By Rjay Zuriaga Castor

In Iloilo’s corn capital, aggressive corn farming and heavy herbicide use are stripping away vital watershed forests, leaving downstream communities to pay the price during devastating floods.

A harvested cornfield stretches across the rolling hills of Barangay Alapasco, Batad, Iloilo, lies largely barren after the cropping season in May 2026. (Rjay Zuriaga Castor photo)

Sixty-year-old Rona Aloadiel, a resident of Barangay Pasayan in Batad town in northern Iloilo, still mourns the Christmas Day devastation that Typhoon Ursula brought in 2019. She lost six of her loved ones, who drowned when floodwaters surged from the higher slopes of Barangay Alapasco during what should have been a festive holiday.

For locals, the tragedy was not entirely a surprise. Aloadiel said they have witnessed the steady disappearance of trees in the corn capital of Iloilo, replaced by expanding, multi-hectare farms of the crop.

“Problema kay puro na mais kag gin isprayhan pa. Dapat kahoy, prutas ang ibutang sa kabukiran kay ang mais yah ang duta naga pugday,” she said.

[The problem is our mountains are all corn now, and it’s even being sprayed with chemicals. There should be trees and fruit-bearing plants in the uplands because corn causes the soil to loosen.]

About 80% of Batad’s forest cover was lost over the past two decades, according to the town’s Comprehensive Land Use Plan (CLUP). The local government attributes the decline to kaingin or slash-and-burn farming, illegal logging, charcoal production, and, primarily, the conversion of forestlands into agricultural areas, particularly for commercial corn farming.

Data from the Municipal Agriculture Office in 2025 show that corn plantations occupy forestland areas across eight barangays.

“Generally, forested areas tend to have better water retention than barren areas, those planted with crops, as they absorb water better. This, in turn, reduces the possibility of flooding as less water runoff reaches downstream,” said Ricardo “Richie” Escanlar, a geologist from the Iloilo City government.

Much of the town’s remaining forestland lies in Barangay Alapasco, a critical watershed that serves as a vital catchment basin, eventually feeding the rivers and streams that flow down into Aloadiel’s barangay and other low-lying communities.

Salvador Manglinong, Jr., officer-in-charge of Iloilo’s Provincial Environment and Natural Resources Office (PENRO), said corn itself is not the primary problem in the forest denudation.

The real culprits are farming practices adopted by plantations to grow GMO corn, he said. They rely heavily on herbicides or chemical weed killers that non-GMO corn varieties do not require.

Herbicides worsen soil erosion and sedimentation and strip the land of its natural ability to retain water. According to Manglinong, these chemicals have also crippled the local government’s reforestation efforts.

‘Converting’ protected forestlands

Right inside Alapasco itself, hectares of corn farms are thriving on land that is officially classified as protected forest.

They operate within forestlands covered by Certificates of Stewardship Contracts (CSCs) and Community-Based Forest Management Agreements (CBFMA), tenurial agreements issued by the Iloilo PENRO of the Department of Environment and Natural Resources (DENR) in 1980 and 2005, respectively.

The agreements were designed to allow communities to use forest resources while protecting and rehabilitating public forestlands. Instead, vast stretches of forestland have been converted into corn farms.

Records of the Iloilo PENRO show that about 140 hectares of forestland are covered by CSCs awarded to 58 residents of Alapasco, Nangka, Caw-i, and Tanao.

But in Alapasco, a CBFMA covers 347.49 hectares of forestland, a massive tract of land nearly five times the size of the entire Iloilo Business Park in Iloilo City. This sprawling area already includes stewardship contracts with individual residents.

Daily Guardian sought comment from the Mapinadayunon Rural Association (MRA), the holder of the CBFMA, regarding concerns over compliance with the agreement and the presence of corn farms within the forestland. The association did not respond to requests for comment as of publication.

Cleared and cultivated slopes surround the Alapasco Small River Impounding Project in Barangay Alapasco, Batad. Alapasco hosts the largest forestland and is a major corn-producing zone of the town. (Rjay Zuriaga Castor photo)

PENRO’s Manglinong said corn cultivation is not prohibited inside CBFMA areas, provided it is integrated with trees and other vegetation as it forms part of an agroforestry system.

“They can plant corn. There is no quarrel with that. They can plant anything actually but it should be in the right way. You can always combine corn with trees. A tree takes years to grow, 5 to 10 meters and you can realize that maybe 10 years after,” Maglinong explained to Daily Guardian.

The real issue is in the farming practices, he said, which involve stripping away the natural vegetation to clear the land for corn and relying heavily on chemicals to kill weeds.

“The requirement of corn, that is where the problem starts. The lack of concern with the other plants and the focus only is on the corn and then you are willing to sacrifice other plants that are not good, it is not in accordance with the purpose of the program. Corn should be combined with other commodities,” he added.

A scanned copy of the CBFMA shows the authorized objectives and activities for which the CBFMA area should be managed, including the obligations of the DENR and Mapinadayunon Rural Association, the CBFMA holder.

Yellow corn

Batad and neighboring northern Iloilo towns rely heavily on corn for livelihood. Like the rest of the country, the fields are predominantly planted using genetically modified varieties designed to tolerate glyphosate, a broad-spectrum herbicide commonly used to control weeds.

Environmental researchers have long warned that the expansion of genetically modified corn into upland and sloping terrain can come with ecological consequences.

Studies by the farmer-scientist network MASIPAG in Lake Sebu, South Cotabato and Maayon, Capiz found that glyphosate-tolerant corn encouraged cultivation on sloping land and was associated with increased soil erosion, reduced vegetation cover, and greater movement of soil and agricultural pollutants into waterways.

A 2020 study by Dr. Fernando Siringan, a former director of the UP Marine Science Institute, linked extensive yellow corn cultivation in upland watersheds in Cagayan Valley to forest loss, erosion, river siltation, and worsening flood impacts downstream.

Escanlar said they have long warned that converting forested land into corn farms amplifies flooding risks during intense rainfall. Forested areas provide greater slope stability compared to corn-planted areas because tree roots help bind soil and reduce erosion, he said.

Melvin Purzuelo, executive director of Green Forum Panay Guimaras, Inc., said sedimentation is among the most important concerns associated with upland land conversion.

“If sedimentation continues, the storage capacity of dams, rivers, and creeks is reduced. Over time, waterways become shallower and can carry less water during heavy rains,” Purzuelo said.

The concern is particularly relevant in Alapasco, which serves as a critical watershed for the town. When the denuded upland slopes can no longer absorb the rainfall, the water rushes down, draining heavily into the Alapasco Small River Impounding Project (ASRIP).

Locals cast their fishing nets at the Alapasco Small River Impounding Project on a sunny midday, taking advantage of the man-made reservoir’s fish resources. (Rjay Zuriaga Castor photo)

Local government documents note that erosion, sedimentation, and agricultural runoff have gradually affected the reservoir’s condition over the years.

The CLUP also stressed that the bare mountain’s “reduced capacity to absorb rainwater,” leads to immediate and high-volume surface run-off during heavy rains.

It further identified this rapid runoff as a contributing factor to flash floods, including those brought by Typhoon Ursula in 2019, which killed eight people in the downstream barangay of Pasayan.

Crippling reforestation efforts

Manglinong said corn farming practices have also crippled the government’s National Greening Program (NGP) in Batad, which sought to restore degraded forestlands through tree planting and agroforestry.

He said many of the planted seedlings failed to survive as herbicide application in corn farms often killed young trees together with unwanted vegetation.

“If you want a faster [clearing] you spray herbicide, so even the trees planted for the NGP die. That is our conflict with corn. But the corn is not the culprit, the culprit there is the herbicide used,” he said.

The difficulties in sustaining planted trees, coupled with monitoring challenges during the COVID-19 pandemic, eventually contributed to the DENR-6’s decision to discontinue the NGP in the area in 2022.

A Sentinel-2 satellite image captured in April 2026 shows the mosaic of cultivated slopes and remaining forest patches surrounding Alapasco Lake in Batad. The uplands form part of a watershed that drains into low-lying communities downstream. (Satellite image courtesy of Copernicus)

The local government also reported facing similar challenges in its reforestation efforts.

Samuel B. de la Vega Jr., Batad’s Environment and Natural Resources Officer, said they have been implementing tree-growing initiatives in Alapasco since 2016, but survival rates have remained low.

“Our survival rate is low because of several factors: community acceptance, where some seedlings were killed through glyphosate spraying; weather conditions, including frequent El Niño episodes and drought since 2019; and a lack of manpower for monitoring,” De la Vega said.

Fixing land use planning

One-third of Batad’s land area is classified as flood-susceptible, but the town has not had a flood control project since 2018, based on the government’s Sumbong sa Pangulo website.

Purzuelo said engineered structures remain important in protecting communities and reducing immediate disaster impacts, although reducing flood risks in Batad will require more than engineering solutions alone.

They are often more effective when complemented by ecological measures that address the root causes of flooding, he said.

He urged the local government to bank on reforestation, agroforestry, riparian buffer restoration, and the protection of existing forest cover to provide more sustainable and cost-effective protection to communities.

Escanlar said land-use planning remains one of the most important tools for reducing environmental risks.

“From a policy standpoint, it’s much easier to manage resources and risk if the CLUP aligns more accurately with actual land use,” he said.

“I think green or nature-based and gray or human-engineered solutions can work together as long as they are planned and implemented properly,” he added.

Batad has launched fresh initiatives to pursue these measures, said de la Vega.

Among its flagship initiatives is the Batad Pocket Forest of Hope: An Arboretum of Philippine Native Trees, an arboretum launched in Alapasco in 2021 to serve as a future source of native tree seedlings for the town’s greening program, Balik Lunhaw.

Residents plant native trees near Alapasco Dam on November 23, 2021. The tree planting is part of the efforts of Batad to preserve and grow Philippine native tree species, which will then produce seed sources for the town’s future reforestation projects. (Photo courtesy of MENRO-Batad/Facebook).

The CLUP, approved in 2023, also recommends reviewing forest tenure agreements, reducing corn farming on slopes exceeding 18 percent through the enactment of ordinances regulating cultivation in forestlands, and the promotion of Sloping Agricultural Land Technology.

He said the provincial government is also pursuing the Alapasco Integrated Area Development Plan, which seeks to transform the man-made Alapasco Lake into a sustainable ecotourism destination while promoting watershed rehabilitation and environmental protection.

A wake-up call

Until these efforts show results, communities downstream continue to bear the consequences.

In Zone 3 of Barangay Bulak Sur, residents have learned to live with floodwaters that regularly cut off their households from the rest of the world.

Rogema Diel, who was born and raised in Zone 3, said a nearby stream connected to the Sibajao River Watershed swells during heavy rains, trapping them whenever water rushes over their usual crossing.

“Daw nasanay na kami nga magdalom ang tubig,” the 39-year-old native shared.

[We are already used to it every time the flood rises.]

The stream connected to the Sibajao River Watershed which serves as the only crossing for residents of Zone 3, Barangay Bulak Sur, Batad. During periods of heavy rain, the water level rises and can isolate more than a dozen households from the rest of the community. (Rjay Zuriaga Castor photo)

When the current remains manageable, residents cross together with no guide ropes and no other protection from the current.

“Pabalasbas lang kami, daw gasunod ka lang sa agos sang tubig,” she said. “Halin kami sa babaw paubos nga indi lang maanod sang tubig. Hindi man lang isa nga gatabok kami. Kinahanglan damo kami para bululigan. Kung isa ka lang, hadlok ka man basi maanod,” she added.

[We just hold on to each other and go with the flow of the water. We make sure we will not be swept away by the current. We never cross alone. We have to be in a group so we can help one another. If you’re by yourself, it’s frightening because you might get carried away by the water.]

When prolonged rains hit and the stream becomes impassable, families are forced to wait or take long detours through rice fields and around the Alapasco Dam area to reach the safe ground. There are times when it takes up to three weeks before the stream becomes safe and normal again, said Diel.

Over the years, residents have built makeshift bridges, only to watch floodwaters tear them away again and again. Their simple request for a permanent bridge is yet to materialize.

“Ang ano lang gid namun is matulayan na lang. Biskan motor lang or tawo ang makaagi,” Diel said. “Amo lang na napangayo namun.”

[All we really want is a bridge. Even if it’s only for motorcycles and pedestrians to pass through safely. That’s all we’re asking for.]

This story was supported by the Earth Journalism Network through its Extreme Weather in the Philippines Investigative Reporting Fellowship.