Outputs: Potassium Losses from Agricultural Systems

Abstract

Potassium (K) outputs comprise removals in harvested crops and losses via a number of pathways. No specific environmental issues arise from K losses to the wider environment, and so they have received little attention. Nevertheless, K is very soluble and so can be leached to depth or to surface waters. Also, because K is bound to clays and organic materials, and adsorbed K is mostly associated with fine soil particles, it can be eroded with particulate material in runoff water and by strong winds. It can also be lost when crop residues are burned in the open. Losses represent a potential economic cost to farmers and reduce soil nutritional status for plant growth. The pathways of loss and their relative importance can be related to: (a) the general characteristics of the agricultural ecosystem (tropical or temperate regions, cropping or grazing, tillage management, interactions with other nutrients such as nitrogen); (b) the specific characteristics of the agricultural ecosystem such as soil mineralogy, texture, initial soil K status, sources of K applied (organic, inorganic), and rates and timing of fertilizer applications. This chapter provides an overview of the main factors affecting K removals in crops and losses through runoff, leaching, erosion, and open burning.

Influence of farmers’ socio-economic characteristics on nutrient flow and implications for system sustainability in smallholdings: a review

“…Nonetheless, N is the most required nutrient by plants and the most mobile nutrient, making it easily lost from the soil through harvested products, leaching, volatilization, erosion, and denitrification if not managed properly (88,139). Potassium, on the other hand, is the third most important nutrient for crops after phosphorus (140). Despite the fact that potassium is abundant in soils, the readily available pool is so small, and the fate of K in soil is almost similar to that of N (141).…”

Assessment of Soil Chemical Properties for Monitoring and Maintenance of Soil Fertility in Probolinggo, Indonesia

“…It is often bound to clay and other organic substances, and it mostly gets absorbed when attached to fine soil particles. As such, K is prone to erode to rain or wind exposure [88]. Soil typically erodes more in harder rain [89] and harder wind [90].…”

Taxonomic and Functional Diversity of Aquatic Macroinvertebrate Assemblages and Water Quality in Rivers of the Dry Tropics of Costa Rica

“…It is usually found in natural surface waters under 5 mg/L (Skowron et al, 2018) and between 2 and 3 mg/L in rivers (Lenntech, 2020); the values found in both rivers are higher than that, indicating the use and pollution of freshwater by artificial fertilizers with the Las Palmas river showing higher potassium values than the Colorado river (Table 1). Potassium can be used as an indicator of surface runoff because it is very soluble and can be washed by rainfall into water bodies depending on rainfall intensity and unlike nitrogen, there are no gaseous losses of potassium (Alfaro et al, 2008;Alfaro et al, 2017;Goulding et al, 2020). This potassium runoff is exceptionally high in tropical regions (Acharya et al, 2007).…”