i T
E , ..   ` 4 52 _ Bulletin N0. 191. ,
i ·  f · g _,   or more of sixteen per cent acid phosphate, containing sixty-
  i   ,   T four pounds of phosphoric acid? _
  `   . If a farmer is convinced from experience that it pays to l
i ~f _, T use a small amount of complete fertilizer to give the crop a T
      · “ start, and such may be the case, he should at the same time  -
ll  _   understand that it neither supplies any considerable part of  T
  l , the nitrogen and potassium used by the crop, nor does it
l { contribute to the permanent fertility of the soil.  ;
jf § " Surely no one will contend at this late day that a farmer I
lf —i‘‘. _ E A ` should buy nitrogen for ordinary farm crops. For example, T
l   v_ ` a fifty bushel corn crop· requires seventy·iive pounds of  -
    ‘¤ S nitrogen. Four thousand live hundred pounds per acre of ·
{_ qi   , . 2-8-2 fertilizer would have to be used to supply this amount, ‘
  ip  V. granting that the corn could get hold of all of it, which it  i
  • l cannot do. The seventy—iive pounds of nitrogen (required _
  j for fifty bushels of corn) would cost at least $15, and gen-  _
 ,iE erally more, at the usual prices of mixed fertilizers. One _
  , hundred to one hundred and twenty—five pounds of nitrogen J
  would have to be applied in order that the crop could obtain
  , seventy-five pounds from this source.  I
  There are some special crops of high value per acre, such _f 
  l as tobacco, potatoes, cotton, vegetables, etc., on which the _
  » use of the three elements nitrogen, phosphorus and potas- _ _
  sium on some soils gives profitable results. In such cases, I
  would unhesitatingly recommend their use, at least until the i
  soil could be built up to a point where some or all of the
  elements could be left off by rendering the supply in the soil
  available. »
  We recommend the use of acid phosphate more frequently
  . T than rock phosphate. We do so because we have found that .
  acid phosphate is more effective, per dollar invested, than p
  rock phosphate on soils deficient in organic matter, as most
  Kentucky soils are. We are experimenting with both forms. T
  . However, our experiments are on soils quite deficient in i
  . organic matter. If we find that when organic matter is re- J
  stored to the soil the rock phosphate is permanently more
  profitable, then we shall as surely recommend the use of rock j
  phosphate. Results in other States lead us to believe that
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