CALIFORNIA CITRUS CULTURE. a) 
FERTILIZATION. 
In the young orchards—in all orchards—a winter cover crop of vetch, 
Canadian field peas, burr clover, or other vigorous legumes (vetch is 
probably the best) is very desirable. This insures against washing of 
the soil in case of heavy rainfall, supplies the needed humus, and also 
adds to the soil the most expensive, and possibly the most deficient, soil 
element—nitrogen. The roots of this cover crop also liberate other 
elements of fertility. The soil bacteria take the free nitrogen from the 
air and combine it with the soil salts, when it is in form to be utilized 
by the trees. This is emphatically the cheapest way to secure the 
valuable and greatly needed nitrogen. We must have abundant water 
for both the cover crop and the trees. This cover crop should be plowed 
under not later than February, that it may be decomposed or converted 
into humus in the early spring as the probable moisture at this season 
promotes decomposition. To plow this under at so early a date and yet 
permit the plant to reach its full development requires that the seed 
of the cover crop be planted early—not later than September. In case 
of light rainfall in the autumn irrigation must be practiced, not only 
as the seed is drilled in, but also when needed afterwards. In this case 
broad, shallow furrows must be left so that irrigation can be accom- 
plished whenever it is desired to water the plants. Some of our best 
citrus growers advocate and practice the planting of cover crops in 
summer, using at this season cowpeas. This may be wise in case one 
has abundant water, especially in a young orchard, but in this case 
we must be very careful that our trees are not robbed of the required 
amount of water. I can but believe that this is a questionable practice. 
The questionable practice of growing alfalfa in citrus groves is an 
increasing one. This makes a heavy demand on the water supply. 
Dr. E. W. Hilgard used to say that alfalfa hay was easily worth eight 
dollars per ton to plow under as a fertilizer. Dr. C. G. Hopkins main- 
tains that growing alfalfa, just to use to fertilize our orchards, is well 
- worth consideration. (See the Monthly Bulletin, Vol. I, No. 9, page 
641.) 
Many utilize the space between the young trees by growing an extra 
summer crop of some useful vegetable. In such case nothing is better 
than beans, as these tend to make the soil loose and friable, and as these 
are legumes, they really enrich the soil by adding nitrogen, as we have 
already explained. Beans are also one of our most profitable field crops. 
Many, however, grow no secondary crop, preferring to give the trees, 
old or young, all the fertility that the soil possesses. 
As the grove reaches on toward maturity the presence of abundant 
humus is more and more important, and so the cover crop must not be 
