While most Cambodian farmers prefer to use chemical fertilizers on their crops, hoping to boost the yield of their rice, fruit and vegetables, agricultural experts warn that the use of such chemicals can damage health, soil quality and natural diversity.
Not only can it be harmful to humans, they say, but it can hurt biodiversity, damaging populations of fish, frogs and crabs that farmers depend on to supplement their diets.
Instead, farmers should try to maintain the nutrients in their soil for long-term farming of quality agricultural products, according to Yang Saing Koma, president of the Cambodian Center for Study and Development in Agriculture, or Cedac.
“To do sustainable agriculture, you should feed nutrients into the soil, then let the soil feed the crops,” he said in an interview with VOA Khmer. “If you use chemical fertilizer, you can only feed the crops. And if you only feed the crops, you can only farm for a short time. It is not different from human beings. If you want to feed the baby, you should feed the mother, because the mother is the producer of milk for the baby.”
To maintain crops and soil, he said, farmers should not use chemical fertilizer alone, but should mix it with natural compost to maintain the quality of the earth. Those who don’t are hurting themselves and their livelihoods.
“That person is committing suicide, because this will destroy the soil’s nutrients and the human’s health,” he said. “The disaster will be difficult to undo.”
Unlike chemical fertilizer, natural compost can be used alone. Compost is made up of decomposed leaves, like those from beans and other plants, and animal manure. Decomposed bird droppings can also be used. Farmers who live near the forest can collect forest leaves or jungle soil to make it.
Natural compost fertilizer creates a soil suitable for worms and crop-friendly insects, agents that make the soil more nutritious and healthy, Yang Saing Koma said.
It can be difficult for some people to produce, however, as some farmers don’t have enough plants for their personal needs, let alone for compost.
“There are more benefits from using natural fertilizer than using chemical fertilizer,” he said. “There are not enough bushes for the whole country’s consumption, and it would be difficult to transport them.”
Still, chemicals should be avoided, as they contain acids the reduce the number of helpful organisms in the soil and interfere with plant growth. Such chemicals are easily found in the market, like urea, DAT, 16200 and NPK.
Use of these chemicals can produce bigger harvests in a shorter amount of time, but they come with health consequences that can lead to the need for medical treatment in the future.
Ros Mao, a farmer in Takeo province, described his experience using chemical fertilizer for the rice fields and other crops. The chemicals led to stomach aches and diarrhea for him and his family, so he stopped using it in 2004, choosing natural fertilizer instead.
“I’d lost a lot of frogs, toads, crabs, snails,” he said. “And when I changed to the natural compost fertilizer, I saw those amphibians, reptiles, returning back. After the rainfall I saw them crying and singing. I could see that the natural compost fertilizer did not provide a large harvest, but we won over the environment.”
Sourn Pal, president of the local farmers association in Krain Yov commune, Sa’Ang district, Kandal province, said his group had switched to natural fertilizer and was selling to private companies or the Ministry of Agriculture.
“It can reduce the [money] farmers spend buying chemical fertilizer,” he said. “We maintain sustainable agriculture and our environment is getting better.”
Despite such converts, the use of chemicals remains widespread. In provinces west of the Tonle Sap, such as Kampong Cham, Pursat, Battambang and Banteay Meanchey, farmers are well known for the production of aromatic rice. But most of these farmers use chemicals.
Beung Chamnap, a Banteay Meanchey farmer, said he believed most growers in his province still use chemical fertilizer for their rice. Exceptions are the small farms that grow vegetables or fruit with natural compost.
With the increased use of tractors for plowing, the crops don’t get cow or buffalo manure for fertilizer. Chemical fertilizer is easy to buy and transport, he said, and it produces good results.
“Chemical fertilizer makes the crops grow greener and better than normal fertilizer,” he said. “It made the crops grow faster than natural compost.”
Beung Chmnap said he didn’t know what the effects on health or biodiversity were for the chemicals.
Meanwhile, other farmers in the province have begun to recognize that chemicals can hurt people’s health and the soil. That doesn’t always mean they avoid it.
“We don’t know what to do,” said Pleng Phany, a Banteay Meanchey farmer. “If we don’t use chemical fertilizer, our rice product will be lower than others. For example, they can get from 30 to 40 sacks per hectare using chemical fertilizer, but if we don’t use it, we can get 10 to 15 sacks.”
“People need to have a lot of income, so they need to use the chemical fertilizer, even though it costs a lot to buy,” she said.
Some farmers use up to 150 kilograms of chemical fertilizer per hectare of land, a third of it before they grow the rice, a third during the growing season, and a third when the rice produces flowers and seeds. That’s two or three times per year, depending on a farmer’s economic situation.
Soil quality will improve if they start using natural fertilizer, agricultural experts say.
“The good thing is, when we try to use natural compost fertilizer every year, our soil will get better and better,” said Chong Sophal, dean of the faculty of agriculture at Chomkar Doung University. “Nutrients in the soil will gain year by year after we use natural compost for four or five years.”
Chemical fertilizer works in the opposite direction.
“If we use a sack of chemical fertilizer this year, next year we will need to use more than a sack to maintain our yield at the same level,” Chong Sophal said. “We have to increase it every year. That is making our soil worse.”
Chong Sophal’s faculty is working on a formula for a new natural fertilizer that can be sold next to the chemical version, but they are not sure when it will be for sale.
Experts say the government can prohibit the import of chemical fertilizers that provide little value or destroy soil and health. Farmers, too, need to stop using the chemicals, but they need support; better irrigation, for example, which would produce more muddy soil for crops. Deforestation should be curbed, as well, as it destroys habitat and an important source of rain.
Heng Ratana, an official at the Agricultural Ministry’s secretariat for the System of Rice Intensification, said most farmers using chemicals are in provinces near neighboring countries, where they is easily smuggled in.
The ministry is working to educate farmers to raise awareness about the impact of chemicals and it advises people to save animal manure and collect organic waste.
“The Ministry of Agriculture, the leaders of the ministry, always take much care of the farmers,” he said. “They instruct the famers how to produce natural compost and build a hut or barn to keep it in.”
Some farmers even make a business selling cow or buffalo manure, he said.
Cedac’s Yang Saing Koma has a three-step strategy to improve Cambodian farming, the health of its citizens and its environment.
First, the government should increase outreach programs to teach farmers how to make compost. Second, more enterprises or factories can boost local markets for produce made with compost. Third, public awareness must be improved on the quality of organic vegetables, increasing the use of compost.
Other experts say priority should be given to improved irrigation and the creation of markets for these products.
“To change from bad farming to modern farming, you need flat land, water, the proper seeds for the proper soil, and to use the same technique at the same time,” Kampong Thom Governor Nam Tom told VOA Khmer.
Kompong Thom farmers produce rice variants called Phka Romdul and Sen Pidor, two types that fit the soil and natural geography.
Meanwhile, Cambodia sells its rice products in local and international markets, including to Thailand, Vietnam and China. And countries from the Persian Gulf and Africa, such as Qatar, are now looking to buy Cambodian rice.
However, many farmers who live in remote areas remain ignorant of the long-term impacts of chemical fertilizer, and others lack technical training for the use of natural compost. Some say the use of chemical fertilizer is simply easier than the use of compost; they buy it from the market and use it right away.
There are, however, some farmers who have begun using a natural fertilizer from America called Bio1, whose representatives say it is 100 percent organic.
Preap Sy, a farmer in Kompong Trabek district, Prey Veng province, said she has been using Bio1 on her rice field for more than a year. The soil was softer and she hasn’t seen any insects eating her rice crops, she said.
“This fertilizer is really good, and if someone knows how to use it, it is even better,” she said.
Bio1 is produced in Texas and was introduced to Cambodia after researchers spent two years studying its effects on agriculture there.
Yong Sodaro, seller agent of Bio1 in Cambodia, said it has significant benefits.
“It can protect your soil from viruses,” he said. “It can eliminate all bad insects.”
A liter of Bio1 costs 123,000 riel, about $30, and is mixed with water and palm sugar.
“We use 100 liters of water mixed with 2 kilograms of palm sugar,” Yong Sodaro said. “Mix it well, and then pour in one liter of Bio1 fertilizer. After that, keep it for 48 hours and use it to spray 1 hectare of land.”
Bio1 sells well in the provinces of Prey Veng, Svay Rieng, Kampong Speu and Takeo, as well as in some rubber plantations in Kampong Cham.
However, farmer Preap Sy said some villagers still complain that it is more difficult to use than other chemical fertilizers.
“It has a good quality after testing but many farmers complained that the watery fertilizer is more difficult to spray,” she said. “They say they are lazy to do that. They want a kind of powder fertilizer, it is easier to splash into the rice field. The people said they are lazy to carry the spraying pot. As you know, we have to spray many pots in a hectare of land.”
Sin Kosal, manager of the Tapao rubber plantation in Krouch Chhmar district, Kampong Cham province, said he changed to Bio1 after using chemicals like NPK and other natural fertilizers without great results.
He tested Bio1 on three of his 2,500 hectares of plantation and saw a lot of progress.
“So I put it on the rubber plantation,” he said. “First, I put it on the young [plant]. In one month, it expanded the size of the tree, and the leaves changed color from normal. Since we’ve used it, it seems like pretty good progress.”
Sin Kosal said he was excited because the Bio1 provided more rubber.
“Because I want to have a quality harvest, and you know the latex has so many thing composed together, sugar magnesium, calcium and so on,” he said. “To have good quality latex, we also need to select fertilizer for the plantation to increase the rubber. After I used Bio1, I think it is better that using some other chemicals or natural fertilizers.”
Ung Synara, a Bio1 importer from Texas, said the fertilizer can reduce chemical fertilizer use from 75 percent to 100 percent and reduce the pesticide needed to spray for insects.
“In the areas we tested, it increased [the yield] from 1.5 tons to 3 tons of rice,” he said. “It can also protect the plants from drought for up to six weeks. It make the rice quality better, and the seed is heavier.”
Bio1 has been used in the United States, South America and Europe, he said. And it was made in a laboratory.
“It is composed of many kinds of [non-toxic ingredients] that bring the nitrogen into the soil,” he said. “It has [qualities] that activate the roots to make them receive more nutrients. Biodiversity can make the soil more moist, when prevents the plants from becoming so exhausted.”
Bio1 is a good alternative for farmers who cannot make or access locally produced compost, he said.
Cambodia uses about 2.5 million square kilometers for rice, and about the same amount again for other farming. If all farmers start to use natural fertilizer, the country could run out of resources, he said.
“For example, we use 4 tons of cow manure and chicken manure. If we all start using that, then we will start to buy or collect it, and then these resources will run out,” he said. “If we cut the bushes to produce natural fertilizer, then we won’t have very many bushes at all.”