978 



From 1903 to 1915 Java exported 598846 in\ oontaiiiiug 1083743 

 kg. of phosphoric acid, which signifies an animal loss of 83365 kg,, 

 a tritle, indeed, as compared with the enormons quantities discliarged 

 into the sea with the silt of rivers'). 



As observed before the teak-tree requires much phosphoric acid. 

 Contrariwise it thrives on any soil whatever — as far as its chem- 

 ical composition is concerned '). With a view to the calcareous 

 secretion it was obviously supposed tliat the appearance of djati- 

 kapur was associated with the nature of (he soil. Thomas Horsfuld, 

 who was the first to discuss this point, thought that the poor lime- 

 containing territories yielded the best trees, whereas djati-kapur is 

 more often found in the fertile districts*). 



This view is supported by what W. J. Spaan wrote concerning 

 the forests of Puger (resid. of Besuki): "Tfiere it appeared that 

 djati-kapur, with a very high lime-content, occurred in large quan- 



^) Reliable data we have none, and they will not be at our disposal within a 

 near date. The following, however, tends to show what quantities of phosphoric 

 acid are concerned. According to L. Ruttkn about 960ü,()0(),()00 kg . of silt are 

 transported anually from the Seiajuterritory in the island of Java (^Over denudatie- 

 snelheid op Java. Verslag gewone Verg. Wis- en Naluurk. Afdeeling K. Akad. v. 

 Wet. 26. Amsterdam 1917/18, p. 930 table). According to Jul. C. Mohr (Over 

 het Slibbezwaar van eenige rivieren in het Scrajudal. Meded. uitgaande van het 

 Dep. van tiandbouw N". 5. Batavia 1908, p. 79) the average content of F-0» in 

 this silt is 0,753",), so that every year 72,288000 kg. of phosphoric acid is taken 

 from the said teriiloiy, which means 267,7 kg. per H.A. Compared with this 

 amount the loss of the grounds of the djaliwoods in conse(juence of the withdrawal 

 of 1,72 kg. of wood per H.A. is trifling. The loss of phosphoric acid resulting 

 from the denudation process is only a seeming loss, since the silt, which is richer 

 in P-0'^ than the primitive rocks and is transported to the sawahs by means of 

 irrigationvvorks, imparts P-0-^ to the grounds and thus makes them ric^her. (L. G. 

 DEN BiORGEB, Landbouwscheikuudige ontlerzoekingeii omtrent irrigatie op Java. 

 Delft 1917. Proefschrift, p. 82, 83, 97. 98). in the Kali Samiran for instance they 

 found: sill 0.(\5]. 0,055, 0,043, 0,048 'V,, of P^O' (p. 82i; on the other hand in 

 the ground of Bolgi only 0,022 and of Kolpandjong 017 "o of P^O'' (p. 85), the 

 water of that river contains only traces. 



Seraju-territory + 2700 km^., Java ± 125,500 km^., so that the annual loss 

 will be 2621,534815 kg. of PSQ^. 



*) Much more selective is Tectona with regard to the physical condition of the 

 soil. It requires as Brandts positively says "perfect drainage and dry subsoil" 

 {I.e. p. 358). 



The withdrawal of phosphoric acid from the soil of Java is enormous in relation 

 to those in temperate climates. The Elbe in Bohemia e.g. withdraws yearly IV2 

 million kg. of P^O" according to Breitenlohner (Verhandlg. k. k. geolog. Reichs- 

 anst. Wien 1878, p. 175), which signifies a loss of only 0,031 kg. per H.A. 



») G. L. Blume, I.e. p. 44. 



