“Rice normally grows at temperatures between 20-35°C. Reports have indicated that temperatures above 35°C is critical for rice growth especially during the reproductive stage. At present, temperature may reach up to 38 to 40°C,” said Dr. Norvie Manigbas, PhilRice plant breeder.
According to studies, rice yield can decrease by 10% for each 1°C increase in minimum night temperature during the dry season.
Dr. Jasper G. Tallada, head of the Institute’s Climate Change Center said, “Drought affects all stages of rice growth. It does not only reduce water supply but also increases the amount of water needed for plant transpiration.”
For irrigated lowland, farmers may consider planting several early-maturing varieties such as PSB Rc10 (Pagsanjan), NSIC Rc130 (Tubigan 3) and NSIC Rc152 (Tubigan 10). Pagsanjan matures in 106 days with a maximum yield of 7.5t/ha. Tubigan 3 matures in 108 days with a maximum yield of 7.6t/ha while Tubigan 10 matures in 109 days with a maximum yield of 8.7t/ha.
Farmers may also plant NSIC Rc134 (Tubigan 4), an early-maturing variety (107 days) with a maximum yield of 9.8t/ha and NSIC Rc160 (Tubigan 14) also an early-maturing variety (107 days) with a maximum yield of 8.2t/ha.
For rainfed lowland, farmers may choose from NSIC Rc192 (Sahod Ulan 1), PSB Rc14 (Rio Grande), and PSB Rc68 (Sacobia). Sahod Ulan 1 matures in 106 days with a maximum yield of 5.5t/ha. Rio Grande matures in 110 days with a maximum yield of 6.1t/ha. Sacobia matures in 116 days with a maximum yield of 4.4t/ha. These varieties are also known for their drought-tolerant properties preferable in areas where El Niño is expected to hit worst.
Drought-tolerant varieties for the uplands include PSB Rc80 (Pasig), PSB Rc9 (Apo), and NSIC Rc23 (Katihan 1). Pasig can yield up to 8.7t/ha and matures in 112 days. Apo matures in 119 days with a maximum yield of 5.6 t/ha while Katihan 1 matures in 108 days with a maximum yield of 7.6t/ha.
“Use of direct seeding technologies can also help farmers cope up with El Nino so that rice plants can escape drought or heat. Direct seeded rice matures earlier by 7-10 days compared to transplanted culture due to stress during transplanting,” Manigbas said.
For water-saving technologies, PhilRice recommends the alternate wetting and drying (AWD) and low-cost drip irrigation system (LDIS) technologies.
Developed by IRRI, AWD guides farmers when to irrigate (or not) the rice field. Hence, this prevents wasteful use of water. PhilRice studies show that use of AWD also minimizes greenhouse gas emissions in paddy fields.
LDIS is also for efficient use of water and is recommended for irrigating rice-based crops.
Meanwhile, the use of fossil fuel-free technologies such as the rice hull gasifier-pump system, windmill- pump system, rice hull stove, and carbonizer lessens production cost and is environment-friendly.
The rice hull gasifier-pump system uses rice hull instead of gasoline or diesel in pumping water from the ground. It is recommended for rainfed areas where fuel expenses are high.
The wind mill-pump system is applicable in areas where wind energy is abundant.
A device called rice hull carbonizer processes the rice hull into biochar (charcoal). Aside from being used as soil conditioner, biochar is also popular as main ingredient in producing organic fertilizers, thus reducing dependence on synthetic fertilizers.
Farmers, extension workers, or anyone interested may download the information materials from the Institute’s website or contact the PhilRice Text Center (0920-911-1398).