that destroys its soil destroys itself,” he wrote.

That statement was quoted by Dr. Johnvie B. Goloran, an agricultural and environmental scientist, in a lecture delivered before a group of farmers who attended a forum that was held in Prosperidad, Agusan del Sur.

An agricultural and environmental scientist who specializes in soils. (Henrylito Tacio)

When it comes to farming, the discussion almost always focuses on the following subject matters: pesticides, hybrid seeds, fertilizer, and mechanization. More often than not, soil is not included in the issues that matter.

To think, healthy soils contribute 40% to 60% of the yield potential of the farm. Yet, when he asked them if they knew the soils of their farms, not one raised his hand. “We need to get to know our soils: Healthy soils produce healthy food and healthy people, and also support a healthy environment,” he said. “Knowing the health of your soil is worth investing in.”

Dr. Goloran has a PhD in soil science and postdoctoral training in soil health and plant nutrition from Australia’s Griffith University and the Laguna-based International Rice Research Institute, respectively.

Just like the crops grown and livestock raised, soils need tender loving care from farmers. “But how will you take care of your land if you don’t know the soil?” he asked.

 Not sexy

Most reporters don’t write about soil as editors don’t find the subject sexy; it doesn’t have the news appeal of climate change, deforestation, and plastic pollution that attract the attention of readers.

Soil should as its degradation is a more pressing problem than global warming, biodiversity loss, or any other environmental crisis, according to the UN Food and Agriculture Organization (FAO). In fact, FAO considers the preservation and restoration of the health of the world’s soils as “the most pressing urgent matter humanity faces.”

Such a claim is no exaggeration as humanity depends on fertile topsoil to grow the food that counteracts hunger. Unfortunately, more than a third of the world’s soil is already degraded.

The Nobel-prize winning Intergovernmental Panel on Climate Change (IPCC) estimates that it could rise to 90% by 2050 “if nothing is done.” Even moderately degraded soil produces 30% less food.

“I am very sure no Filipino farmer wants their fields to be infertile or degraded,” Dr. Goloran explains in an exclusive interview. “However, most farmers don’t know their soils. Because of this, they lose the opportunity to design or develop a strategic program/practice suitable for their farm lands.”

Dr. Johnvie Goloran showed a study where rubbers are planted in a soil-tested farm. (Johnvie Goloran)

Soil infertility

“I believe the lack of soil information among farmers is the main cause of soil infertility,” he further says. “The factors that we have been observing now – such as over tillage and excessive fertilizer applications – are just simply manifestations of this reality that farmers have no physicochemical information on their farm lands.”

Experts claim one of the most pressing problems that cause soil infertility in farms is erosion, which Dr. Goloran defines as “the removal of the topsoil or the nutrient-rich soils via run-off or leaching.”

Topsoil is related to the earth much as the rind is related to an orange. It is the link between the rock core of the earth and the living things on its surface. It is also the foothold for the crops farmers grow. 

In crop production, topsoil is the single most important resource. What most farmers don’t know is that topsoil built up over time. Pundits say it takes 200 to 1,000 years to form 2.5 centimeters of rich topsoil. 

Soil erosion

On the average, farmlands are losing 2.5 centimeters of topsoil every 16 years, or 17 times faster than it can be replaced. No thanks to soil erosion.

“Soil erosion is an enemy to any nation – far worse than any outside enemy coming into a country and conquering it because it is an enemy you cannot see vividly,” said Harold R. Watson, an American agriculturist who used to be the director of the Mindanao Baptist Rural Life Center in Kinuskusan, Bansalan, Davao del Sur.

The reason why crops – cereals, fruits and vegetables – grow in fields is because the topsoil contains lots of nutrients. “Some forms of nutrients such as phosphorus and nitrate are highly mobile in water,” said Dr. Goloran. “As such, these nutrients are prone to leaching or surface run-off. This is the reason why minimum tillage and cover cropping are recommended as these provide protection of the topsoil.”

Farms provide good harvests when they are properly fertilized. (Henrylito Tacio)

In minimum tillage, the soil is not turned over in contrast to intensive tillage, which changes the soil structure using ploughs. Cover cropping, on the other hand, is used to keep the soil protected with plants that may or may not be used as an additional cash crop. 

In a natural state, plants grow and die. The nutrients they contain return to the soil and new plants use them to grow. But agriculture disturbs the cycle: farmers harvest the plants and people eat them. 

Even in the past, farmers have unearthed several ways to prevent crop yields from declining over time. “First, farmers need to have good soil information for their farm lands, and based on these soil data, they can develop a suitable nutrient management practice for their farms,” Dr. Goloran says. 

Soil testing

 This is where soil testing comes in. The goal of soil testing is to provide farmers an accurate assessment of the soil’s fertility to make proper fertilizer recommendations. 

“Soil testing gives you the critical information on the nutritional status of your farm,” Dr. Goloran says. “This means that farmers would be able to select what type and rate of fertilizers are suitable to maintain a good nutritional status of the soils and at the same time address the nutritional requirements of the crops.” 

Farmers can have a good source of income if their produce is healthy and fresh. (Henrylito Tacio)

Soil testing is very different from leaf tissue nutrient analysis, which determines if the crop has had a sufficient supply of essential nutrients. Dr. Goloran explains: “The difference between soil testing and leaf tissue nutrient analysis is that with soil testing, it is a preventive approach against crop nutrient deficiency while leaf tissue analysis is more of a curative approach. With the latter, this means that our crop has been under stress due to nutrient deficiency that may result in poor yield and quality of the produce.” 

Farmers can have their soil tested through the Regional Soils Laboratories (RSLs) under the Department of Agriculture. “It would be great if they can do or analyze at least 8 to 12 available forms of soil nutrients,” he says. 

In his lecture, he cites the case of phosphorus, a critical nutrient for plant growth. By conducting soil testing, a farmer will know if his farm has less phosphorus. If the result shows that it lacks phosphorus, then he needs to provide the nutrient to his farm. But if the farm still has lots of phosphorus, applying it with phosphorus is not necessary. In fact, putting more phosphorus makes the farm acidic, which is not good for crop production. 

Soil testing can really help farmers in optimizing their crop production. “The standard practice should be that farmers would get not just the soil test results but also a set of recommendations for the crop that they prefer to plant on their farms,” Dr. Goloran says. 

Doing so, the farmer can have a saving. “You don’t give your plants what they don’t need,” he says. 


Commercial fertilizers have been called one of the greatest inventions of the 20th century. Without it, pundits say almost half of the world’s population would not be alive today. 

“Actually, there are prerequisite activities prior to giving fertilizer recommendations,” he adds. “Soil test results must be calibrated with crop growth and yield to ensure better response of soil test-based fertilization. This is something to be clarified with the RSLs.” 

Dr. Goloran, by the way, has a strong background in developing, implementing and managing research projects in soil health and plant nutrition that have resulted in high-cost savings and improved efficiency of fertilizer programs and farm management practices, particularly in large-scale commercial farms. 

He was a former director of agricultural research and development of Dole Philippines Incorporated, where he provided agronomic technical support to the plantation. He also led the company’s regenerative agriculture program.

Fertilizers are composed of main nutrients, macroelements, and microelements. The main nutrients are nitrogen (N), phosphorus (P) and potassium (K). Macroelements include calcium (Ca), sulfur (S), and magnesium (Mg). The microelements are composed of zinc (Zn), copper (Cu), molybdenum (Mo), boron (B), manganese (Mn), and iron (Fe).

 “For many years, farmers have only known NPK from the so-called complete fertilizer (14-14-14,” he says. “Actually, there is no such thing as being complete with only 3 macronutrients. I usually tell a joke on what NPK stands for. In Cebuano, it means ‘naa pay kulang.’ In Tagalog, it means ‘naloko pala kayo.’ The key point here is that we need to provide the necessary nutrients needed to address the crop nutritional requirements without depleting the nutrients in our farms – to keep them healthy.” 

Eggplants harvested from a trial study. (Johnvie Goloran)

Natural vs. synthetic 

Farmers can use both organic and inorganic fertilizers to restore the fertility of their farmers. “We have to understand that organic and inorganic fertilizers are both food to crops,” he points out. “The former takes time as it needs to be mineralized before it will be taken up by the plants. The latter is already available for crop uptake.” 

Farmers are also urged to understand the time element on the effects of both organic and inorganic fertilizers. “If their crops need urgent attention, farmers have an option which one to choose,” Dr. Goloran says. “One thing that I would like to emphasize, regardless of fertilizer sources, be it organic or inorganic, both require soil testing as a prerequisite, so that farmers would know the rate and type of fertilizer to be applied to their crops.” 

Both organic and inorganic fertilizers have drawbacks. “Both have disadvantages when we are talking about excessive rates of application,” he points out. “I think the discussion should not only be about the sources or types of fertilizer but about the rate. At the moment, farmers do not have the luxury to determine the appropriate rate because they do not have the critical soil information.” 

Help from government

This is where the help of the government comes in. “I think we should define soil infertility based on the quality of soil test results,” Dr. Goloran says. “This area should be given priority investment by the government and non-government organizations or the private sector.”

Currently, Dr. Goloran is working on a project in the southern part of the Philippines, which is funded by the Australian Centre for International Agricultural Research (ACIAR) and Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD). 

The main objective of the project is to help smallholder farmers increase their income via effective soil and land management of rubber-based cropping systems. It has a strong emphasis on the development of an effective fertilization program that can support the complex nutritional requirements of diverse crops. “The key here,” he says, “is soil health.” –

Photos by Henrilito Tacio and courtesy of Johnvie Goloran

What is your reaction?

In Love
Not Sure
Agriculture Monthly magazine is the Philippines' best-selling magazine on all things agriculture. It is packed with information and inspiration on how to make the most of your farm or garden.

    You may also like

    Leave a reply

    Your email address will not be published. Required fields are marked *

    More in:COMMUNITY