REPORT OF TEE CHEMIST 



133 



SESSIONAL PAPER No. 16 



THE CONTKOL OF SOIL MOISTUHE IN ORCHAED SOILS. 



EXPERIMENTS AT THE EXPERIMENTAL FARM, OTTAWA, ONT. 



Various phases of the ' cover ' crop system have been under examination for a 

 number of years past in the orchards of the Experimental Earms at Ottawa, Ont., and 

 Nappan, IST.S., the two chief points receiving attention from the Chemical Division 

 being the control of the soil's moisture throughout the spring, summer, and autumn 

 seasons, and the increase of the soil's fertility. 



These investigations have received discussion from year to year in the annual 

 report, so that it merely remains to state the nature of the work of 1905 and to con- 

 sider the results obtained. 



Two series of experiments, each comprising 3 plots, were instituted. In the first 

 series we sought to ascertain the moisture-content of soil under a thick mulch of straw 

 as compared with that of a soil constantly cultivated, and consequently covered with 

 a dry earth mulch. A plot in which the soil was left undisturbed was also included, 

 with the expectation that its moisture-content would be found to be less than that of 

 either of the mulched soils. 



The object of the second series was to learn the relative moisture-content of soil 

 carrying (a) a crop of Hairy Vetch, (h)a crop of tares, with that of a soil kept con- 

 stantly cultivated. 



This work has been, as heretofore, carried on with the advice and co-operation of 

 Mr. W. T. Macoun, Horticulturist, to whom my thanks are due for much valuable aid. 



The past summer, as regards rainfall, was characterized by an ample and well 

 distributed precipitation, and consequently the results do not show, as they do in so 

 many of our previous trials, any marked advantage accruing from cultivation. 



Series I., Plots A, B, and C. — The first collection of samples was made on June 

 5, when plot C was heavily mulched with straw. The dates of cultivation for plot A 

 were June 5, 15, 24, and 28; July 7, 22; August 4, 17 and 25; September 1, 13 and 25. 

 Plot B was left undisturbed, but as a crop of weeds appeared it was mown July 22, to 

 prevent them from going to seed. 



Series I. — Conservation of Soil moisture, C. E. E., Ottawa, Ont., 1905. 



Date of Collection. 



June 5 



„ 20 

 July 10 



M 24 

 Aug. S 



„ 21 

 Sept. 5 



„ 18 

 Oct. 2 



.. IG 



Plot A. 

 Cultivated. 



Water. 



Per cent. 



15 87 

 20-62 

 23 GO 

 18-25 

 18-84 

 17-71 

 15 07 

 15-21 

 17-81 

 19-43 



Per acre. 



Tons. Lbs. 



360 

 496 

 G55 

 426 

 443 

 410 

 339 

 342 

 414 

 4G0 



1,012 



874 

 1,578 

 1,280 

 1,269 

 1,.3S3 



217 

 1,G4S 



250 

 i,756 



Plot B. 

 Undisturbed. 



Water. 



Per cent. 



18 

 20 

 20 

 18 

 19 

 17 

 16 

 17 

 18 

 19 



-07 

 •21 

 -95 

 ■92 

 •77 

 60 

 -99 

 -52 

 •14 

 •31 



Per acre. 



Tons. Lbs. 



421 



484 

 506 

 445 

 470- 

 408 

 391 

 405 

 423 

 457 



1,132 

 131 

 975 



1,916 



1,860 

 398 

 311 



1,887 

 997 

 709 



Plot C. 



Mulched with Straw, 

 10 in. to 12 in. 



Water. 



Per cent. 



16 

 19 

 21 

 18 

 17 

 20 

 20 

 21 

 19 

 22 



•57 

 ■01 

 -31 

 -17 

 -63 

 -20 

 -52 

 -57 

 -95 

 •48 



Per acre. 



Tons. Lbs. 



379 

 448 

 530 

 424 

 409 

 486 

 493 

 525 

 476 

 554 



1,131 

 1,154 

 510 

 709 

 330 

 930 

 815 

 1,198 

 572 

 406 



* 2>Iay 1 to June 5. 



All three plots show a remarkable uniformity in moisture-content, due no doubt 

 to' the high rainfall before referred to. The effect of the straw mulch in conserving 

 moisture is, however, observable after August 21, for from that date on to the end of 

 the season the soil of plot C contained from 2 per cent to 5 per cent more moisture 

 than that of either of the other plots. On one or two dates it appears that the undis- 



