534 



EXPERIMENT STATION RECORD. 



[Vol. 38 



tinuation of work previously noted (E. S. K., 21, p. 428), this reports the results 

 of fertilizer tests with cotton j^rown continuously on a Cecil sandy loam soil In 

 the upper Piedmont section of South Carolina, including tests of individual fer- 

 tilizer ingredients, mixed fertilizers, lime, and manure. Crop yields for each 

 treatment for each year of the nine years 1906-1915 are tabulated and discussed. 

 Additional tests of various fertilizer formulas for the period of 1912-1915, 

 inclusive, are noted. 



It is concluded that heavy fertilization is required to maintain high yields of 

 cotton on this soil and that the average of one-third of a bale per acre had not 

 been maintained on the unfertilized plats during the last years of the experi- 

 ment. Acid phosphate and manure maintained high yields throughout the test^ 

 phosphorus apparently being the principal limiting factor with nitrogen a close 

 second. Potash increased yields sufficiently to pay the cost of the fertilizer 

 at pre-war prices but can not now be used profitably. ISIanure supplemented 

 with phosphorus resulted in an increased yield of seed cotton of 88 lbs. per ton 

 of manure used. 



In comparing the value of applications of two sources of plant food it was 

 noted that with phosphoric acid and nitrogen the yield was 25 lbs. less than 

 with a complete fertilizer, with phosphoric acid and potash 342 lbs. less, and 

 with nitrogen and potash 539 lbs. less. Lime could not be applied profitably. 



A fertilizer containing approximately 10 per cent available phosphoric acid, 

 nitrogen equivalent to 3 per cent of ammonia, and no potash is deemed best for 

 cotton on this soil under present conditions. 



Whole V. cut potato tubers for planting' on irri*^ated land, I, II, L. C. Aichek 

 and J. S. Welch {Jour. Amer. Soc. Afiron., 9 (1917), No. 5, pp. 217-230, pis. 

 2). — Experiments are reported regarding the size of tuber pieces to plant for 

 the most economical production of Irish potatoes under irrigation. The work 

 was conducted in Idaho at the Aberdeen substation from 1913 to 1916, inclusive, 

 where 8-, 4-, and 3-oz. tubers were planted whole, halved, and quartered, and 

 at the Gooding substation from 1914 to 1916, inclusive, using 8- to 10-oz. and 

 4- to 6-oz. tubers planted whole, halved, and quartered, and 2- to 3-oz. tubers 

 planted whole and halved. Idaho Rural was used at both stations. 



The average results obtained at the Aberdeen substation are tabidated below 

 and show that although the total yield from whole tubers was 14.4 per cent 

 more than from cut tubers, the percentage of marketable tubers from cut seed 

 pieces was IS per cent more than from whole seed pieces. 



Results of tests tcith ivhole and cut potato tubers at Ahcrilccn, Idnho, 1913-1916. 



Bond of tuber set planted. 



8-oz. wliole 



8-oz. halved 



8-oz. quartered 



4-oz. whole 



4-oz. halved 



4-oz. quartered 



3-oz. whole 



3-oz. halved 



3-oz. quartered 



Whole average 



Halved , average 



Quartered, average 



Stand. 



Per ct. 

 00.91 

 09.97 

 ,V9 2S 

 09. 99 

 09. 99 

 89. 31 



100.00 

 OR. S7 

 S2. 19 

 09. 07 

 99.61 

 SC.92 



Stalks 

 per 

 hill. 



S.67 

 4.71 

 2. 03 

 5.41 

 2.98 

 1.71 

 4.82 

 2.64 

 1.72 

 6.30 

 3.44 

 2.02 



Yield per aero. 



Total. 



Bush. 

 392.9 

 333.5 

 314.0 

 368.7 

 332.9 

 322.7 

 361.7 

 355. 5 

 262.7 

 374.4 

 340.6 

 299.8 



Market- 

 able. 



Bush. 

 200.6 

 210.5 

 218. 2 

 171.0 

 220.1 

 250. 9 

 201.1 

 253. 8 

 201.5 

 191.0 

 228. 1 

 223.5 



I'er- 

 cent- 

 ase of 

 market- 

 able 

 tubers. 



.52.6 

 G5. 2 

 69.1 

 46.3 

 66.1 

 77.4 

 54.2 

 68.8 

 78.0 

 51.0 

 66.7 

 71.5 



Number of 



tubers per 



bushel. 



Market- 

 able. 



209 

 190 

 152 

 179 

 171 

 152 

 196 

 162 

 170 

 194 

 176 

 15S 



Culls. 



501 

 4X9 

 410 

 ■^(•.3 

 418 

 414 

 449 

 417 

 412 

 472 

 421 

 412 



Weiflit per 

 tuber. 



Market- 

 able. 



Oz. 



4.6 

 4.9 

 5.7 

 5.3 

 5.7 

 6.2 

 4.9 

 5.9 

 5.6 

 4.9 

 5.5 

 5.8 



Culls. 



Oz. 



1.8 

 2.1 

 2.3 

 2.0 

 2.2 

 2.3 

 2.1 

 2.3 

 2.2 

 1.9 

 2.2 

 2.2 



