EXPERIMENTS WITH PERMANENT PASTURES 25 



some years it is especially abundant in soils having a sufficient supply of nutrients 

 and scarce or entirely absent from those low in nutrients. In off years white 

 clover may be and usually is in small proportion on plots low in nutrients. It 

 follows that if results of treatments are measured in off years they will be quite 

 different from those obtained in clover years. An example of this is afforded by a 

 comparison of the results of experiment B in 1923 and 1930. In 1923, a clover 

 year, there was a marked response to phosphorus and potassium, as shown both 

 by percentage of clover and yields. In 1930, an off year for white clover, there 

 was very little response to phosphorus and potassium, but a marked response to 

 nitrogen. The vegetation was nearly devoid of clover that year. In the same 

 field in 1929 there was considerable white clover. The comparison is brought 

 out by the figures of table 12. 



The dual effect of applied nitrogen and potassium on the protein content 

 of the herbage has been well brought out by the data from experiment C. Potas- 

 sium generally encourages the growth of white clover, and nitrogen appears to 

 discourage it under some conditions and at the same time increases the percent- 

 age of protein in the grasses and weeds. The interaction of these factors has 

 produced some interesting results. In some cases they have worked against 

 each other and in others they have worked in the same direction causing, thereby, 

 a rather high protein content, as was shown in the clippings from plot 22. 



Not only the applied nitrogen, but also the calcium and phosphorus have 

 been reflected in the composition of the plants. It is thought from observations 

 made on experiments B and C that both the nitrogen and calcium-containing 

 fertilizers were important factors in determining the palatability of the herbage. 



Experiment C has brought out the value of seeding white clover on areas 

 practically devoid of it. In many cases white clover appears spontaneously 

 after fertilizers have been applied, while on some areas there is apparently not 

 sufficient seed present, and best results are obtained only after the pasture is 

 seeded. The seeding operation may be beneficial through hastening the process. 



PRACTICAL APPLICATION OF RESULTS 



It is difficult if not impracticable to translate these results into terms of 

 profit and loss. Of course, the safest policy is to let each farmer draw his own 

 conclusions and make his application on the basis of his own judgment, being 

 governed by his conditions. Nevertheless, the following deductions may safely 

 be made. 



First, there is the question of the type of pasture vegetation with which one 

 may expect sufficient improvement to make the investment pay. Results have 

 shown that with vegetation about as poor as may be found on any New England 

 pasture tremendous improvement can be effected, but at a questionable cost. 

 Everything else being equal, it seems that the money for improvement should 

 be invested first in those pastures which have a fairly good vegetation to begin 

 with. 



The question of physical conditions, texture and structure of the soil, and 

 topography, which have nmch to do with the ability of a soil to withstand drought, 

 should be considered. These concUtions are probably of considerable importance 

 in determining \\hite clover cycles, and we have seen that clover years play an 

 important role in the success of mineral treatments. 



In the choice of a pasture for improvement the location of the area must be 

 considered. A pasture occupying a more or less advantageous position on account 



