THE MONTHLY BULLETIN. 181 



Again, in-i^ation is madr iiuiro difTiciilt by this l)ulky material on the 

 surface. The fire risk from a iiiuleh of dry material during the .summer 

 is an item not to be overlooked. With orchard.s which have been cul- 

 tivated deeply and in which the roots of the trees have penetrated to 

 considerable depth, the change from this deep cultivation to no cul- 

 tivation will und(nibtedly cause a temporary derangement in the feed- 

 ing of Die tree. This has been evidenced by certain work already done 

 at Riverside. 



Although there is much, in tlieory at least, which points to the value 

 of this system, caution should be ased in not putting in too large an 

 area to this system of mulching until more information is available. 

 It is as yet entirely in the experimental stage and should be considered 

 as such until definite experiments of some duration have been com- 

 pleted. Tliese are now under way at the station at Riverside and as 

 soon as definite infoi'mation is obtained published results of the same 

 will be available. 



To sum up these four systems, that system which employs a winter 

 cover crop and cultivation during the summer is the most likely to suit 

 all conditions of any of the systems discussed. The experiments now 

 under way certainly point to this method as one which makes for the 

 maintenance of the permanent fertility of our soil. 



This subject leads directly to a discussion of cover crops, since the 

 growth of such a crop during the winter is an important part of one 

 of the most promising systems of cultivation. A cover crop may be 

 used for several purposes. Winter cover crops were originally used 

 to prevent the washing of the soil by the winter rains and in many 

 cases these were made up of volunteer crops of bur clover, alfilaria 

 and mustard. As these crops were plowed under earlier and earlier, 

 the seed was not permitted to ripen and in a few years voluntary 

 crops became sparse and of little value. Thus it was necassary to 

 plant certain crops during the fall months which would be of rapid 

 growth and protect the surface of the soil during the winter rains. 

 The cereal crops were w^ell adapted for this purpose and were the first 

 cover crops planted in this State. They are, how^ever, heavy con- 

 sumers of water and in many cases it was impossible to get these crops 

 turned under quick enough to prevent the land drying out to such an 

 extent that plowing was practically impossible. Experience in the 

 eastern states demonstrated that clovers ahvays left the land richer 

 for the crops which followed and many who had had experience along 

 this line began experimenting with various leguminous crops to deter- 

 mine their adaptability to winter conditions. 



Growers gradually came to use leguminous crops and of these, com- 

 mon spring vetch and Canada field peas were most popular. The seed 

 of both these crops was relatively cheap and tlu> supply large. In 

 time, however, these crops began to fall off in yield and to become 

 quite uncertain, due in part at least to the serious attacks of the green 

 pea aphis, together with certain fungi which seemed to follow in the 

 wake of this pest. This decline in the value of these two plants led 

 many growers to go back to rye or barley as the winter cover crop. 

 That this was a step backward seemed evident to man.\ . aiul for the last 

 six years the station at Riverside has been attempting to find a cover 



