242 



Journal of Agricultural Research 



Vol. VI, No. 6 



The tillering in the early plantings was nearly 100 per cent greater 

 than in the later plantings. The tillering for each variety on fertilized 

 soil for a given date was 50 per cent greater than where no fertilizer was 

 used. The general efifect of the date of seeding seems to indicate a 

 tendency toward a smaller percentage of sterile spikelets in the later 

 seedings. The relation of the number of sterile spikelets to yield does not 

 seem to affect the yield seriously, since the fertilized wheats produced 

 two or three times as much grain per spike as the unfertilized. The 

 difference in yield per spike seems to be due largely to quality (size) of 

 kernel. 



Table IV. — Relation of the effect of different fertilizers and combinations of fertilizers 

 to the occurrence of sterile spikelets 



Treatment. 



Dawsons Golden Chafi 

 (smooth). 



Total 

 num- 

 ber of 

 spike- 

 lets. 1 



Num- 

 ber of 

 sterile 

 spike- 

 lets.' 



Per- 

 cent- 

 age of 

 sterile 

 spike- 

 lets. 



Lehigh (bearded). 



Total 

 num- 

 ber of 

 spike- 

 lets.i 



Num- 

 ber of 

 sterile 

 spike- 

 lets.i 



Per- 

 cent- 

 age of 

 sterile 



spike- 

 lets. 



Nitrogen, phosphorus, and potassium 



Nitrogen and phosphorus 



Phosphorus and potassium 



Nitrogen and potassium 



None 



Nitrogen 



Phosphorus 



Potassium 



16.8 

 18.2 

 18. 2 

 18. 2 

 17.0 



16. 9 



15-9 



17. o 



1.36 

 1.68 

 I. 92 

 I. 08 

 1.05 

 .92 

 1.56 

 I. 32 



8.0 



9.2 



10. 2 



5-9 

 6.1 



S-4 



9-7 



17.9 

 18.2 



17. 2 



17-3 

 16. 7 



18. o 

 15.0 

 16.8 



1.32 

 2.08 

 1.80 

 .92 

 I. 01 

 1.36 

 I. 40 

 I. 24 



7-3 



II. 4 



10. 4 



5-2 



6.0 



7-5 

 9.2 



7-3 



' Average of 25 spikes. 



EFFECT OF FERTILIZERS ON STERIEITY 



The effect of different elements of plant food, singly and in combina- 

 tion, on the number of sterile spikelets is seen in Table IV. The wheat 

 was planted by the centgener method, the individual plants being 6 

 inches apart each way. On each of the plots sufficient fertilizer of 

 each mineral ingredient was supplied to produce a 50-bushel crop of 

 wheat, provided that it were all used. The nitrogen was applied for 

 a 25-bushel crop, it being assumed that the soil carried a fair reserve 

 of this element. The nitrogen was applied in equal parts by weight 

 of nitrate of soda and dried blood; the phosphoric acid was carried as 

 acid phosphate and the potash as muriate of potash. It will be noted 

 that where the fertilizers were applied singly nitrogen gave the lowest 

 percentage — 6.4 — of sterile spikelets as an average for the two varieties. 

 Potash came next with 7.5 per cent, and phosphoric acid stood highest, 

 with 9.4 per cent of sterile spikelets. Where two elements were used 

 in combination, phosphoric acid and potash led, with an average of 



