THE MONTHLY BULLETIN. 25 



stirred by means of cultivating implements. In experiments with the 

 two kinds of mulches it was found that the straw mulch is much more 

 efficient than the ilust muk'h as a moisture eonserver, but it was looked 

 upon as not a feasible method for large tracts of land because of the 

 expense involved in the purchase of straw end because of certain prac- 

 tical difficulties it presented in soil management for some crops which 

 are at once obvious to him who is conversant with methods of crop pro- 

 duction. From very recent experiments of fruit growers in this 

 State I am inclined to class straw mulching with dust mulching as a 

 thoroughly practicable method, and particularly for orchard conditions 

 even on a rather extensive scale. Not only can we conserve more water 

 by using the straw mulch, but we can conserve the humus of the soil 

 by decreasing the rate of oxidation of organic matter, and Ave can also 

 eliminate other mischief to the soil which constant cultivation with 

 heavy tillage implements, necessary in preserving an efficient dust 

 mulch, is bound to entail. Considering, further, that we are in part 

 at least compensated for the additional cost of the straw mulch not 

 only by water and humus conservation but l\v actual addition of humus 

 when from time to time the straw is plowed under, it is not at all 

 unlikely that under manj'' of our orchard conditions the straw mulch 

 may supersede the dust mulch in large part. The straw used should 

 preferal)ly be that from legumes, such as lima beans, and have the 

 merit of cheapness, efficiency as a water and humus eonserver and as 

 a valuable material for humus formation and nitrogen addition. While 

 bean straw has possessed all these properties in recent years, I fear that 

 in some localities its cost is ])ecoming prohibitive. 



]^ut we can always fall back on the old reliable dust mulch which 

 under all conditions is feasible and destined to remain perhaps forever 

 the most Avidely used method of mulching which we know. Without 

 going into the details of experiments carried out in this State to show 

 the proper methods and the efficiency of dust mulching, I may inform 

 you as I have said to some of you on other occasions that as between 

 three and six inch cultivation or mulch depths in our orchards the six 

 inch depth proved the more efficient ; but since its use involves certain 

 practical difficulties I recommend that at least a five-inch dust mulch be 

 maintained on the soil's surface to conserve the moisture. This dust 

 mulch must be frequently stirred if it is to act most efficiently, for even 

 in its dry and apparently fluffy state the soil material is heavy enough 

 to pack of its own weight and thus establish the passages again by 

 which water may ascend to the surface and may evaporate and be lost. 

 In experiments on this point it was found by Loughridge in this State 

 that cultivation twice a week saved the most moisture. This, however, 

 would cost too much to make the moisture conservation pay for its use. 

 Cultivation once a week, however, could be used and made to pay well 

 for the moisture thus saved. In such dry seasons as the past two have 

 been in this State moisture is the limiting factor in crop production 

 and every tenth of one per cent of it saved by cultivation means on the 

 average two tons of water saved per acre for only one foot in depth. 

 Need I emphasize more strongly the necessity of very frequent summer 

 cultivation under our orchard conditions when there can be no doubt 

 that the use of the method would have made the difference between 



