1382 The Vegetable Industry in New York State 



must be purchased for later growth, to use nitrate of soda, 

 making' a second application just before it is needed. If a large 

 amount is applied at one time, early in the season, much may be 

 lost through leaching before the plants can use it. The danger of 

 such loss will be reduced in soil full of humus. 



When manure is made on the farm and is applied to a sod 

 in the late fall or early winter, so that it is broken up by the 

 frost and rains, there is little damage from rot or disease which 

 may occur with manure applied just before planting. This will 

 usually supply all the nitrogen needed, and all that need be pur- 

 chased is phosphoric acid and potash. I have had excellent re- 

 sults from 1,800 pounds of South Carolina rock and 200 pounds 

 of muriate of potash. This will analyze about 12 per cent, of 

 phosphoric acid and 5 per cent, of potash. We hear much of the 

 need of a large amount of the last named for potatoes, and many 

 potato fertilizers contain as high as 12 per cent. For muck soils 

 and those deticient in minerals this is doubtless none too much, 

 but for most Xew York soils which are high in potash, all the evi- 

 dence goes to show that from 4 per cent, to 5 per cent, is ample. 

 In a few cases larger amounts have given better yields, but when 

 the cost of the extra amount was figured out the increase did not 

 pay for the extra outlay. All recent experiments show that 

 phosphoric acid is a controlling factor. Of this there should be a 

 surplus which will not be lost, but is available for subsequent 

 crops. In a dry time the soluble phosphoric acid tends to revert 

 or lock up. When rain is lacking until late in the season (which 

 will make the plant food again available), if there is a minimum 

 of this food, not enough will become available in the short time in 

 which it is needed. 



A very good potato fertilizer for ordinary soil, when one ap- 

 plies all three at planting time, can be made from 400 pounds of 

 nitrate of soda, 200 pounds high-grade tankage, 1,200 pounds of 

 South Carolina rock and 200 pounds of muriate of potash. This 

 will analyze 3.7 per cent, nitrogen, 9.4 per cent, phosphoric acid 

 and 5 per cent, of potash, and, if the chemicals are purchased, 

 should cost not over $28, including mixing. In the season of 

 1915, with the scarcity of potash, and consequent almost prohibi- 

 tive price, ordinary directions relative to potash are non-effective. 



