812 EXPEEIMENT STATION EECORD. 



problem for the expert is to compare soils and, therefore, the chances of success 

 are greatest when a soil survey has been made or when some similar soil has 

 been under proper field experiment. . . . The farmer must . . . arrange to go 

 over the land with the expert and discuss on the spot the various points on 

 which information is desired ; the necessary samples can then be drawn with 

 the proper tools and with all due precautions. . . . When no satisfactory 

 standards exist and where the expert has not made a personal inspection, so 

 much balancing of probabilities has to be done that no expert can give more 

 than a general opinion." 



Soils of Pennsylvania, F. Menges {Penn. Dept. Agr. Buls. 250 (1914), pp. 

 II-\-Jt81, pis. 8; 251 (1914), pp. 285, pis. 8). — This is a popular report on the soils 

 of Pennsylvania, consisting chiefly of a discussion by townships of the origin and 

 capacity of the soils in the State, together with suggestions as to their adapta- 

 tion to different crops. It was thought advisable to undertake the general sur- 

 vey upon which this report is based because of the great variety and wide diver- 

 sity of the soil formations of the State and the necessarily limited extent of the 

 surveys made by the Bureau of Soils of this Department. 



The soils of the Hawaiian Islands, W. P. Kelley, W. McGeoege, and Alice 

 R. Thompson {Hatvaii Sta. Bui. 40 {1915), pp. 35). — This bulletin discusses 

 briefly the general properties of the soils of the Hawaiian Islands and points 

 out the practical bearings of the investigations (E. S. R., 27, pp. 118, 842; 30, 

 pp. 419, 420; 31, pp. 11, 723; 32, p. 719; 33, p. 122) that have been made on 

 them, especially on the upland soils above the sugar belt. 



Hawaii is characterized by a rolling topography, and in almost every section 

 the arable land is broken up by gulches or deep ravines. Owing to the very 

 diverse character of the soils, " the methods of classification and mapping usu- 

 ally employed in soil surveys are not adapted to Hawaiian conditions, and noth- 

 ing less than a systematic sampling of almost every acre will suffice to give an 

 accurate idea of the location of all soil types." 



The soils are lateritic in nature, range from 6 in. to many feet in depth, and, 

 with the exception of small areas near the sea, have been formed from the dis- 

 integration products of basaltic lava. They are, therefore, highly ferruginous 

 and basic. Unusual types of soil also occur on the islands, there being on Oahu 

 highly manganiferous and titaniferous soils. Much of the soil at lower eleva- 

 tions has been formed by sedimentation and erosion from higher elevations. 

 "After a few years of cultivation, but little demarcation between the soil and 

 the subsoil is left except in locations of heavy rainfall. The humus content in 

 passing downward decreases slowly, but the fertility in the drier sections is 

 not greatly different for many feet below the surface. ... No injurious effects, 

 such as commonly follow the turning up of inert subsoil, are produced in the 

 drier sections by plowing to the depth of 30 in." 



The soils, in general, are divided, as regards mechanical composition, into clay, 

 silt, sandy, and humus soils, the clay type predominating. The predominant 

 color is red. " The potash content, on the whole, is rather below the average, but 

 frequently it is relatively more soluble than usual and consequently more avail- 

 able. • It is also more constant in different sections of the islands than any other 

 of the so-called plant-food constituents. Phosphoric acid is comparatively abun- 

 dant, but there is a wide range of variation in the percentages present. . . . 

 Notwithstanding the high percentages of phosphoric acid in Hawaiian soils, the 

 availability is, on the whole, rather low, and phosphate fertilization is neces- 

 sary in most instances except where the humus content is high. . . . The 

 humus content is high as compared with mainland .soils, and consequently the 

 nitrogen is also high, but its availability Is low, due to poor aeration. . . . Not- 

 withstanding the highly basic character of Hawaiian soils, they generally give 



