Bulletin No. 31. November, 1591. Agricultural Experiment Station -OF THE- AGRICULTURAL AND MECHANICAL COLLEGE, AUBURN, ALABAMA. IRISH AND SWEET POTATOES. J. S. NEWMMAN AND JAS. CLAYTON. State on application to the Agricultural Experiment Station, Auburn, Ala. All communications should be addressed to Experiwtent Station, Auburn, Alabama. THE BROWN PRINTING CO., PRINTERS, -MONTGOMERY, ALA. XW'The Bulletins of this Station will be sent free to any citizen of the METHODS OF APPLYING MANURE TO IRISH POTATOES AND COMPARISON OF VARIETIES. An inquiry from Mobile county, received last January, suggested the following experiments with different modes of applying the manure to Irish potatoes as well as that with methods of cultivation. The fact that all three of the methods of applying the coarse manures, commonly used with potatoes, are employed in common practice, suggested that it mattered but little which was adopted. The results show that while there is a difference in the average yield, of the nine varieties, of a little more than eighteen bushels per acre, there is in some instances a greater difference than this in the yield of the same variety on different plots. The inference is, therefore, that the variation, which occurs on the plots differently manured, is not greater than that which might reasonably be expected from the same variety upon different plots under normal conditions. There are nine experiments in each plot. A comparison of the nine varieties used in connection with each inquiry as to the method of applying the manure. It is interesting to note the difference in the proportion of culls in the different varieties. The Charles Downing is conspicuous in this respect for its large number of small potatoes49.73 bushels out of a total average yield of 227.34 bushelswhile the Early Sunrise, though giving the largest yield, has only a small per cent. of culls-20.08 bushels out of an average total yield of 316.04 bushels. The difference in the extent to which the same varieties were affected with scab upon the different plots, is not enough to justify even a suspicion that this is due to the relative position of the seed, and hence of the potatoes, to the measure, except in the case of the Maine and Early Sunrise varieties in plot 1. While the results in the tabulated statement are not decisive, they are interesting. EXPERIMENT WITH VARIETIES OF POTATOES AND METHODS OF APPLYING MANURE. YIELD PER ACRE IN How PLANTED AND BUSHELS. N NAMES OF VARIETIES. FERTILIZED. FORM. SCAB. chant- Culls Mr fotal g- 6able. PLOT No. 1. ........... I Beauty of ebron....... 2 Burbank Seedling.................. ............ 3 Charles Downing...... Southern Grown Early Rose........... 5 [oughton Rose or Maine.------------6 Early Sunrise ...................... 7 Empire State....................... 8 Peerless........................... 9 White Star. .......................... 4 MVanure scattered in furrow and potatoes dropped on it. Oblong .. Long .. Roundish... . Mlight. Oblong... Badly. ... . Long... Free..: Oblong Roundish fiat. Slight... Long.... 51.45 249.9C 22 7h 105.75 45.57 229-32 231.52 7236 46 01 234 19.84 285.91 33.95 163.16 52 92 321.19 296.20 25.72 321.92 [93845 282 91 183.75 205 8( 198.45 266.07 124 21 268.27 224 91 PLOT No. 2. .... Potatoes dropped iIn 10............. Slight .. 10 Beauty of Hebron ..................... furrow and manure 11l. ....... Very slight. . 11Burbank'Seedling ..................... Free.. scattered on them.1 ............. 12 Charles Downing...................... .Slight. 13..... 13 southern Grown Early Rose......... . 14...... 14 Houghton Rose or Maine............... 224 91 29 40 254.31 1 :307 2' 23 52 330.75 154.31 47.77 202.08 216 82 33 07 249 89 [94.77 14.70 209 330.01 22 05 352.06 2 3 5 Sunrise....................... ............ ............... 17 Peerless....... ..... 15 Early 47 4 . 16 Empire State ............ 15.......Free.... 16.......... Slight.... c 17.......... 18 ........... 6 18 White Star............................ 4 ... 166 84 25 72 192 56 7 309 43 24.25 333 68 & 288.86 22 78311 64 9 243 68 EXPERIMENT WIIH VARIETIES OF POTATOES AND METHODS OF APPLYING MANURE-CONTINUED. YIELD PER ACRE IN How PLANTED AND NAMES OF VARIETIES. FERTILIZED. FORM. SCAB. Mer- BUSHELS. S y d 6 PLOT Chant- Culls Total able. No. 3. .. .... . 19 Beauty of Hebron....,................... Manure scattered in 19 ... 20 Burbank 21 Charles 22 Southern Grown Early Rose .. Seedling. .... ................. Downing.... .......... .. Slight... . furrow, scooter run 20 ,...... 11 it to mix thor- 21 oughly and potato 22 ,..... 23 Hloughton Rose or Maine................. 24 Early Sunrise........... ............. 26 dropped on it. 23 ...... 24............ . ............ ..... ... 252 1( 34 54 286 64 1 ),. 88 13 23 313 11 2 Free . Slight.. 9 194.77 55.S6 250 63 49 90 14.70 261 60 38 96 213 89 .. .. . 4 . ".... .. 170 52 31 60202 12 5 . 291 79 18 3.310 16 6 .. 174.93 297.61 7 25 Empire State..................................... Peerless..................................26...... 27 7 White Star................ 25............... ..... 20 58:318 25 S .. 60 92 Iil 02271 94 9243 61 The accompanying tabulated statement showing results of different methods of cultivating the Irish potato needs little comment. The soil upon which the potatoes were grown is sandy and dry, and yet mulching between the rows proved apparently injurious. The half or flat bed culture produced one hutidred bushels per acre more than the mulched. This experiment'is so much involved in the character of the season during the growth of the potato that it cannot be taken as a reliable guide. The season of growth was sufficiently moist without the mulch. EFFECTS OF DIFFERENT METHODS OF CULTIVATING IRISH POTATOES. NAME OF VARIETY. How Cultivated. Peerless.......... Peerless... ..... Peerless .. Level culture....... Slight ... 207.27 19.84227.11 Half bed........... Badly.... 277.09 22.05299.14 . Full bed .......... .Mulch between rows Slight .... 253 57 18 37 271 94 " . 185 22 14 70 199 92 Peerless .. The question as to whether the Irish potato should be cut for seed or the whole tuber planted, has been a mooted one amongst growers. The results point to the propriety of planting the whole potato as decisively as a single experiment could well do. The increased yield resulting from the use of the whole potato-of that cut to one eye-154.34 bushels per acre will justify the additional expense for seed. , RESULTS FROM DIFFERENT MODES OF PREPARING THE SEED. NAME OF VARIETIES How Treated. - - Peerless......... Peerless......... Cut to one eye .... Cut to two eyes. . Badly. .. 181 54 16 92 198.46 264.60 25.72 290 32 205 80 23 52 229 32 316 05 36 75 352.80 FOR Slight... Slight ... Badly.... Peerless.......... Cut to three eyes. Peerless . .... Whole potato A COMPARISON OF LARGE WITH SMALL SWEET POTATOES BEDDING. While the majority of sweet potato growers use the small potatoes for bedding, because of the cheapness and the greater number of eyes or buds in a given quantity, some of the most successful growers have used large potatoes for seed with uniformly satisfactory results. The large potatoes produce very few sets, and, hence, to secure plants for a large area a large quantity of roots of edible size is required. On the other hand, the small potatoes having more surface exposed in a given area of bed, produce plants in greater abundance. Economy, therefore, seems to point to the use of the culls. This practice is not pursued in other vegetables or field crops; but, as a rule, the best is used for seed. Some successful growers use for seed only roots grown from vines. The results in this case are decidedly in favor of the use of large potatoes for bedding. This would be the natural course to be pursued if improvement of the potato was the object in view. As in the case of the use of whole potatoes already discussed, the increased yield justifies the additional expense in the value of seed used. RESULTS OF COMPARISON OF LARGE AND SMALL SEED SWEET POTATOES. PLANTS DRAWN FROM BEDDING LARGE POTATOES. PLANTS DRAWN FROM BEDDING SMALL POTATOES. DCIJ m ri~ )CI I) rcc) a, 0 36 47 136.19 99.72 75.20 23 56 98.76