PHOSPHATES IN MASSACHUSETTS AGRICULTURE. 167 



equivalent of available phosphoric acid in a good mixed fertihzer, is usu- 

 ally desirable. 



The yields of corn and potatoes seem to be in general less dependent 

 upon applied phosphoric acid, but in the more soluble forms a fair amount 

 is desirable, especially where early maturity is an object. 



Grasses are affected relatively httle by phosphates; clovers are some- 

 what more responsive, but in top-dressing mowings and pastures the pro- 

 portion of phosphoric acid should be kept relatively low. Three hundred 

 to 500 pounds per acre of acid phosphate in connection with potash and 

 nitrogen materials, or an equivalent in a complete mixed fertihzer rich 

 in nitrogen, will usually suffice in top-dressing mowings. Slag meal will 

 be especially suitable where a large proportion of clovers is desirable, or 

 in top-dressing soils wliich are moist and rich in organic matter. It seems 

 also peculiarly adapted for use in connection with potash as a top-dressing 

 for pastures, bringing in the more desirable grasses and white clover. The 

 usual range in quantity needed appears to be between about 500 and 600 

 pounds per acre. 



In orchard management phosphoric acid seems to favor both fruitful- 

 ness and good quahty, and basic slag meal is in general favor among those 

 who have tried it. This material in orchards, as in mowings and pastures, 

 pecuharly favors clovers and other legumes, and thus indirectly reduces 

 the necessity for nitrogen manuring. It does not, of course, materially 

 affect the need for potash. 



