The weathering of rocks plays a role in a number of important environmental processes [1] to clay, silt and sand and these minerals are important components of soil in earth. Many types of microorganisms are known to inhabit soil, especially Prime Archives in Biosciences 2 www.videleaf.com rhizosphere and they play an important role in plant growth and (plant) development. In fact, these sources constitute the biggest reservoirs of P and K in soil under appropriate conditions they can be solubilized and become available for plants [2]. The Mekong Delta occupies 2.9 M (million) ha (12% of the Vietnam’s total land area) and this delta is one of the two principal areas of rice production of Vietnam. About 35% of the Mekong Delta is alluvial soil, covering 1.1 million ha along the rivers with most of the remainder acid sulfate clay soil (1.6 million ha). Both the acid and alluvial soils are deficient in phosphorus since P generally reacts with aluminium and iron under low pH conditions and forms insoluble compounds [3]. In Vietnam, granitoit distrubuted very popularly, they occupied 90% in magma rock. They distributed mainly at (in/across) East-Northern region (Song Chay, Biooc, Cho Chu, Nui La), at West-Northern region (Ca Vinh, Po Sen, Đien Bien Phu, Fanxipan), Middle region (Hai Van, Kong Tum, Song Chu – Ban Chieng), Southern region and South Middle region (Dai Loc, Chu Lai, Deo Ca, Dinh Quan, Ankroet), West Southern region (That son, Nui Sam, Hon Dat) and (granitoit in West Southern region) (this) is a valuable resource for farmers at the Mekong Delta, Vietnam, With 3 rock granite mountains (That son, Sap mountain, Ba Hon), they only have been exploited for tourisms and temples and they have not used in agricultural production. In three sites (in Mekong Delta), 137 weathered material/rock samples were collected to isolated on Alexandrov medilum and 392 P-K solubilizing bacterial isolates were isolated and stored at -20oC. There are 43 among 392 isolates had high ability of phosphate and potassium solubilization (they consisted of) including 13 strains of Bacilli and 30 strains were Proteobacteria. Some good phosphate- and potassium- solubilizing bacteria strains were evaluated their effects on many kinds of crop, (the result) showed that they saved 25% amount of PK chemical fertilizers in comparison to (the) control. Prime Archives in Biosciences 3 www.videleaf.com Twelve P-K solubilizing bacterial strains are PGPR which they have characteristics as nitrogen fixation, phosphate and potassiun solubilization, increasing concentration of nitrogen chemical fertilizer applied to vegetable led to increase nitrate concentration in leaf of Brassica juncea and Acinetobacter calcoaceticus NT30 strain suggest to use in biofertilizer production for leaf-eating vegetable nearly in the future. Keywords Bacilli; Kinds of Crop; Rock Granite Mountains; P-K Solubilizing Bacterial Strains; Proteobacteria; Weathered Rock