by Melody M. Aguiba
August 19, 2014
The International Rice Research Institute (IRRI) is expanding use of alternate wetting and drying (AWD) technology among Angat farmers to help cut irrigation expense and reduce emission of methane to the environment.
The practice of withholding irrigation for rice farms at certain stages has been proven to significantly cut farmers’ water use by up to 30 percent.
Farmers around the Angat area in Bulacan should take advantage of AWD as they experience water dearth.
“They get less and less water, so farmers have the interest to save water,” said IRRI Climate Change Head Reiner Wasman in a climate change workshop.
Angat water’s priority is for household use, for drinking.
As climate change worsens, manifested in increased occurrence and intensity of drought, irrigation for rice farming will have to compete with other uses of Angat water. That also includes power generation.
As another benefit, AWD enhances ecological balance.
“Flooded rice emits greenhouse gas methane. It develops when we have organic material in the soil, but no oxygen. AWD allows air to get into the soil. You don’t get methane formation,” said Wasman.
Some farmers in continuously irrigated areas like those in Nueva Ecija may not find removal of water cost-efficient.
“It doesn’t work in places where people are directly connected to canals like in Nueva Ecija,” said Wasman.
Farmers pay a fixed price of around P2,500 per hectare for irrigation fee in National Irrigation Administration (NIA) areas, whether they use water measly or not.
But some farmers in Tarlac who are trying to save on pumping water may also find AWD beneficial.
In AWD, rice farms are only irrigated every two weeks. Fields are not constantly flooded. A pipe is inserted into the ground from which to determine whether soil moisture is depleted and would need irrigation.
AWD will also be suitable in Bohol where there is a modern irrigation facility.
“In Bohol, they can just push button to turn irrigation on, so they can enforce AWD.”
IRRI may also work in rain-fed or upland areas where water is pumped, carrying diesel costs. Supply of water may also be less for those at the tailend of the dam, making them apt for AWD.
As AWD is cost-saving and reduces greenhouse gas emission, the national government may find it advantageous to modernize irrigation facilities.
“Irrigation facilities in the Philippines are not in good shape. AWD may give stimulus to improve irrigation.”
Organizations may also eye accessing a funding facility called Nationally Appropriate Mitigation Action (NAMA). It involves a financing mechanism agreed by the United Nations Climate Change Conference in Bali in December 2007.
“If you have money from NAMA you could improve irrigation facilities like they did in Bohol and enforce AWD. You have a way for mitigating emission and start co-benefits in rural areas.”
There are now countries that take advantage of NAMA as a funding source including China, Brazil, India.
Varieties with less resistance to lodging would also do well in AWD areas. When rice plants that are mature for harvest or nearing maturity fall to the ground during typhoons, and the soil is wet, these may render themselves unsuitable for milling.
Source: Manila Bulletin