May, 1938] Experiments With Grass Hay 23 



Under growing conditions at Durham, the haj' in this test was cut at 

 approximately the following stages of maturity : 



June 10 : Heads appearing 



June 20 : Headed 



June 30 : Bloom appearing 



July 10 : Past bloom 



July 20 : Seed dough 



July 30 : Seed nearly ripe 



SUMMARY 



Experimental data indicating how grass ha}' yields and feeding value 

 may be improved are discussed in this bulletin. 



In a test at Greenland covering three years' work, 32 pounds of nitro- 

 gen from 200 pounds of nitrate of soda increased the hay yield 1,462 

 pounds per acre. Thirty-two pounds each of phosphoric acid and pot- 

 ash coming from superphosphate and muriate of potash increased the 

 yield 728 pounds per acre, wdiile a complete fertilizer equal to the two 

 treatnients caused an increase of 2,159 pounds of cured hay per acre. 

 These increases were produced at a cost of $5.48, $7.88 and $6.36 per ton 

 respectively. 



Rapid soil tests of the plots on this field indicated moderate amounts 

 of available phosphoric acid and potash, due no doubt to uniform ap- 

 plications of complete fertilizers in each of three years preceding the 

 seeding of the land. 



On a heavy soil which had been in hay for a long time and which had 

 not been generously treated with phosphoric acid and potash, complete 

 fertilizers gave better returns comparativeh' than nitrogen alone. Where- 

 as in the Greenland soil a complete fertilizer increased the yield over 

 nitrogen alone approximately 50 per cent, on this heavy soil complete 

 fertilizers gave approximately 200 to 300 per cent greater increase in 

 production than the nitrogen carriers used. (Tables II and III.) 



An 8-6-6 fertilizer mixed from highly soluble materials proved slight- 

 ly more effective in increasing yields than a commercial 8-6-6 mixture. 



Nitrogen recovery was greatlj" increased on this soil by the use of 

 phosphoric acid and potash in mixed fertilizers. (Table IV.) 



Nitrogen alone applied about the time growth starts increased slightly 

 the percentage of protein in the forage, but the use of complete fertilizers 

 had little effect or slightly decreased the protein percentage in the hay 

 (Table V), although both nitrogen and complete fertilizers markedly in- 

 creased the total amount of protein per acre. 



None of the fertilizers stimulated the second crop yields to a significant 

 extent. One application of fertilizer only was made, and this was ap- 

 plied at ubout the time growth starts in the spring (Table VI) . 



In another test (Table VII), nitrogen and phosphoric acid stimu- 

 lated grass hay production more than nitrogen and potash. Rapid soil 

 tests indicated, however, that there was probably enough potash for 

 maximum grass hay crops whereas the level of available phosphorus was 

 very low except on the plots where phosphoric acid was used. 



Nitrate of soda applied in mid-September was practically as effective 

 in stimulating yields the following season as when the same amount of 



