150 



MASS. EXPERIMENT STATION BULLETIN 230 



The greatly increased yield of protein on the best treated plot is most sig- 

 nificant, with a total production equal to that contained in 2400 pounds of 

 Vi'iieat bran. The cause of tiiis change is of course the stimulation of clover 

 and the suppression of the weeds brougiit about by the use of lime and 

 fertilizer. 



TiiK (iRASs Cycle 



White clover, however, comes and goes. By the fall of 1924 it had disap- 

 peared from these plots almost absolutely and been replaced by i)lue grass. 

 In the spring of 1925 no clover was in evidence, even on tiiose plots whic^h 

 had been densely carpeted in the summer of 1923. In the early summer of 

 192.5, however, drouth conditions prevailed, to be broken during the end of 

 June by generous rains. These conditions favored clover, and by the end of 

 tliat year it was once more dominant on all of the l)etter fertilized areas. 



It is impracticable to translate the above figures into terms of profit and 

 loss. We have no means of knowing how long a time fertilizer will continue 

 to show benefit. Yet the fact that large areas have already reverted to forest 

 shows what nmst happen to existing pastures in case fertilizer be not applied; 

 or in case the price of milk be too low to make profitable such fertilizer 

 application. 



What Feutilizicks Are Needed. 



On the relatively coarse grained, depleted granitic soils of the Station farm, 

 potash was the plant food most needed. Best growth was obtained with lime. 

 Acid phosphate applied in addition to lime and potash still further bettered 

 the yield. The total expense of application of these three materials was, of 

 course, very heavy. On heavier pasture soils, acid phosphate may be all that is 

 required. In certain demonstrations west of the Connecticut River, instituted 

 by the Department of Agronomy, M. A. C, this is indicated most clearly. It 

 is probable that, where the soil is fairly close grained and has a favorable 

 moisture supply, acid phosphate, with lime if the soil be extremely acid, will be 

 all that is required. These of course must be applied as top dressing, which 

 means that action is certain to be relatively slow. 



The fertilizing of pastures is a most interesting field for farm experiments. 

 There are, however, certain discouraging conditions attending it. Returns 

 from fertilizer application are always delayed, for only by stimulating white 

 clover and grass so that it can crowd out the weeds is the better pasture 

 secured. If the weather be dry, there may be a period of weeks or even of 

 montiis in which there will be no growth on either fertilized or unfertilized 

 portions of the pasture. Even when good growth is produced, as should 

 usually be the case, the fact may not be noticed, for increased forage may be 

 pastured off as rapidly as it is grown. Yet with all of these uncertainties, the 

 goal is worth the effort. A pasture which is in a weedy or run-down condi- 

 tion because of a lack of plant food can be brought back to productive con- 

 dition only by the use of plant food. 



