Role of Cation Substitution and Synthesis Condition in a Calcium Phosphate-Based Novel Nanofertilizer on Lettuce (Lactuca sativa) Yield

Abstract

Hydroxyapatite nanoparticles (HANPs) have received increasing attention as a potential novel fertilizer. Although stoichiometric HANPs have limited solubility, they can be tuned for more controlled phosphorus (P) release applications. To enhance the dissolution for maximizing P delivery to plants, we synthesized HANPs and dicalcium phosphate anhydride (DCPA) under varying crystallization conditions (temperature, pH, and cation substitution). The efficacy of these materials in improving lettuce (Lactuca sativa) yield was investigated in the greenhouse. Comparative analyses of shoot and root biomass, tissue nutrient content, and P loss in the leachate show that all HANPs and DCPA stimulated lettuce growth, but the extent of enhancement was a function of synthesis condition. Lettuce fertilized with DCPA, a more soluble Ca–P product, showed two times higher crop yield than controls, but P loss in leachate was the highest. On the other hand, lettuce fertilized with HANPs synthesized at pH 7.0 resulted in a 73% greater crop yield than the control, and the P loss to leachate was lowest among all Ca–P products tested. Considering the 'green' efficiency that accounts for both promoting plant growth and limiting P loss, HANP synthesized at pH 7.0 is found to be more optimal. These results demonstrate that tuning the properties of HANPs is an effective approach to optimize P release to enhance crop yield and minimize P loss. These outcomes also provide a scientific basis for developing tunable nanofertilizers specific to a crop or soil condition and, thus, a sustainable approach toward meeting global food demands while simultaneously minimizing the negative environmental impacts of agriculture.

Citrate-Stabilized Amorphous Calcium Phosphate Nanoparticles Doped with Micronutrients as a Highly Efficient Nanofertilizer for Environmental Sustainability

“…17−20 Calcium phosphate (CaP) nanoparticles are one of the candidate fertilizers because they can be synthesized with tailored properties with optimal P release kinetics and exhibit high fertilization efficiency. 13 Furthermore, CaP can be a carrier of vital micronutrients for the simultaneous delivery to plants. Among CaP phases, amorphous calcium phosphate (ACP) is the material of great interest due to its ability to incorporate multiple doping elements.…”

“…The price hike and increasingly growing public awareness of a healthy environment, including wider enforcement of the U.S. Environmental Protection Agency (US EPA)’s Clean Water Act, have generated great interest in the development of products that can address both economic and environmental concerns. Among the current efforts, the development of fertilizers that have dual functions enhance agricultural production while simultaneously minimizing P loss from agricultural fields , is among the most sustainable pathways for long-term agricultural and environmental stewardship. One of the approaches to achieve both goals is the development of nanofertilizers (which could be in colloidal form), which allow precision tuning of their chemical properties and modulating their nutrient release at desired spatial and temporal scales. − …”

“…Calcium phosphate (CaP) nanoparticles are one of the candidate fertilizers because they can be synthesized with tailored properties with optimal P release kinetics and exhibit high fertilization efficiency . Furthermore, CaP can be a carrier of vital micronutrients for the simultaneous delivery to plants.…”

Nutrient-Doped Hydroxyapatite: Structure, Synthesis and Properties

“…Their use results in substantial P losses due to leaching and surface run-off, which present challenges to food security and environmental sustainability [14]. The use of less soluble P forms, such as phosphate rocks and apatite, can mitigate these losses and also show P availability for plants [15,16]. Exploring the potential of nanoscale inorganic powdered materials, such as HAP, offers a promising avenue, albeit necessitating thorough and systematic investigations of the complex multi-component system synthesis techniques and the resulting fundamental properties.…”