Section 2
Chapter 1,197

Evaluation of differences in potassium availability in soils of the same exchangeable potassium level

Shaw, J.K.; Stivers, R.K.; Barber, S.A.

Communications in Soil Science and Plant Analysis 14(11): 1035-1050


ISSN/ISBN: 0010-3624
DOI: 10.1080/00103628309367430
Accession: 001196539

K availability was determined by growing corn (Zea mays L.) in pots of soil in a controlled environment chamber. Comparison of K uptake rate per unit root area indicated differing degrees of K availability. The differences in availability among soils were not predicted by differences in cation exchange capacities. The K concentration in solution and the average rate of diffusion more nearly reflected differences in K availability, particularly when the kinetic rate factors of diffusion and mass flow were integrated with root growth and uptake factors in the Cushman mathematical model of K uptake. Utilization of this model demonstrated the importance of using rate factors for ion movement in soil along with plant factors of root growth in predicting K availability.

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