RTTRAT. ENGTNRKRTNO. 881 



RURAL ENGINEERING. 



Studies on the irrigation of Jauja, D. Baluizan (liol. Miii. Fomento 

 [Pent], Dir. OhruK Pub., .i (J!l(l(i}, Xo. L pp. 61, figs. 11. df/in. /).— These studies 

 have been carried on in the valley of Jauja. which is traversed by the Mantaro 

 River, but laclcs the necessary precii)itati()n to render tli(> soil productive. 



To snpitly ."t.Ndd hectares of lliese l.inds witli wiiler niid lo provide water for 

 (lie nunucii)al and household purposes of the city of .I.nn.ja. with a probahl(> popu- 

 lation of 1().0()(» people, a canal is proposed which will divei't 4,(KI() liters per 

 second from the Mantaro Kiver and carry it to the vicinity of .Tauja. The 

 lenj,'th of the canil will be 21.9 kilometers, and it will have a {jjrade varyinj; 

 from 1 meter in l.OOO in tnniiels and rock cuts to 2 per l.OOO in the agueducts 

 and from 0.8 to O..". ])er l.ood in the earth sections. Cross sections of the canal 

 in various kinds ul' ninterial ;ire shown, Bazin's fornuila havini; been used in 

 (he deternunation of the area of cross section. 



The distribution of water by measurement | R. G. Kennedy], {[Proc. 

 Iiri(/. Vonfcrciicc. tSiiiiJa. liioli. I. pp. I.l'i-13i)). — The disadvantages of the usual 

 distribution of water accordinj; to area are cited and the proposed distribution 

 iiy measure with its advantaj^es and difficulties is discussed. The system of dis- 

 tribution and assessment by volume where the user is charged according to the 

 lunnber of acre-feet actnally used is considei«ed inapplical)le in India, except in 

 tliose cases where the water is distribtited over a comparatively small and com- 

 I)act area situated in close proximity to the source of supi>Iy. 



The " module system " is described as a system in which the cultivator pays 

 ii fixed rate for the volume of water allowed to pass through a sluice at pre- 

 scribed intervals of time in sufticient quantity to mature the crop, the discharge 

 of the sluice bearing a certain proportion to the area to be irrigated. By this 

 system the charges during rainy seasons would be the same as during dry 

 •seasons. The module system is undeveloped, owing to the difficulties in devising 

 modules, arranging a scale of charges, and overcoming the in-ejudices of ir- 

 rigators. 



Contributions from the agricultural experiment station of the University 

 of Gottingen, von Seei.hokst {Jinir. Ldiulir., o.'i iUKKI). So. .'/, pp. ■iLi-J'/J, 

 /lis. 2). — From the experiments conducted on the relation between water evapo- 

 ration and drainage in fallow soils, a table has been constructed from which 

 tile following conclusions are derived : 



" In general, sandy soils give a greater (luantity of drainage water for the 

 same precii)itatiou that do loam soils. Only in .Tune and .Tuly of 190.5 and in 

 February of 190(5 was the reverse true. 



"Evaporation is always greater from a lo.im than from a sandy soil, which 

 is due usually to the greater impermeability of the former to rain and its 

 greater capillarity, which brings the water to the surface more readily in dry 

 weather." 



Further experiments li.ive l>een carried on in the use of water tipon rye, 

 barley, wheat, and potatoes, the crops being grown in tanks and the amount 

 of water actually u-ed by the plant being computed from the amount of water 

 received Iiy rainfall after deductions are made for evaporation and drainage. 

 I'our tanks were employed with the loam soils, in three of which wheat, rye, 

 and potatoes were grown with the remaining tank left fallow. The weights of 

 the tanks were taken at freqnent intervals. In computing the amount used 

 by the plants it was fi.nnd necessai'y to cstimnte the amount evaporated by the 

 soil, since it was assumed that the evaporation from the fallow soil surface 

 would not be the same as from the soil siu'face shaded by plants. 



The results of the experiments indicate that on a loam soil wheat re(iuires 



