sources + losses
Phosphorous: Additions (sources):
- Fertilizers (Excess amounts must be applied to over come the phosphorus fixing capacity) - Decaying organic matter - Deposition from eroded rocks by wind and water (dust & precipitation)
Losses: - Plant removal - Uptake by plants via mycorryzal networks - Leaching (But rarely happens because inorganic (plant available) phosphorus gets fixed. By Ca in alkaline soils and by Fe and Al in acidic soils. It gets fixed into an insoluble and immobile form. - Erosion of phosphorous carrying particles
Sulfur:
Additions (sources): - Decaying organic matter - Minerals - Coal burns into the atmosphere then is added to the soil by acid rain or by direct absorption from the atmosphere by plants
Losses: - Leaching of sulfates in solution - Volitilzation of S(2-) to sulfur gasses - Erosion - Plant Removal
Potassium:
Additions (sources): - Fertilizers - Decaying organic matter - Minerals
Losses: - Leaching (translocation down through profile and exit into ground water) - Runoff (to rivers from irrigation or rain) - Erosion
Hope this helps! :-)