8 MASS. EXPERIMENT STATION BULLETIN 322 



Table 6. — Effect of different forms of nitrogen, used as top-dressing, 

 on the dry matter and protein content of hay. 



Date Sampled Treatment Dry Matter Protein in Dry Matter 



(Percent) (Percent) 



[Sodium Nitrate 24.5 20.1 



Ammonium Sulfate 25.2 17.1 



May 21, 1934* \ Calcium Cyanamide 24.8 19.6 



Urea 25.9 16.7 



I Check 28.8 13.5 



I Sodium Nitrate 27.1 14.7 



Ammonium Sulfate 29.3 12.4 



Calcium Cyanamide 2S.2 14.2 



Urea 28.3 13.1 



Check 28.3 11.4 



1 Sodium Nitrate 46.8 10.3 



Ammonium Sulfate 46.9 9.4 



Calcium Cvanamide 54.4 10.5 



Urea 52.3 9.1 



Check 48.8 9.4 



^Plucked samples. 

 **Samples tanen from swath soon after mowing, but probably a little moisture 

 had been lost before sampling. 



Summary 



Two experiments were conducted in prolonging the life of old mowings by 

 top-dressing with chemical fertilizers. In the first one mixed fertilizers containing 

 different proportions of nitrogen (N), phosphoric acid (P 2 5 ), and potash (K 2 0) 

 were used. The soil was a Merrimac fine sandy loam, somewhat superior for grass 

 to the average soil of^this type. The quality and yield of the mowing were im- 

 proved by fertilizer mixtures high in nitrogen and potash. Little or no benefit 

 was derived from applied superphosphate. A fertilizer having a ratio of N, P 2 5 , 

 and K 2 of about 3:1:2 is recommended for old mowings on soils of this type. 

 On soils of this and closely related types the quality of mixed grass mowings will 

 deteriorate to such an extent in 6 to 8 years, in spite of rational fertilization, that 

 reseeding is desirable. 



In another experiment conducted on a similar soil different forms of nitrogen 

 fertilizers were applied as top-dressing. Sodium nitrate, ammonium sulfate, 

 calcium cyanamide, and urea were used in quantities to supply nitrogen at the 

 rate of 50 pounds per acre. The increase due to the fertilizer was a little over 

 100 percent. The data were inadequate to warrant a conclusion as to the relative 

 merits of the several materials used. 



Analysis of samples of grass taken at different stages of maturity showed that 

 the total nitrogen content decreased as maturity advanced. In the earliest stage 

 of growth the nitrogen fertilizers increased the content of nitrogen about one 

 fourth to one half; in the last stage there was little or no difference in the per- 

 centage of nitrogen in the fertilized and unfertilized grass. 



Publication of this Document Approved by Commission on Administration and Finance 

 4M-9'35. No. 5534 



