The soils of Pampanga are generally of recent all north and northwest of San Fernando consist of coa southeast, silt loam to clay.
Pampanga's surface soils are composed of 54% sand, 21 % silt and 25% clay. They are slightly acidic with the exception of the Arayat sandy clay loam which is somewhat alkaline. Also, they are not sticky and plastic because the magnesium content is very much lower than half of the calcium content. The presence of high ration of magnesium to calcium indicates the degree of stickiness or plasticity of a soil.
Forestland covers 24.38% of the total land area or approximately 53,156 hectares. The Arayat National Park covers approximately 3,718 hectares, 508.69 hectares of which consists the park resort area.
Numerous rivers drain Pampanga. The largest and longest of these is Pampanga River which runs from Nueva Ecija and flows along the slope of Mt. Arayat, cutting across the entire eastern section of the province until it reaches Manila Bay. Other rivers worth mentioning are the Porac River, Gumain River and Caulaman River. These flow from streams and small inlets from the mountainous regions along the boundary of Zambales and empty out into small tributaries eventually, finding their way into the sea.
The province's source of water for domestic use is from its enormous groundwater reserves. It can be extracted through the construction wells equipped with pumps or available springwater.
Pampanga province was observed to have metallic deposits of gold, silver and copper and non-metallic deposits of clay, sand and gravel.
3.1 Gold and silver were explored, extracted and developed from the porphyritic quartz bearing andesite in Sitio La Kalyusan, Pabanlag, Floridablanca.
Copper was also explored in Pio and Planas, Porac. This metallic element is important as coen zyme needed to activate several plant enzymes. It is used in fertilizer manufacture and is effec tive when applied to neutral or acidic soils.
3.2 Non-metallic Minerals
Deposits of red-burning clays were seen in San Luis, Candaba and vicinity. Other clay deposits are also present in Sta. Ana and its surrounding areas. The indication of clay is the presence of manganese traces mixed with pyrolytic form of iron oxide. Very plastic brown clay deposit was also observed in San Fernando, San Matias, Mexico and in the municipality of Bacolor.
The most prominent non-metallic mineral deposit that was encountered was the quarry deposit of sand and gravel.
The thick, loose consolidated gravel and sand were found in the southwestern part of Angeles City and vicinity of Porac particularly the Abacan and Pasig-Potrero Rivers which may be the result of previous eruption of Mt. Pinatubo.
Other quarry deposits that can be found along major drainage of the Gumain River are sand and gravel which are good concrete aggregate due to their quartz and feldspar contents.