158 EXPERIMENTAL FAU31S 



4-B EDWARD VII., A. 1905 



Plots C and D differed from B only in the cutting and mulching of the Hairy 

 Vetch. The crop was cut June 2 and left on the ground. From an observation made 

 shortly after the cutting, it was thought that the vetch would not produce any after- 

 math, and that it would not long survive the cutting. This proved to be the case. 

 The vetch rapidly died and its place was taken by a growth of Foxtail, &c. These facts 

 ■are indicative of the unsuitability of Hairy Vetch if it is desired to mulch. Further, 

 the data of these two plots as regards the effect of mulching on the moisture content 

 •must not in any sense be considered conclusive. 



Plot E was in clover and Timothy, sown 1903. Throughout the season it gave 

 but a ' thin stand,' the clover gradually disappearing. The dates of cutting are May 

 28, June 29, July 21, and August 17. The cut herbage was all allowed to remain as a 

 mulch, but being very light acted poorly in that capacity. 



The samples were collected every two weeks from May 9 to August 28, and were 

 taken to a depth of 14 inches. 



It will be noticed that at the outset the percentage of moisture in Plot A is con- 

 siderably lower than that of the other plots of the series. Four days previous to the 

 collection of the sample this plot had been ploughed but not disked or harrowed. This 

 neglect resulted in a most serious drying out of the soil. When soil, and especially 

 that which has been in sod, is left in ridges, the air freely circulates about and through 

 it, with the effect just noted. If moisture is to be conserved it is essential that the 

 ploughing be followed immediately by the disc and smoothing harrows. It is only thu3 

 that a fine earth mulch will be formed and evaporation checked. Although there was % 

 very fair rainfall — one above the average, indeed — for May, this plot did not equal the 

 others by several percentages until June G, so seriously had its soil been dried out 

 There is in the results of this plot during May an important lesson alike for the farmer 

 and the orchardist. 



From the fact already referred to, that the growth of Plot B was not as uniform 

 as could be wished, it may not be wise to discuss the details too closely. We had hoped 

 inferences might be drawn from its data as to the relative amount of moisture with- 

 drawn from, the soil by Hairy Vetch or conserved by the shade of its foliage. As the 

 summer may be described as both cool and wet, and as the soil was in places not 

 entirely covered with foliage, we only feel justified in saying that the data do not 

 indicate any great exhaustion by the Hairy Vetch of the soil moisture. Probably the 

 loss which would otherwise ensue from the setting up of capillarity is prevented by the 

 shade furnished by the crop, the heavy foliage, undoubtedly, would act beneficially 

 and effectively as a mulch. 



On Plot C, the crop (Hairy Vetch) was cut on June 2, and the crop left on the 

 ground. There was not, however, a sufficiency to cover tlie plot and we find that as 

 the summer advanced, moisture to some extent was lost through capillarity being 

 established. Consequently, in July the soil of this plot was drier than that of either 

 AorB. 



The growth on Plot D was very scanty, resulting in an exceedingly thin mulch 

 when cut, and we have, therefore, in the data, evidence of the drying out through 

 capillarity and evaporation, especially in the latter part of June and during July. 



The results of Plot E are similar in trend to those just considered, though showing 

 a still further exhaustion of soil moisture. This was undoubtedly due to the stronger 

 growth on Plot E, which of course, means more soil moisture lost through transpiration. 

 Our results in 1902 and 1900 showed most emphatically the great draft made by a sod 

 on the soil's moisture and the reduction to 4*7 per cent (July 18) was most assuredly 

 chiefly due to the same cause, the large amount of transpiring surface. 



