Provincial agriculturist Jose Almedares said this finding is based on a study made by the Bureau of Soil and Water Management, although he added that the problem was noted about five years ago.
Tagged as critical areas are the towns of Natividad, Tayug, Laoac, Balungao, Sta. Barbara, Basista, Urbiztondo, Bayambang, Binmaley, Labrador, Burgos and Bolinao.
Almedares said they applied zinc sulfate by as much as 20 kilos per hectare to solve the problem, although only five kilos must be applied.
Tagged as "medium" zinc-deficient areas are the cities of Alaminos and Urdaneta and the towns of Villasis, Rosales, Sta. Maria, Malasiqui, Bugallon, Aguilar, Mangatarem, Infanta, Agno, and Mabini.
Almendares said they applied 10 kilos of zinc sulfate per hectare in farmlands in Dasol, Anda, San Nicolas, San Quintin, and Umingan.
Those with manageable low zinc levels are ricelands in San Manuel, Asingan, San Fabian, Manaoag, Alcala, Bautista and Mapandan towns.
Almendares said zinc deficiency happens in areas along the Agno River basin where farmers plant palay thrice a year.
He advised farmers in these areas to observe a gap in their planting seasons to allow their land to "rest," and cultivate high-value crops between the wet and dry seasons.
When palay is continuously planted, Almendares said ricefields are submerged in water, thus increasing organic matter while lowering micro-nutrients.
This results in an imbalance of nutrients, with the pinnacle not coming out and the leaves getting spots, he said.
Upland areas, such as in Bolinao, Anda and Infanta, become zinc-deficient due to the continuous application of inorganic fertilizer, he said.
He said zinc deficiency stunts the growth of palay, leaving it with reddish leaves.
Almendares said they are trying to address the problem through a comprehensive analysis and techno-demo solutions by applying the required amount of zinc sulfate in the affected areas.
Zinc sulfate is imported from India and Japan. It is sold at P25 per kilo.