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Early Available Phosphate Cold, wet soils release Phosphorus very slowly, even when soil tests indicate adequate amounts The concentration of the orthophosphate in solution is important for potential diffusion Placement of nutrients with the seed develops zones of higher orthophosphate concentration allowing greater uptake Plants can only absorb phosphate in its Ortho form Orthophosphate is immediately available for crop to use at germination Absorption of nutrient ions is greatest near the actively growing tip of each root. Corn seedlings have a high demand for phosphorus The concentration of phosphorus has to reach 0.5% in five-leaf corn, or the yield potential of that plant is reduced To meet this P requirement, small roots need a concentrated source of P close to the seed Critical Field Corn Growth Stages Growth Stage Days after Emergence Growth Event Importance V3 9-12 Seminal roots, ear shoots Seedling vigor seen, ears established V5 14-21 Ear shoots complete Number of kernel rows established V6 25-30 Nodal root system established. Rapid Growth Phase. Plants ability to take up nutrients is established V-14 50-60 Number of ovules determined Number of kernels per row determined R-1 63-70 Pollen shed begins. Brace roots established. Maximum root mass achieved. Kernel fertilization. Develop ear weight. Kernel fill.
Early Available Phosphate
Growth Stage
|
Days after Emergence | Growth Event | Importance |
V3 | 9-12 | Seminal roots, ear shoots | Seedling vigor seen, ears established |
V5 | 14-21 | Ear shoots complete | Number of kernel rows established |
V6 | 25-30 | Nodal root system established. Rapid Growth Phase. | Plants ability to take up nutrients is established |
V-14 | 50-60 | Number of ovules determined | Number of kernels per row determined |
R-1 | 63-70 | Pollen shed begins. Brace roots established. Maximum root mass achieved. | Kernel fertilization. Develop ear weight. Kernel fill. |