6 MASS. EXPERIMENT STATION BILLETIN 2S1 



natural met hod of iiUTea.sing the supply of ninierals to tlH> grazing animal is by 

 enrichment of the i)astures.'' An extensive Ijibliography is appended to Orr's 

 book. 



EUenberger and others (5) show that there is considerable variation in the 

 yield of unfertilized \'erniont pastures. Total acre yields of dry clippings from 

 14 pastures varied from 261 to 4,031 pounds, and averaged 1748 pounds. Like- 

 wise, there was considerable variation in the percentage of crude protein and 

 minerals from the different pastures. In general, the percentage of protein, cal- 

 cium and phosphorus was higher in the grass from the better pastures. 



Abbott (1) has reported the results of 103 tests of fertilizer chemicals applied 

 as top-dressing to pastures in 15 northern states and Ontario. There was a wide 

 variation in the response to lime, phosphorus, potassium, and nitrogen, but the 

 results in general show benefits from both minerals and nitrogen. 



Mortimer and Richards (8) have reported results from top-dressing permanent 

 pastures situated on Miami silt loam at Madison, Wisconsin. Lime alone gave 

 an increase of 15.6 per cent; lime and superphosphate, 42.6 per cent; and lime, 

 superphosphate, and potash, 153.2 per cent. The effect of potash in encouraging 

 the growth of white and alsike clovers was marked. Nitrogen alone or in connec- 

 tion with the minerals was only slightly effective. 



Odland and others (9) have published results of pasture experiments conducted 

 on Dekalb clay loam in West Virginia. Lime, superphosphate, and manure pro- 

 duced best results, followed in order by lime and manure, lime and superphos- 

 phate, superphosphate, nitrate of soda, and lime. Potash fertilizers were not 

 used as such. Seeding experiments showed "conclusively that scattering seed 



over a pasture of this type without other treatment is useless Like seeding, 



disking a pasture without other treatment cannot be expected to produce an.y 

 benefits. ■■ 



Recently, Prince and others (11) have published data from experiments in 

 top-dressing old pastures in New Hampshire. Data from ten outlying experiments 

 for one year are reported. Results in terms of pounds of protein per acre show a 

 response to phosphorus, lime, and potash in 4 cases each, and response to nitro- 

 gen in 7 cases. It is pointed out that the greatest response to minerals was ob- 

 tained on pastures originally having a fair or good stand of white clover, and the 

 greatest response to nitrogen from those pastures which contained practically 

 nothing but grass. Likewise, results from experiments made on 6 pastures in 

 Vermont by Van Alstine and Cook (13) show response to lime in 3 cases, to 

 phosphorus in 4 cases, to potash in 3 cases, and to nitrogen in 5 cases. 



Summarizing the literature bearing particularly on the question of top-dress- 

 ing permanent pastures, it may be stated: 



1. Generally, lime has been shown to Ije the fiist limiting factor in the 

 productivity of run-out joermanent pastures of the Northeastern States. 



2. Phosphorus has been found to be deficient in most of the pasture soils of 

 this region. 



3. Marked response to potassium has been reported from soiiie experiments, 

 but jxitassium has not hccn as generally deficient as phosphorus. 



4. In most of the experiments reported there has been some response to 

 applied nitrogen. This response; has been greatest in case of pastures whose 

 herbage ccjnsisted mainly of grasses, and least in those containing a large propor- 

 tion of white clover. There is considerable question as to the economy of aj)i)l.\- 

 ing fertilizer nitrogen to pastures of this latter type. 



