The science of soil, the language of the land

This story was originally published by WWF-Asia Pacific Expsoure. WWF-Thailand has various freshwater-related projects ongoing in the country's northeast region, including fish conservation zones, community-managed forests, and compost fertilizer production. Every now and then, the team visits the local communities they work with to share and exchange knowledge and information. Nanticha Ocharoenchai, a communication consultant for WWF-Thailand, was able to tag along with the team on one of their trips to the Baan Sam Phong community and interviewed the locals about their experiences with organic fertilizer—this story is told from her perspective.

Driving through a bumpy dirt road into a seemingly endless field, we finally arrive at a small wooden house where two men are waiting for us out front. Right away, they enthusiastically began to share their experience shifting from chemical to organic fertilizer. 

The shift was triggered in 2005 when the price of chemical fertilizers rose. That year, farmers in Baan Sam Phong community in Nakhon Phanom, a province near the Mekong River in Northeastern Thailand, began to face financial challenges.

Twenty-four members of the local community, all rice and rubber farmers, decided to meet to find a solution. They formed a group to make organic fertilizers together to reduce their farming costs. Once a year, the group creates a mix of manure, sugarcane bagasse, bio-fermented water, and a small amount of chemical fertilizer to share among themselves and sell in the village. Although the aim had been to relieve their financial woes, an additional benefit came about when water pollution in the area began to decrease.

My colleagues and I decided to visit the group’s president Decha Tiyabutr and village headman Tinnakorn Phromsi to understand more about the impacts of compost fertilizer on agriculture, freshwater ecosystems, and the community’s livelihood.

“We used to need eight sacks of chemical fertilizers for every six rai of rice fields. Now with organic fertilizers, we only need three,” Decha says. “Chemical fertilizers cost 600 baht (USD 20) a sack, while organic fertilizers are 23 baht each (USD 0.70). Clearly, we’ve reduced a lot of costs.”

But what about the soil and quality of the produce being grown? In a report, scientists concluded that “there are 17 nutrient elements that most land plants need for productive growth and development: carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium...and molybdenum.” How do Decha and Tinnakorn measure these chemical elements and other biological and physical components of the soil in the real field without any lab equipment? The answer is in the soil itself.

“Organic fertilizers make the soil soft enough for earthworms to live in,” Tinnakorn said. “Good soil has earthworms.”

In scientific terms, the physical texture of the soil determines how fast water can flow through it to reach plant roots, and how much water it can hold. Soft soil allows for root growth and for earthworms and other animals to move around freely and in return, create space in the soil for water and oxygen to penetrate through.

The presence of these small higher-level predators is also evidence for the quality of the biological component of the soil. A healthy ‘soil food web’ has sufficient amounts of organic matter which they can feed on before they are consumed by larger vertebrates such as birds.

Closeup of a rice field

“Now, there are fish and frogs in the rice fields. They eat the manure from the organic fertilizers,” Tinnakorn said.

“Manure makes plants beautiful,” Decha added.

Just as important as the small animals are for soil health are even smaller decomposers such as bacteria and fungi, as well as pathogens and parasites—and manure is extremely abundant with food for these microorganisms.

“We have been using chemical fertilizers ever since my parents’ generation. But my grandparents used to use cow and buffalo manure,” he said.

The organic compounds available in manure have a chemical composition with the optimal supply of nutrients for the plants to grow and reproduce in. Too few essential nutrients and the plants might die. Too many and they won't grow well.

“When we use chemical fertilizers, our vegetables grow green quickly, but they lose that color in a couple of weeks,” Tinnakorn said. “Now we have changed to organic fertilizers, they stay green much longer.”

Besides these indicators, both the farmers have also studied the health of their land through various indirect methods, particularly by observing the water.

“The fish in the rice field would feel ‘leathery’. Some fish only had heads, and their tails would be worn off,” Decha said.

“When we used only chemical fertilizers, I would get itchy and my skin would get leathery, too. Each time I went into the rice fields I would get infections from the water.” Tinnakorn added. “The water quality has improved since we changed to organic fertilizers.”

Since 2015, WWF-Thailand has supported this initiative through capacity building which has helped the group to grow to 35 members. In partnership with HSBC, WWF has supported the group with seed funding which now helps each member produce a share of around 7,700 pounds of organic fertilizer each to use and sell.

With more interest and manpower from their neighbors, Decha and Tinnakorn have taken the role of educators, sharing their knowledge and practices with their own community and others. Now able to produce their own from manure and organic compost which would otherwise have been wasted, they are not only able to save expenses on chemical fertilizers and protect freshwater sources but also generate extra income and empower other farmers.

Combined, these local communities accumulate decades—and generations—worth of wisdom valuable to sustainable agriculture and environmental conservation. Through care and observation, it is they who can touch, feel, and sense the land, the plants, their health, and their growth, sometimes better than chemical test kits and lab equipment, using none but their naked eyes, bare hands, and full heart.