EFFECT OF FERTILIZERS ON MOWINGS 3 



field so situated with reference to a drumloid hill that there is some seepage of 

 water from higher elevations. The soil withstands quite well the effects of mod- 

 erate drouth. The reaction of the soil at the beginning of Part A of the experiment 

 in 1928 was about pH 6.5, and it was maintained near that point throughout. 

 The field had been used for corn, then seeded down in the standing corn with a 

 mixture of timothy and redtop grasses and red and alsike clovers. At the beginning 

 of the experiment the mowing was three or four years old and the vegetation 

 consisted of about 50 percent timothy, 30 percent redtop, 5 percent clovers, 

 5 percent Kentucky blue grass, 5 percent sweet vernal, and 5 percent weeds. 



After Part A had been in progress four years, a parallel experiment (Part B) 

 was started on another part of the same field. The soil conditions were very 

 similar and the mowing of the same age, but the character of the flora was some- 

 what poorer than on Part A when that experiment was begun. 



The quantities of nitrogen, phosphoric acid, and potash and their ratios are 

 given in Table 1. There were three groups of fertilizer treatments, in each of 

 which one nutrient was varied while the other two were held constant. In Part B, 

 the variable nutrient was omitted in one treatment of each series. Nitrogen was 

 supplied by a mixture of equal parts of sodium nitrate and ammonium sulfate; 

 phosphoric acid, by superphosphate; and potash, by muriate of potash. All 

 fertilizers were applied in the early spring about the time that grass begins to 

 grow rapidly, except that in the case of the highest amount of nitrogen, 50 pounds 

 were applied in the spring and the remainder immediately after the first cutting. 



Table 1. — Pounds of nutrients used per acre and their ratios. 



Experiment 1A Experiment IB 



N P,0 5 K 2 Ratio N P*0 S K a Ratio 



Nitrogen Series: 



High 75 37.5 37.5 6:3:3 100 37.5 37.5 8:3:3 



Medium 50 37.5 37.5 4:3:3 50 37.5 37.5 4:3:3 



Low or none 25 37.5 37 . 5 2 : 3 : 3 37 . 5 37 . 5 : 3 : 3 



Phosphoric Acid Series: 



High 50 100.0 50 4:8:4 50 133.4 50 4:10.67:4 



Medium 50 66.7 50 4:5.33:4 50 66.7 50 4: 5.33:4 



Low or none 50 33 . 3 50 4 : 2.67 : 4 50 50 4:0:4 



Potash Series: 



High 50 50 100.0 4:4:8 50 50 133.4 4:4-10.67 



Medium 50 50 66.7 4:4:5.33 50 50 66.7 4:4: 5.33 



Low or none 50 50 33.3 4:4:2.67 50 50 4:4:0 



The plots were 6 by 11 meters, including a border of 1 meter which was cut 

 out and discarded at time of harvest. This made the harvested portion 5 by 10 

 meters (approximately 2 square rods). 2 Plots were systematically replicated 

 5 times. Two crops of hay were taken from the field every year except in 1929 

 when a drouth of unusual severity produced such small second growth as to make 

 cutting inadvisable. The experiment was continued five years, when the quality 

 of the herbage on all but the best plots became so poor that it was decided to 

 plow the field and redirect the experiment. 



In Tables 2 and 3 the results of the experiment for the entire period are sum- 

 marized. 



'As an experiment in the practical application of the metric, system of weights and measures 

 to agronomic field experiments, this field was laid out by this system, field weights were taken in 

 it, and of course the laboratory work was carried out with it. The system was found practicable 

 and in some respects easier to use than the English system. 



