Soil pH and Phosphorus and Potassium Uptake by Maize Evaluated with an Uptake Model
- Jen-Hshuan Chen and
- S. A. Barber
Plant growth and nutrient uptake by plants have been shown to be affected by soil pH. However, the effects have not been evaluated with a mechanistic uptake model that can evaluate the relative influence of soil pH changes on changes in soil supply parameters that influence predicted P uptake. The objectives of this research were to verify the Barber-Cushman nutrient-uptake model under a range of soil pH conditions and to use the model to evaluate the influence of soil pH on the model parameters supplying P and K to maize (Zea mays L.) roots. A pot experiment was conducted to evaluate the accuracy of the model for predicting P and K uptake at soil pH levels of 3.8, 4.7, 5.7, 6.5, 7.6, and 8.3 in Chalmers silt loam (fine-silty, mixed, mesic Typic Haplaquoll). This study showed that the nutrient-uptake model accurately predicted the effect of the soil pH on P uptake (Y = 0.44 + 0.93X, r2 = 0.99) when the change of P from H2PO4 to HPO4 at the higher pH values was accounted for, and predicted K uptake (Y = 67 + 0.94X, r2 = 0.99) without modification for pH.
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