THE EFFECT OF NITROGEN ADDITIONS ON FERTILIZER‐PHOSPHORUS AVAILABILITY. II 1
1958; Wiley; Volume: 9; Issue: 1 Linguagem: Inglês
10.1111/j.1365-2389.1958.tb01908.x
ISSN2056-5240
Autores Tópico(s)Phosphorus and nutrient management
ResumoSummary A field and greenhouse study has been made of the effect of nitrogen on the utilization of fertilizer phosphorus by cereal grains. A marked increase in utilization when nitrogen was mixed with either NH 4 H 2 PO 4 or Ca(H 2 PO 4 ) 2 was shown to occur only when the nitrogen was in the ammonium form. Nitrate sources of nitrogen were relatively ineffective. Placement of nitrogen was important as increased uptake only occurred when the ammonium ion was intimately associated with the phosphorus fertilizer. This stimulative effect of the ammonium ion on phosphorus uptake occurred at a very early stage of crop growth. Rapid ammonium‐ion absorption by young cereal seedlings occurred irrespective of whether the ammonium source of nitrogen was mixed with, or separated from, the phosphorus carrier. Thus the ammonium ion appears to be the dominant factor; it indirectly influences the plant's ability to take up phosphorus, rather than altering in any way the availability of the applied phosphorus fertilizer.
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