MASS. EXPERIMENT STATION BULLETIN 322 



Table 2. — Mean yield* and rank of hay produced in Experiment 1A. 



1928 1929** 1930 1931 1932 Mean 



Lbs. Rank Lbs. Rank Lbs. Rank Lbs. Rank Lbs. Rank Lbs. Rank 



Nitrogen Series: 



High 7346 1 4680 2 5010 1 5120 2 3700 1 5171 1 



Medium 6501 8 4228 8 3668 8 4505 7 3765 8 4533 8 



Low 6181 9 4037 9 3280 9 3514 9 2915 9 3985 9 



Phosphoric Acid 

 Series: 



High 6807 5 4329 6 4102 6 4927 3 3891 5 4811 5 



Medium 6910 4 4356 5 3932 7 4552 6 3703 6 4691 6 



Low 6919 3 4400 4 4188 5 4704 5 3943 4 4831 4 



Potash Series: 



High 679S 6 4709 1 4628 2 5328 1 4347 2 5162 2 



Medium 6947 2 4589 3 4207 3 4732 4 3816 3 4858 3 



Low 6655 7 4238 7 4201 4 4220 8 3540 7 4571 7 



♦Pounds of dry matter per acre, containing about 4 percent moisture. 

 **Only one cutting in 1929. 



Table 3. — Mean yield* and rank of hay produced in Experiment IB. 



1032** 1933 1934 Mean 



Lbs. Rank Lbs. Rank Lbs. Rank Lbs. Rank 



Nitrogen Series: 



High 4576 2 4994 1 4965 1 4845 1 



Medium 4270 5 3733 7 3146 7 3716 7 



None . 2604 9 2952 9 2196 9 2584 9 



Phosphoric Acid Series: 



High 4522 4 4116 4 3464 3 4034 4 



Medium 4222 6 3887 6 3228 5 3779 6 



None 4221 7 3992 5 3188 6 3800 5 



Potash Series: 



High 4705 1 4424 2 3738 2 4289 2 



Medium 4565 3 4300 3 3431 4 4099 3 



None 3841 8 3246 8 2621 8 3233 8 



*Pounds of dry matter per acre, containing about 4 percent moisture. 

 **Second cutting very small on account of dry weather. 



Interpretation of the Results of Experiment 1. — By comparing Tables 2 and 3 

 it will be seen that the results of the two parts of the experiment run almost 

 parallel in the relative effects of the nutrients. Greater differences in yield were 

 obtained from the larger increments of nutrients in part B as was expected. 

 Nitrogen was the most effective nutrient in producing differences in yield, closely 

 followed by potash. Increments of phosphoric acid were of no value in increasing 

 yield of hay in this experiment. 



The best comparisons of these results are in the separate series, for it is only 

 in one series that any two nutrients are held constant with the third variable. 

 One series cannot fairly be compared with another, because of variations in pounds 

 of nutrients applied. Thus, the phosphoric acid series ranks higher as a group 

 than the medium treatment of the nitrogen series carrying the same amount of 

 nitrogen, probably because of the higher amount of potash in the phosphoric 

 acid series. By the same token the ranking of the phosphoric acid series between 

 the medium and low (or none) of the potash series can be explained. 



These results point distinctly to response to nitrogen and potash. The uni- 

 formity and consistency of the results, the length of the experimental period, 

 and the methods employed give confidence in the correctness of this conclusion. 

 In the two experiments there was virtually no response to phosphoric acid. 

 Such small positive or negative effects as were obtained most likely come within 

 experimental error or chance variation. In view of the large amounts of phos- 

 phoric acid applied in certain treatments, particularly in the high treatment of 

 the phosphoric acid series of Part B, it appears that phosphorus was not a limit- 

 ing factor. 



