PHOSPHATE AND POTASH

New Zealand Herald, Volume LXXV, Issue 22948, 28 January 1938, Page 16

PHOSPHATE AND POTASH

ADDITION OF LIME [from a special cohresponuent] Farmers in the Rangiriri district recently asked the Minister of Agriculture, the Hon AV. Lee Martin, to ascertain for them what chemical 01 other effect would ensue from the addition of lime to a superphosphate-pot-ash mixture. The Minister has submitted the following report which he had obtained from his department in reply to the question: " The addition of lime to a supcr-pot-nsh mixture would have no chemical effect whatever on the potash, but it thoroughly mixed would revert part or whole of the water-soluble phosphate of the super to water-insoluble phosphate, according to the amount of lime added. The Avater-insoluble phosphate is quite readily available in the soil solution. The same process is completely carried out in the commercial manufacture of reverted super. It is probable that the lime would improve the running qualities of the mixture, especially if kainit or muriate of potash were the form of potash used. It is also desirable that the mixture be used immediately after mixing as otherwise a certain amount of caking might occur. Under these circumstances reversion is not likely to he extensive."