This research established the biophysical and socio-economic information of households in six barangays in Tarlac and four in Zambales that were covered at different depth categories. It also identified and documented existing Integrated Nutrient Management (INM) practices adopted by farmers; explored indigenous knowledge and gender-cultured management practices; determined problems on INM and sweetpotato production; compared data by province; and conducted case studies on INM farmer-practitioners.
Results showed that the covered barangays in Tarlac were mostly rainfed unlike in Zambales where majority of the farms were irrigated. Lahar deposits have sandy loam texture with depth ranging from 50 cm to more than 4 meters in flat to hilly terrains. Crops grown were rice, corn watermelon, peanut, sugarcane, yambean, cassava, amargoso, and sweetpotato.
The farmers had classified the soil into four categories and developed indicators for each. They had few superstitious beliefs on sweetpotato production and used indigenous tools, practices, methods, machines, and equipment in the various stages of their economic activities.
The sharing of work and responsibilities between men and women was evident both in farm operations and off-farm activities.
Sweetpotato remained a consistent component crop of farming systems in lahar-laden areas in Central Luzon. The lahar deposit was generally perceived as less fertile compared to the original soil but there were few respondents who perceived it to be more fertile. The best variety identified in Tarlac was VSP6 in all lahar categories, but Taiwan variety ranked first in terms of yield in Zambales.
Acidity, lack of nutrients, plenty of stones and grasses, foul odor, inadequate water and ineffective fertilizer used were the constraints identified in growing sweetpotato in the different lahar categories.
Integrated Nutrient Management and related practices such as preparation, irrigation, fertilizer application, weeding, pest management, variety and crop residue management did not vary much with the depth of lahar deposits in their farms.
Out of the 154 respondents, only 54 percent had tried INM practices either through crop residue incorporation, use of organic + inorganic fertilizer, and use of adaptable varieties and irrigation + fertilizer use. The benefits of irrigation were more striking in deeper lahar deposits while fertilization and weeding effects were the same regardless of lahar depths.
