Scientific Agriculture. 



450 



[May, 1909. 



ally find that the soil in which they 

 grow is underlaid by slate or shale 

 standing on edge, into the crevices of 

 which the roots penetrate, wedging them 

 open; while themselves flattening out, 

 and thus penetrating to moisture at 

 considerable depths. The same may be 

 observed in the case of the erect "bed- 

 rock" or foothill slates of the Sierra, 

 on which native as well as fruit trees 

 flourish in very shallow soils, some- 

 times reaching permanent moisture at 

 the depth of ten or more feet below 

 the surface. It can readily be observed 

 during rains that there is comparatively 

 little run-off from the surface of these 

 lan< s underlaid by vertical shales. 



On the same principle, the grape 

 vines which bear some of the choicest 

 raisins of Malaga on the arid eoastward 

 slopes, are made to supply themselves 

 with moisture, without irrigation, by 

 opening around them large, funnel- 

 shaped pits, which remain open ra winter 

 so as to catch the rain, causing it to 

 penetrate downward along the tap-root 

 of the vine, in clay shale quite similar 

 to that of the California Coast ranges, 

 and like this latter, almost vertically 

 on edge. Yet on these same slopes 



scarcely any natural vegetation now 

 finds a foothold. 



Similarly the "ryots" of parts of India 

 water their crops by applying to each 

 plant immediately around the stem such 

 scanty measure of the precious fluid as 

 they have taken from wells, often of 

 considerable depths, which form their 

 only source of water-supply. Perhaps 

 in imitation of these, an industrious 

 farmer has practised a similar system 

 on the high benches of Kern River, and 

 has successfully grown excellent fruit 

 for years, on land that originally would 

 grow nothing but cactus. Sub-irri- 

 gation from pipes has been applied in 

 a similar manner. 



The principle flowing from the above is 

 simply that the most economical mode 

 of using irrigation water is to put it 

 " where it will do the most good," close 

 to the stem of the plant or trunk of 

 the tree, and let it soak downward so as 

 to form a moist path for the roots to 

 follow to the greatest possible depth. 

 It is this deep penetration to natural 

 moisture, as a matter of fact, which 

 enables the small quantities supplied to 

 produce such marked effects. 



(To be continued.) 



MISCELLANEOUS. 



LITERATURE OF ECONOMIC 

 BOTANY AND AGRICULTURE. 



Cacao.— General. 



Le cacaoyer au Congo f rancais. Bull. 



Jard. Col. May 1900, p. 390. 

 Greshoff, Aantekening over Cacao- 



Kiemeu. Ind. Merc. 18. 9. 1906, p. 



635. 



Eutretieu des cacaoyeres. Bull. 



Jard. Col. Mar. 1906, p. 227. 

 Les varieties et especes de cacaos cul- 



tivees. Journ. d'Agr. trop. 1906, 



p, 76. 



Chalot et Lun. Le cacao au Congo 



fran^ais. Paris, 1906. 

 Kakaomarkt in den Niederlanden 



im Jahre 1905. Tropenpfl. 1906, p. 539. 

 See monthly market reports in Trop. 

 Life. 



The manuring of cacao. Trop. Lite, 



May 1906, p. 73. 

 Sur quelques conditions de succes 



d'un cacaoyere, Journ. d'Agr. trop. 



Feb. 1906, p. 39. 

 Wright. The cultivation of cacao 



in Ceylon. "T.A."July, 1906, p. 



73 et. seg. 



Report on cacao and cola industries 

 in the Gold Coast. " T.A." Aug, 

 1906, p. 116. 



Welternte und Weltverbrauch von 

 Kakao, 1901-4. Gordian, 20, Ic. 1905, 

 p. 251. do. 1905-6, do. 20/12/06, 938. 



The world's cacao crops and consump- 

 tion 1901-4. "T.A" Mar. 1906, p. 170. 



Kakao-produktion und Konsum, 

 Tropenpfl. 1907, p. 33. 



Cacao improvement. Hart. Tim. 

 Bull, Jan. 1907, p. 182. , „ , 



San Thome Kakao. Gordian. 8. 1 

 1907, p. 959. 



Samoa Kakao. do. 5. 8. 1906, p. 710. 



Dentschlands ein— und Ausfuhr an 

 Kakao. Tropenpfl. Aug. 1907, p. 



A review of the cacao trade. "T.A." 



June 1907, p. 359. 

 Cacao cultivation in West Africa. 



Agr. News, Aug. 1907, p. 254. 

 Cacao cultivation in West Africa 



and elsewhere. Trop. Life, Aug. 



1907, p. 116. . _ _ . 



Cacao cultivation in Uganda. Agr. 



News, June 1907, p. 202. 

 Cacao cultivation in St. Vincent. 



Agr. News, July 1907, p. 213. ■■ 

 The cacao situation. "T.A." Oct. 



1907, p. 279. 

 The shortage of raw cacao. Trop. 



Life, Nov. 190~ ■>. 169. 

 Cacao in Eucador. " T.A." Apr. 1908, 



p. 317. 



