by Noel T. Provido
Huwag magpatalo sa El Niño!”
That was our country’s battle cry in 1998 when our country was hit by the wrath of El Niño.
El Niño refers to the unusual warming of sea surface temperatures along the equatorial Pacific that is usually characterized by below-average rainfall, which leads to a dry spell.
Data from the Department of Agriculture revealed that the 1998 El Niño had affected almost 74,000 hectares of agricultural lands in 18 provinces. During the first half of 1998, the country’s palay and corn production went down by 27 percent and 44 percent, respectively.
After twelve years, another El Niño episode is about to hit our country, proof that it is indeed a recurring phenomenon and the challenge for us to beat the negative impact of the forecasted prolonged dry spell remains.
One of the lessons learned during the 1998 dry spell is the need to disseminate timely information to our farmers to help them mitigate the adverse impact of El Niño to our country’s food production.
With this, the DA and other concerned agencies such as the Philippine Council for Agriculture, Forestry, and Natural Resources, Research and Development (PCARRD), the Bureau of Soils and Water Management (BSWM), Philippine Rice Research and Development Institute (PhilRice), and the Philippine Council for Marine Aquatic Research and Development (PCMARD) have identified the following technology interventions:
Small scale irrigation systems
The small-scale irrigation systems include Small Water Impoundment (SWIM) and Shallow Tube Wells (STW).
The SWIM taps surface water for agricultural use. Small water impounding projects have dam heights of not more than 30 m and/or a volume of storage not exceeding 50 million cubic meters.
The Small Farm Reservoir (SFR) is the smallest version of SWIM. Its dam height is normally below five meters. It gets water supply from rainfall and excess runoff coming from small catchments areas with no defined stream. An SFR is individually-owned and managed by farmers for irrigation, especially during dry season cropping.
STW on the other hand taps shallow ground water as source of irrigation for crops. It is reliable during dry season when surface water is limited or not available. According to DA, in Luzon , the most often observed method of drawing water from the ground is the use of centrifugal pumps primed either by diesel engines or electric motors via the drilled tubes or concrete cased open dug wells. In Nueva Ecija and Pangasinan, these are used by farmers to supplement irrigation of non-rice crops such as onion, pepper, corn, cotton, tobacco, and tomato during dry season.
Other methods
To effectively manage water supply, agricultural researchers identified other irrigation methods that have been studied and warrant further application in appropriate areas. These are:
Drip irrigation. It is one method whereby small amounts of water are applied at short intervals to the soil surface by single emission point. Hence, it enables a uniform distribution of water to all plants to the area of the roots.
Diversion dams. These are structures constructed across a channel or river to raise water level and allow diversion of water by gravity from the ground.
Intermittent irrigation-drainage water management scheme. This scheme rationalizes the utilization of limited water supply. Irrigation is provided at the time when it’s most required without causing damage to crops.
Cloud seeding. Drought situations may be abated by well-planned rain stimulation operations such as cloud seeding. This is a method of inducing rain clouds to produce rainfall. Sodium chloride or salt is dispensed to the rain-bearing clouds to coalesce with ice crystals at the right temperature and humidity. Condensation takes place in the cloud system transforming ice droplets into rain. The BSWM, in coordination with Philippine Airforce and PAGASA can undertake periodic cloud seeding.
