348 HORTICULTURE [Bot. Absts. 



2347. McBeth, I. G., and J. R. Allisox. Necessity for manure standardization. Cali- 

 fornia Citrograph 4: 259, 27S. 2 fig. 1919.— The problem of maintaining the organic con- 

 tent of citrus lands would seem to be one of the biggest problems confronting the Southern 

 California citrus industry of today. The tremendous demand for manure combined with the 

 limited supply has led to excessive prices on one hand and adulteration with sand, dirt, water, 

 etc. on the other. An analytical study was made of 76 carloads bought by the Leffingwell 

 Rancho at Whittier. The results presented in a series of graphs show that there is little 

 correlation between cost and value. As a result of these studies the authors suggest the 

 following method of evaluating manures in southern California, where the phosphorus and 

 potassium content is commonly ignored. It is believed that $4 a unit for nitrogen and 5 

 cents a unit for organic matter is sufficiently high to cover the full value of the product to the 

 grower, delivered at his nearest station.—/. E. Coit. 



234S. McClelland, T. B. Terrenos productivos e improductivos de cafe. [Profitable 

 and unprofitable coffee lands.] Porto Rico Agric. Exp. Sta. Bull. 21. 15 p. PI. 1-2, 5 fig. 

 Span. Ed. 1919. [Eng. Ed. 1917.] — The hills met with in the district extending from the 

 west coast of Porto Rico well back into the interior, produce vigorous coffee trees on the 

 lower slopes, but near the top the trees are of poor growth with low yields. Studies were 

 made to find the cause of this condition. It was found that liming the soil was without 

 benefit, that the moisture content was not a contributing factor, since 0.3 per cent was the 

 average difference in moisture content of soils from the upper and lower slopes, and finally 

 frequent cultivation combined with application of animal manure failed to produce proper 

 growth on the upper slopes. It appeared that the condition was due to washing away of the 

 soil from above which is deposited on the lower slopes. The poorer areas should be devoted 

 to forest or pasture, or if coffee is to be planted large holes should be prepared and filled with 

 organic matter. — John A. Stevenson. 



2349. Miller, C. C. Injurious lemon roots. California Citrograph 4:356, 359. 2 fig. 

 1919. — It is the custom in California to grow the lemon on sour orange stock. Frequently the 

 lemon bud is placed too low, and after the soil accumulates above the bud union, some lemon 

 roots will put out. Wherever this has occurred the tree deteriorates. It appears that the 

 lemon root actually injures the tree causing the branches just above such a root to show 

 yellow leaves. When the lemon root is cut off the tree quickly recovers. — J. E. Coit. 



2350. Mitra, M. Discussion of winter pruning vs. summer pruning. Better Fruit 13 u : 

 8, 26. May, 1919.— In reply to an article in Better Fruit by C. I. Lewis, the writer discusses 

 the relation of stored carbohydrates, particularly starch, to summer and winter pruning of 

 fruit trees. Investigations with seedlings and large bearing trees have shown the disappear- 

 ance of starch from spurs and branches during the dormant season (November to March), 

 while an abundance of starch was found at this time in the main stem and roots. Beginning 

 with the growing season starch appeared again in spurs and branches and was particularly 

 plentiful around the "plant organs." Because of this cyclic movement of starch, it is pointed 

 out that pruning should be done as much as possible during the dormant period of the tree 

 and the least in summer time, thus saving the tree from an excessive loss of carbohydrates. — 

 A . E. Murneek. 



2351. Newell, Wilmox. Citrus canker eradication in the State of Florida. California 

 Citrograph 4: 313, 323, 1919.— See Bot. Absts. 3, Entry 2713. 



2352. Paddock, E. H. Bridge grafting on citrus trees. California Citrograph 4:276, 

 277. 3 fig. 1919.— Citrus trees when girdled and ruined by gum disease or pocket gophers 

 may be saved by ordinary bridge grafting. As a result of experiments it was shown that it 

 was more economical to save ;i tree by bridge grafting with sour orange wood bridges than to 

 remove the tree and grow a new one in its place. Standard bridge grafts resulted in a quicker 

 recovery than when sour orange seedlings were planted around the base of the injured tree 

 and their tops grafted into the trunk above the girdled area. — J. E. Coit. 



