IX, A, 1 Cox and Argiielles: Soils of Luzon 17 



have contributed material for most of the soils of the southern 

 provinces, stretches from Batangas and Laguna Provinces to 

 the extreme southeastern point of Luzon. The soils of Batangas 

 are mostly the result of disintegration of water-laid tuff, ag- 

 glomerate, etc.,^'' which extend widely over Luzon. Volcanic 

 soils are usually very fertile, and those of Batangas are no excep- 

 tion. The soils of this region are mostly loam or clayey loam, 

 but they occasionally contain a conglomerate phase. There are 

 no heavy clay soils in the whole province. Underlying the 

 surface soil in many places is undecomposed pila rock, and the 

 samples from Taal show a considerable amount of this in the 

 upper layer. The area around Batangas, which contains more 

 types of soil than any other part of this region, is made up 

 of alluvial and littoral deposits. 



Dorsey ^' has made a soil survey of the Batangas area. He 

 states that — 



Eleven types of soils of varying agricultural value and differing widely 

 in their origin and method of formation were recognized and mapped. 

 Of the alluvial soils, the Calumpang sandy loam and the Calumpang loam 

 are the most valuable for general farming purposes. Of the residual 

 soils derived in place by the slow decomposition of the underlying rocks, 

 the Lipa loam possesses the greatest natural advantages, while the Ta- 

 lumpoc clay loam is the poorest of all the soils. 



His work is the basis for fig. 1. 



The types of soils named and described by Dorsey are rep- 

 resented by our samples as follows : 



Type of soil. Sample Nos. 



(15, 16, 17, 18, 20, 21, 22, 



Ibaan clay loam |23, 24, 25, 26, 33, 34, 35, 



[36, 41, 42, 43, 44. 



Lipa 1, 2, 3, 4, 5, 6, 7, 8, 



Taysan clay 9, 10, 11, 12, 13, 14. 



Malabo waxy clay None. 



Macolod gravelly loam 31, 32. 



Talumpoc clay loam None. 



Calumpang loam 27, 28. 



Calumpang sandy loam 29, 30. 



Calumpang silt loam 37, 38. 



Muck 39. 



Salt marsh 40. 



The locations from which samples 45 to 49 were taken are 

 not shown on the map. 



Fig. 1 shows the superficial differentiation of the soils, and 

 Table II gives their chemical analyses. 



'"These have been mapped by Adams, This Journal, Sec. A (1910), 5, 57. 

 "Bull. P. I. Bur. Agr. (1903); 3, 37. 



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