1382 Tur Vecreraste Inpustry 1x 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 phosphorie 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 deficient in minerals this is doubtless none too much, 
but for most New 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, 
snould 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. 
