Laboratory simulation of effects of native clinoptilolite on phosphorus and potassium mobilization in red soil

In order to improve the nutrient efficiency, batch-experiments were conducted to preliminarily study the effects of native clinoptilolite on the unavailable process of water-dissolvable phosphorus and potassium in red soil. Results show that with the clinoptilolite additions, the concentrion of phosphorus and potassium in solution decreases, and the potassium extracted by CaCl₂ increases. The extractable and available phosphorus concentrations in the treatments with clinoptilolite addition decrease in contrast with no clinoptilolite addition at the low level of monopotassium phosphorus; the former is decreased and the latter is increased 9.6%～32.2% at the high level. In red soil, clinoptilolite increases the available phosphorus concentration and decreases the probability of phosphorus pollution in soils with high application of phosphorus fertilizer or high phosphorus concentration. For potassium, native clinoptilolite can be as a sink or a source, which maintains a good potassium concentration.