SOILS FEKTILIZERS. 19 



contain large areas of wiud-drifted sands, broken by low flats without drainage 

 and occupied in places by alkali lakes. Although only a relatively small pro- 

 portion of the valley is now under cultivation, most of the soils are easily 

 cultivated and well adapted to grains, grasses, legumes, and certain vegetables. 

 Some of the lower lying slopes and depressions suffer from seepage water and 

 alkali. 



The agricultural possibilities of the Canal Zone. Part I, Reconnoissance 

 soil survey, II. H. Bennett ( JJ. S. Dcpt. Agr. Rpt. 9o, pp. 5-88, pis. 10, p(). I, 

 map 1). — This report which is accompanied by a paper on The Outlook for 

 Agriculture in the Canal Zone (see p. 91) discusses the region with respect 

 to physical features and area, climatic and agricultural conditions, forests, 

 soils, and irrigation. 



The soil material ranges from the fine beach sand through alluvial and col- 

 luvial clay loams of stream bottoms and lower slopes to the more predominant 

 plastic, heavy residual clays of the hills. The residual clay types cover about 

 80 per cent of the available agricultural land and are formed through the de- 

 composition in placfe of volcanic, igneous, and sedimentary rocks. The range 

 in organic matter content of the residual types in samples analyzed was from 

 1.75 to 8.30 per cent, with few below 3 per cent. The clay loams of the bottoms 

 and lower slopes contain suflScient organic matter and coarse grains to give 

 a good tilth. The sandy lands which occur exclusively as narrow coast fringes 

 consist principally of the coarser and more resistant particles of rock fragroents, 

 of stream sediments, and shore-line degradation i>roducts. 



Characteristic of the soils are the small surface accumulation of vegetable 

 mold and the strong resistance offered to erosion. The "rapid disappearance 

 of plant remains is due in a large measure to the fact that the high humidity 

 of the rainy seasons, followed by the winds of the warm dry season, favors 

 rapid disintegration and oxidation of plant remains." The resistance to erosion 

 is due to the universally low content of sand and high content of clay, coupled 

 with the fact that the soils are never loosened by freezing. The lands are 

 further assisted in holding place against wash by the dense vegetation and the 

 almost total absence of cultivation. 



Records of drainage in India, J, W. Leather {Mem. Dcpt. Agr. India, 

 Chem. Scr., 2 (W12), No. 2, pp. VIII+63-lJ,0, figs. 11; abs. in Chem. Abs., 6 

 (1912), No. 11, p. l/f87). — Studies of evaporation and of the amount, nitrate 

 content, and movement of drainage water from fallow and from cropped soils 

 at Cawnpore, 1903-1010, and at Pusa, 1906-1910, are reported. See also a 

 previous note (E. S. R., 2.3, p. 420). 



The evaporation was nearly independent of the season, whereas the drainage 

 varied with the rainfall. A good crop reduced evaporation to two-thirds or 

 one-half of that from fallow land. The amount of ammonia from both bare 

 fallow and cropped laud was as small as has been found at Rothamsted. The 

 amount of nitrate in years of good rainfall was much greater than at Rotham- 

 sted. " The amount of nitrate in drainage water from cropped land is very 

 much less than from fallow land, and there is some evidence that higher plants 

 interfere with nitrification. Nitrification has been found at Pusa to be active 

 only during wet weather and then only for a short time. The evidence of the 

 Indian records goes to show that the water descending during wet weather 

 passes very uniformly through the soil and not chiefly by means of 'larger 

 channels ' as has been commonly supposed." 



Lysimeter investigations, 1911, E. KRtJGEB (Mitt. Kaiser Wilhelms Inst. 

 Landw. Bromberg, 4 (1912), No. 2, pp. 129-133). — This is a continuation of 

 previous work (E. S. R., 25, p. 21), and reports studies on the influence of 



