Potash—A vital agricultural nutrient sourced from geologic deposits

Abstract

This report summarizes the primary sources of potash in the United States. Potash is an essential nutrient that, along with phosphorus and nitrogen, is used as fertilizer for growing crops. Plants require sufficient potash to activate enzymes, which in turn catalyze chemical reactions important for water uptake and photosynthesis. When potassium is available in quantities necessary for healthy plant growth, disease resistance and physical quality are improved and crop yield and shelf life are increased. Potash is a water-soluble compound of potassium formed by geologic and hydrologic processes. The principal potash sources discussed are the large, stratiform deposits that formed during retreat and evaporation of intracontinental seas. The Paradox, Delaware, Holbrook, Michigan, and Williston sedimentary basins in the United States are examples where extensive potash beds were deposited. Ancient marine-type potash deposits that are close to the surface can be mined using conventional underground mining methods. In situ solution mining can be used where beds are too deep, making underground mining cost-prohibitive, or where underground mines are converted to in situ solution mines. Quaternary brine is another source of potash that is recovered by solar evaporation in manmade ponds. Groundwater from Pleistocene Lake Bonneville (Wendover, Utah) and the present-day Great Salt Lake in Utah are sources of potashbearing brine. Brine from these sources pumped to solar ponds is evaporated and potash concentrated for harvesting, processing, and refinement. Although there is sufficient potash to meet near-term demand, the large marine-type deposits are either geographically restricted to a few areas or are too deep to easily mine. Other regions lack sources of potash brine from groundwater or surface water. Thus, some areas of the world rely heavily on potash imports. Political, economic, and global population pressures may limit the ability of some countries from securing potash resources in the future. In this context, a historical perspective on U.S. potash production in a global framework is discussed.

A Review of Libyan Soil Databases for Use within an Ecosystem Services Framework

“…Table 10. The yearly replacement costs of K (based on a moving 5-year average price of U.S. $500 per metric ton of potassium chloride, KCl [27]) using the kg/y values reported in Table 11 the each of the Libyan territories and the capital and major cities.…”

Quantifying and Mapping Atmospheric Potassium Deposition for Soil Ecosystem Services Assessment in the United States

“…Potassium is an important nutrient, and Sheldrick et al (2002) reported that the depletion of K is particularly severe which results in an annual global deficit of 20 kg K ha −1 . In terms of monetary cost, this annual global deficit is valued at just over $19 ha −1 based on a moving 5-year average price of U.S. $500 per metric ton of potassium chloride (KCl) (Yager, 2016). According to Sheldrick et al (2002), soil and surface balances for potassium can vary by different regions in the world.…”

“…In terms of monetary value, this potassium requirement would cost $34.5M each day based on FIGURE 1 | The role of atmospheric potassium deposition in the gains and losses of available soil potassium under average field conditions (adapted from Brady and Weil, 2002). a moving 5-year average price of U.S. $500 per metric ton of potassium chloride (KCl) (Yager, 2016). Given a U.S. population of 325.7 million people (2017), and a recommended daily intake of 4.7 g per person per day of K, it would require at least 1,531 metric tons/day of potassium to ensure that every person is able to meet their daily potassium requirement.…”

“…Given a U.S. population of 325.7 million people (2017), and a recommended daily intake of 4.7 g per person per day of K, it would require at least 1,531 metric tons/day of potassium to ensure that every person is able to meet their daily potassium requirement. In terms of monetary value, it will cost nearly $1.5M per day based on a moving 5-year average U.S. price of $500 per metric ton of KCl fertilizer (Yager, 2016).…”

“…For soils with potassium deficiencies, the two most common soil fertilizers used for supplementing potassium are muriate of potash (MOP; more commonly referred to as potassium chloride or KCl) and sulfate of potash (SOP); more commonly referred to as potassium sulfate or K 2 SO 4 ) (Havlin et al, 1999). United States consumption of KCl was 6,411,121 short U.S. tons in 2014 (USDA/ER, 2019), which would have cost almost 3 billion dollars assuming a 5-year moving average of $500 per metric ton of potassium chloride (KCl) in the U.S. (Yager, 2016).…”