THE MONTHLY BULLETIN. 163 



nitrate of lime, and no question oi' injury from the use of these has yet 

 been raised. 



A factor of great practical importance is found in the pos-sihility of 

 nsing sneli liome e'rown products as alfalfa hay, ])ean straw, and the like. 

 These materials are rich in nitrogen, and in usinj? them the grower is 

 also adding large quantities of organic matter as well as small quantities 

 of phosphorus, i)otash, and other desirable elements in about the pro- 

 portion usually lUH'ded by plants. When such materials can be obtained 

 at a fairly reasonable price, the value of the nitrogen in them alone 

 Avonld justify their use. As an illustration, alfalfa hay, air-dried, 

 usually contains about 2.25 per cent of nitrogen, so that at $8.00 per 

 ton one would pay but $3.55 per unit of nitrogen, which is much 

 cheaper than it can be obtained from most sources. The same is also 

 true of bean straw. 



Now, you may ask as to the availability of alfalfa hay when used 

 as a manure. AVhat I can say regarding this, I take entirely second- 

 hand from Doctors Kelley and McBeth, but nevertheless they will 

 pardon me. I understand from these gentlemen that when hay of 

 this kind is plowed under it becomes available very quickly, beginning 

 to be available ordinarily within two or three weeks after the time of 

 plowing under, and certain it is that it becomes available very shortly, 

 as is shown by the increased growth of weeds and cover crops. 



No special statement need be made regarding the use of all stable 

 manure available. There is apparently no better material to use in an 

 orange grove in California. Those of us who have come from Florida 

 would question the advisability of using stable manure because in 

 Florida stable manure produces die-back, and we have seen it thrown 

 away rather than made use of on an orange grove. However, when it 

 comes to California, we know by long experience that the best trees 

 are produced near the stables, and apparently we can not get too much 

 stable manure to give good results. It goes without saying here, so 

 far as stable manure is concerned, that there is nothing better. The 

 only difficulty is that there is not enough produced to serve our pur- 

 poses. 



The general use of home-produced materials, such as the above, will 

 add greatly to the wealth of California products, and where they give 

 equally good results their use is certainly to be encouraged. Doubtless 

 millions of dollars have been expended for imported materials that 

 might more profitably have been expended for home products and have 

 assisted in building up our own industries. 



Phosphoric acid, which is a principal ingredient in all of our fertil- 

 izers, has in some experiments given indication of increasing the yields 

 slightly, but its importance is not so clearly evident as that of nitrogen. 

 It would seem, however, that the application of some phosphorus will 

 prove of practical value. The coinparative value of raw rock pho.sphate 

 and superphosphate has not yet been fully determined. 



In times past large quantities of potash have been used in fertilizing 

 orange groves, the sulphate of potash being almost universally used. 

 In the experiments at the Citrus Experiment Station three plats treated 

 with potash for nine years have given an average yield little, if any, 

 larger than three similar plats to which no fertilizer was added. The 

 indications at present are that the addition of potash as a fertilizer is 

 of doubtful value. 



