Mineral Sources of Potassium for Plant Nutrition

D.A.C. Manning Abstract Recently published assessments of nutrient budgets on a national basis have shown that K deficits for developing countries are so substantial that a doubling of world production of potash fertilisers would be required to balance inputs and offtake, simply to meet demands in Africa alone. The price of potassium fertiliser raw materials has increased by a factor of 4 during 2007–2009, approaching $1000 per tonne in some markets. Thus an annual investment of the order of US$5600 million is required to replenish soil K stocks in Africa. In this context it is appropriate to review current knowledge of alternative sources of ...

Evaluation for the Potential Use of Silicate Rocks from Four Volcanoes in Indonesia as Fertilizer and Soil Ameliorant

Silicate rocks, the abundant plant nutrient source in Indonesia, have not been evaluated for use as a fertilizer/and soil ameliorant. This research was aimed to identify (1) mineral and elemental compositions of silicate rocks originated from Galunggung, Kelud, Tambora, and Rinjani Volcanoes and (2) soil properties determining dissolution rate of plant nutrients from the silicate rock fertilizers (SRFs). The rocks were ground with a ball mill for 10 min providing SRFs with medians of particle size of 30 – 50 m. Each SRF was added to 6 soils from West Java, East Java, and Lombok Island at a rate equivalent to 20 t ha-1, incubated for 28 days in a ...