340 EXPERIMENT STATION RECORD. [Vol.43 



Rodent protection for fruit trees (Mo. Bui. Ohio Sta., 5 (1920), No. 4, pp. 

 125-127, figs. 2). — Directions are given for the protection of fruit trees from 

 mice and rabbits, and the method of bridge grafting girdled trees is described. 



Dust spraying, H. A. Gossard (Mo. BuJ. Ohio Sta., 5 (1920), No. 5, pp. 147- 

 153). — Data are given on some comparative tests of dusting and spraying apples 

 conducted during the three seasons 1916-1918. The results, although not 

 conclusive, indicate in general that spraying is somewhat more efficient than 

 dusting, but tliat dust may be advantageously substituted for some of the spray 

 applications on large orchards where time and labor are important factors. 



Culture and feeding of the apple orchard, F. H. Ballou and I. P. Lewis 

 (Mo. Bui. Ohio Sta., 5 (1920), No. 2, pp. 42-^8, figs. 4).— A comparison of fer- 

 tilizers with grass mulch and with tillage in apple growing, based on the results 

 of a 5-year experiment recently completed by the station. 



In this experiment, which was begun in a practically abandoned Rome Beauty 

 orchard 20 years old, the average cost of the tillage-cover-crop method of cul- 

 ture was $17.09 per acre per year. This included annual plowing or disking, 

 cultivation, seed, and seeding. Soy beans were used as the cover crop. The 

 grass mulch method of culture cost only $2.65 per acre per year. It consisted 

 merely of two clippings of the grass during each growing season, and the neces- 

 sary trimming, with a scythe, of small areas inaccessible to the mowing ma- 

 chine. The combined cost of the grass-mulch system of culture and of fertiliza- 

 tion in connection with nitrate of soda and acid phosphate at the rate of 5 lbs. 

 of each per tree or 200 lbs. per acre per year, even at prices prevailing during 

 the war, was slightly less than the cost of the tillage-cover-crop plan without 

 fertilization. 



With the above rate of fertilization, the grass mulch plats gave an average 

 gain of 22.2 bbls. of apples, or a net cash gain of $71.48, per acre per year over 

 the unfertilized tillage-cover-crop plats. When both the grass mulch plats and 

 the tillage-cover-crop plats were given 5 lbs. of nitrate of soda and 5 lbs. of acid 

 phosphate per tree, the grass mulch plats still gave a gain of 1.9 bbls., amount- 

 ing to a cash gain of $20.52 per acre per year, over similarly fertilized tillage- 

 cover-crop plats. 



Fertilization with nitrogenous plant food in the tillage-cover-crop plats gave a 

 gain over no fertilization of 20.3 bbls., or a net cash gain of $.50.96. per acre 

 per year. Unfertilized tillage-cover crop plats gave an average gain of 15.6 

 bbls., or a cash gain of $35.48, per acre per year over the unfertilized grass 

 mulch plats. 



On the grass mulch plats fertilization with nitrogenous plant food gave a gain 

 of 37.8 bbls., or a net cash gain of $106.96, per acre per year over no fertiliza- 

 tion on similar plats. The results were practically the same where the fertilizer 

 was applied in circles under the outer extremities of the branches of tlie trees, 

 or over the entire tree squares of ground. Distributing the fertilizer all over, 

 however, had the added advantage of improving the growth of grass. This 

 amounted to 1,650 lbs. per acre per year, sun-dry weight, as compared with the 

 grass yield of unfertilized plats. 



In a separate orchard of somewhat larger trees, wholly cared for by the 

 grass mulch method, several combinations of chemical plant food were compared 

 with no fertilization. The yields of apples per acre per year were for the un- 

 fertilized or check plats 36.7 bbls. ; for a plat which received 5 lbs. each of 

 nitrate of .soda and acid phosphate, applied on a mulch of straw maintained in 

 circular form under the outer extremities of the branches of the trees, 117.4 

 bbls. ; for a plat fertilized with 2.5 lbs. of nitrate of soda and 5 lbs. of acid 

 phosphate annually per tree, 93.4 bbls. ; and for a plat fertilized annually with 



