336 



EXPERIMENT STATION RECORD. 



[Vol. 43 



of fertilization and the average yield for the 5-year period are shown in the 

 following table : 



Fcrtilizcrfi applicil and the 5-year average yield per acre in an experiment 

 iiith sweet potatoes, 1'J15-1'J1D. 



The ground liiue.stone was applied only in 1915, 1917, and 1919. Attention 

 Is called to the low yield on plat 3, which received no potash. Brief notes are 

 given on the culture and importance of the crop in Florida. 



United States grades for sweet potatoes, H. E. Truax ([/. 8. Dept. Agr., 

 Dept. Circ. 99 {1920), pp. 4)- — The grades here recommended by the depart- 

 ment as a standard for grading and marketing sweet potatoes are based on 

 tentative grade specifications proposed in 1918, as modified after use. 



Summary of three years experiments on the tobacco station at Harrow, 

 Ont., D. D. DiGGEs {Canada Expt. Farms Bui. 4I, 2. ser. {1920), pp. 22).— Th^ 

 work here reported included plant bed experiments; culture, fertilizer, and 

 variety tests ; and studies of methods of harvesting the crop and for the con- 

 trol of insects and diseases attacking tobacco. General directions with regard 

 to various cultural phases also are given. 



In the plant bed experiments glass covered cold beds as compared with canvag 

 covered cold beds always produced plants ready for transplanting about two 

 weeks earlier, and glass covered hot beds led all types of beds by about three 

 days in the production of such plants. Fall steaming of the cold bed proved to 

 be as effective as spring steaming for seedling production by the cold bed 

 method. Plants were pi'oduced eight days earlier on steamed soil than on soil 

 treated with chemicals, and from 8 to IS days earlier than on untreated soil. 

 Steaming for 30 minutes at 100 lbs. pressure appeared adequate for weed and 

 disease eradication. 



Four fall plowed plats of Burley tobacco of f acre each, as compared with 

 similar plats plowed in the spring, gave increases ranging from 67.6 lbs. to 298 

 lbs. of leaf per acre. In the spring the fall plowed plats were disked twice at 

 ■different intervals, and the four remaining plats were plowed and disked once 

 as a preparation for the crop. The results of transplanting tests indicated the 

 following distances as preferable for the tjT)es of tobacco mentioned: Broadleaf 

 Burley 44 by 28 in.,-Standup Burley 42 by 26 in., and Flue-cured 36 by 24 in. 



Fertilizer experiments were conducted with the Flue-cured and the Burley 

 varieties of tobacco. It appeared from the results that on the heavier types of 

 soils a complete fertilizer mixture consisting of 140 Ib^. sulphate of ammonia, 

 500 lbs. acid phosphate, and 200 lbs. sulphate of potash peY acre is likely to give 

 the highest yield and the best quality of Flue-cured tobacco. The best ferti- 

 lizer foi-mula for Burley tobacco, as shown by the outcome of the tests, was 

 400 lbs. sulphate of ammonia, 400 lbs. acid phosphate, and 150 lbs. sulphate of 

 potash per acre. ** 



