1«20] HORTICULTURE. 145 



Fertiliz»»rs for Oregon orchards (Oregon Hta. Bui. IGG {n)20), pp. .7-.}.S, /?//«. 

 5). — This bulletin contains an introchictory paper, Fertilizers for ( trej^on Or- 

 chards, by C. I. TvOwis (pp. 3-15), which briefly <liscnsses tlie general status 

 of orchard fertility in Orejion and summarizes the results of orchard fertilizer 

 studies thus far conducted at tlie station and at the branch stations, together 

 with the following two papers reporting recent results secunnl by the branch 

 stations in the Kogue River and Hood Iliver Valleys in some cooperative ex- 

 periments dealing with the use of nitrogenous fertilizers for fruit trees (E. S. R., 

 .'!."). p. 235) ; Nitrogen Fertilizers for Fruit Trees in the Rogue River Valley, 

 liy F. C. Reimer (pp. 1G-2G) ; and Recent Exi)eriments with Nitrate of Soda in 

 Hearing ()rcliai-ds in Hood River Valley, by G. G. Bro\Vn (pp. 27-^8). 



The experiments in the Rogue River Valley were conducted in pear, apple, 

 and peach orchards. Biielly summarized, soil analysis, as well as the re- 

 sults produced on yields by (he fertilizer treatments, indicated that lack of nitro- 

 gen is the limiting factor in some of the.se orchards. In the tests with apples 

 particularly, although there were variations between different varieties in re- 

 sponse to the fertilizers, the increases in the yield of fruit on all the plats 

 have been so large that even with the prevailing high cost of nitrogenous fer- 

 tilizers their use has proved very prolitable. The indications are that on 

 heavy .soils which iisually show a fair amount of nitrogen in the soil, the use 

 of commercial fi-rtilizers for fruit trees will not prove profitable at the present 

 time. Tlius far, it is still a question whether it will prove profitable to use 

 phosjihorus in addition to nitrogen in some of these orchards. The experiment 

 is being continued with a view to determining more conclusive results relative 

 to the value of both pho.sphorus and potash when used in conjunction with 

 niiri»gen. It is reconuuended that wherever fruit trees are not given entirely 

 saiislactory results, applications of either nitrate of scxla, nitrate of lime, or 

 sulphate of ammonia, be made to at least 10 typical tnn'S in the orchard to 

 determine whether nitrogen is needled. To secure quick results, an application 

 of 10 ll)s. per tree should be made in the ca.se of old apple and pear trees, and 

 3 ll)s. per trc^ in the case of large peach trees. 



The experimental work in the Hood River Valley has inclu<led, in addition 

 to a determination of the value of nitrogenous fertilizers for fruit trees, a 

 iiUu\y of tln> n-Iation of shade crops, such as clover and alfalfa to the use of 

 these fertilizers as affecting tree growth and production, together with observa- 

 tions on the l)lossoming habits and percentages of fruit .set where nitrate of 

 8iida and sulphate of ammonia have been used on Newtown and Spitzenl)erg ap- 

 ples covering a wide range of comlitions. 



The results thus far secured in this work indicate that in cases where the 

 orchards are not yielding satisfactorily nitrogen Is the Important missing ele- 

 ment. Tlie general experience has been that where more than two consiK'utive 

 heavy applications of nitrate are made, even to trees badly in need of this 

 fertilizer, color is often unduly sacrificed. On the other hand, sizes have tended 

 to run large, in some cases miduly large. The sacrifice of deep color is often 

 increased when heavy pr(ming, green manuring, exce.ssive irrigation, or culti- 

 vation aecompanies the application of nitrate. It is considered largely a prob- 

 lem fur the grower to decide how much he can afford to sacrifice in the matter 

 of color in order to obtain the increased size and cons(>quently larger yields. 



StUilies have been made in tree response under two distinctly different types 

 of .soil management: (1) Where clover was grown, pastured, and plowed under; 

 and (2) where :dfalfa has been growing for ;i number of years. Tiie few results 

 thus far si'cured are in favor of the latter system of management as far as 

 color in the tspitzenberg is concerned, and it appears that the use of a small 



