36 EXPEEIMENT STATION" KECOED. 



"Eight years' continuous selection for bare, as compared with filled tips, 

 shows an average difference of 0.34 bu. per acre in favor of filled tips. Com- 

 paring rough with smooth dented ears, the 7-year average yield favors the 

 smooth type by a gain of 1.76 bu. per acre. 



" Seed ears averaging 88.16 per cent grain have given a 6-year average yield 

 of 64.64 bu. of shelled corn per acre, as compared with a yield of 65.06 bu. 

 from ears averaging 76.38 per cent of grain. A comparison of kernels from 

 the butt, middle, and tip portions of ears shows only 0.57 of a bushel difference 

 in yield, as a 9-year average, and no difference In maturity or any important 

 character. Seed ears having 14, 16, and 18 rows of kernels have been com- 

 pared for 5 years. The 14-rowed ears have led slightly in yield at Wooster 

 and Germautowu, the 16-rowed ears at Carpenter. 



" While the height of plant and ear varies with the season, selecting for high 

 and low ears within a variety has resulted in changing very materially the 

 relative height of ear and also the time of maturity. Low ears are associated 

 with earliness. The comparative yield has not been reduced by selection for 

 low ears. 



" Seed corn grown on rich, as compared with poor soil, and one plant per 

 hill, as compared with five, though larger and apparently of better quality, has 

 not given any larger yield, on the avex'age, than the smaller ears grown under 

 the poorer conditions. The principal causes of barren plants are variations in 

 season, in fertility, and iu time and rate of planting. Such variations in con- 

 ditions of growth have increased the amount of barrenness 200 to 2,000 per 

 cent. Ear-row tests and subsequent crossing of the best ears iu isolated breed- 

 ing plats show possibilities of increasing the yield of corn 5 to 10 bu. per acre, 

 but it seems difficult to go much beyond this amount. Of 13 first-generation 

 crosses grown beside both parents, only two exceeded in yield the better parent 

 variety by more than 2 bu. per acre. 



"A 4-year average gain of 3.9 bu. of shelled corn per acre has resulted from 

 the use of the individual ear germination test. At 50 cts. per bushel for corn, 

 this is a return of $6..50 per hour for testing. Experiments in thinning corn 

 show a 4-year average gain of 8.47 bu. per acre in the case of untested seed 

 and 6.31 bu. for tested seed. The average time required for thinning an acre 

 of corn has been 5.7 hours. 



"As an average of 6 years' tests corn reached its maximum shrinkage August 

 1. Based on shrinkage alone, 62.47 cts, for 70 lbs. of ear corn August 1 is 

 equivalent to 50 cts. November 1. While mid-season and late varieties had 24, 

 29, and 31.04 per cent of moisture, respectively, November 1, on August 1 they 

 carried 10.08 and 10.69 per cent, respectively." 



Fertilizer experiments with corn on Piedmont Cecil sandy loam soil, and 

 varieties, culture, and fertilization of corn on Piedmont Cecil sandy loam, 

 red clay, and valley soils, C. B. Williams, B. W. Kilgore, and A. R. Russell 

 North Carolina 8ta. Bui. 229 (1915), vp. 50).— In this bulletin experimental 

 plats with their treatments are described and the weather conditions are also 

 given for the years 1902 to 1900, inclusive. 



A general summary of the results of fertilizer experiments with corn on the 

 Cecil sandy loam and clay loam for this period is given as follows: 



"The use of a mixture carrying normal amounts of phosphoric acid and 

 nitrogen gave an average increased yield of shelled corn per acre of 69 per 

 cent over the yield secured on the same character of land without fertilization. 

 The net profit, over cost of fertilizer, of this combination was $6.60 per acre. 



" Where a normal amount of potash was used with phosphoric acid in place of 

 the nitrogen there was an average decrease in yield of 8J per cent of shelled 



