Potassium presents a conundrum for biogeochemists. Potassium is cycled wastefully at the plant level, but it appears to be conserved in the nutrient budgets of entire ecosystems, where it sometimes limits net primary productivity. An increasing demand for K fertilizer may accompany the expansion of agriculture into highly weathered tropical soils, where limited supplies of K may control the distribution and productivity of natural vegetation. However, the molar ratios of 4.6 for N/K in herbaceous plants, 17.3 in current global fertilizer applications, and 0.33 in the commodity price of fertilizer suggest that N is vastly overused and K is vastly over-priced in modern agriculture.

中文翻译：

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陆地生态系统中钾的生物​​地球化学循环的若干思考

钾对生物地球化学家来说是一个难题。钾在植物水平上被浪费地循环，但它似乎在整个生态系统的营养预算中得到保护，有时会限制净初级生产力。随着农业向高度风化的热带土壤扩张，对钾肥的需求不断增加，在那里有限的钾供应可能会控制自然植被的分布和生产力。然而，草本植物中 N/K 的摩尔比为 4.6，当前全球施肥的摩尔比为 17.3，肥料的商品价格为 0.33，这表明现代农业中 N 被严重过度使用，K 被严重高估。