Natural rock powder as an alternative potassium fertilizer: evidences from a short-term Chinese cabbage cultivation experiment

초록

Purpose: Natural rock powder fertilizer (NRP), primarily composed of potassium (K) feldspar (KAlSi3O8), has attracted attention as a mineral-based K source for organic agriculture. This study aimed to evaluate the feasibility of NRP as an alternative to conventional mineral K fertilizer for Chinese cabbage (Brassica rapa L.) cultivation. Methods: A field experiment was conducted to compare a conventional mineral fertilizer treatment with four different NRP:treatments: two application rates (standard and double rates) and two application modes (micro-particles and foliar application). The chemical properties and nutrient availability of NRP were analyzed, and Chinese cabbage growth, plant nutrient concentrations, and soil chemical properties were evaluated. Results: Fresh weight, head width, head length, and plant K concentrations did not differ among treatments. In particular, the NRP standard-rate treatment showed plant growth and tissue K concentration comparable to the conventional mineral fertilizer treatment, suggesting the potential of NRP as a K source for Chinese cabbage cultivation under the tested soil conditions. In addition, plant calcium (Ca) concentrations were significantly higher in NRP-treated plants, suggesting that NRP may also supplement Ca due to its high soluble Ca contents. Conclusions: These findings demonstrate the potential of NRP as an alternative K source for Chinese cabbage cultivation particularly in organic farming systems. However, further studies are needed to evaluate its long-term effects on K and other mineral nutrition under field conditions.

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