Abstract
The staggering production of rock dusts and quarry by-products of mining activities poses an immense environmental burden that warrants research for value-added recycling of these rock mineral powders (RMP). In this study, an incubation experiment was conducted to determine potassium (K) and micronutrients (Zn, Cu, Fe and Mn) release from a quarry RMP to support plant nutrition. Four different size fractions of the RMP were incubated with organic amendments (cow dung and legume straw) under controlled conditions for 90 days. Samples were collected at different intervals (7, 15, 30, 45, 60 and 90 days) for the analysis of available K and micronutrients in the mineral-OM mixtures and leachates. There was a significant (p <0.05) increase in pH of leachates from the mineral-OM mixtures. The K release was significantly higher from the finer size fraction of RMP. About 18.7% Zn added as RMP was released during the incubation period. Zn release increased from 4.7 to 23.2% as the particle size of RMP decreased. Similarly, Cu release from RMP increased from 2.9 to 21.6%, with a decrease in the particle size. Fe and Mn recovery from RMP recorded 11.2 and 6.6%, respectively. Combined application of OM and RMP showed significantly higher nutrient release than other treatments. This study indicates that effective blending of RMP with organic amendments could be a potential source of K and micronutrients in agriculture without posing a risk of toxic element contamination to the soil.
Highlights
Limited supply of potassium (K) and micronutrients (e.g., Zn, Cu, Fe, Mn) is the most prevalent constrain for plant growth worldwide, especially in organic agriculture where the nutrient supply to crops is mainly derived from mineralization/decomposition of native and/or introduced organic sources and natural weathering of soil minerals (Torma et al 2018)
Since synthetic sources are not allowed in organic cultivation system, the demand of nutrients is to be met by alternative sources such as organic materials and locally available geological materials (Manning 2018)
Results of this study suggested that the rock mineral powders (RMP) contained significant amounts of K (1.54% total K) and supplied essential micronutrients (Zn, Cu, Fe and Mn) when used in combination with organic materials
Summary
Limited supply of potassium (K) and micronutrients (e.g., Zn, Cu, Fe, Mn) is the most prevalent constrain for plant growth worldwide, especially in organic agriculture where the nutrient supply to crops is mainly derived from mineralization/decomposition of native and/or introduced organic sources (e.g., manures and crop residues) and natural weathering of soil minerals (Torma et al 2018). The nutrient requirements in organic agriculture may be externally met by the application of less soluble sources such as manures, crop residues and rock mineral powders (RMP) (Basak and Sarkar 2017). Since synthetic sources are not allowed in organic cultivation system, the demand of nutrients is to be met by alternative sources such as organic materials and locally available geological materials ( termed as agro-minerals) (Manning 2018). It is imperative to find alternative sources that meet the guidelines of organic cultivation systems
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
