One of the biggest problems of any agricultural product, but especially fertilizer, is run-off. That’s a lot of time, crop assistance, and money that simply doesn’t make it to the plant, and instead pollutes nearby eco-systems. But now a team of agrichemical researchers claims to have made a major breakthrough by coating the urea the plant needs onto nano-particles of an organic mineral called hydroxyapatite. Early field results on rice indicate that the method can halve fertilizer usage through the technique’s slow release system.
The online journal, ScienceDaily, outlined the problem, stating that, “Farmers often use urea, a rich source of nitrogen, as fertilizer. Its flaw, however, is that it breaks down quickly in wet soil and forms ammonia. The ammonia is washed away, creating a major environmental issue as it leads to eutrophication of water ways and ultimately enters the atmosphere as nitrogen dioxide, the main greenhouse gas associated with agriculture. This fast decomposition also limits the amount of nitrogen that can get absorbed by crop roots and requires farmers to apply more fertilizer to boost production.”
While coating nano-particles with chemicals has been known by chemical engineers as a useful tool for a long time, until now the method has largely been confined to the pharmaceutical industry. However, little research has been done to use it as a way to apply chemicals to crops, which is surprising given the global expenditure on fertilizer and the problems much of the third world, often living on land that needs fertilizer the most, has in buying sufficient agricultural products.
But now a team has outlined the revolutionary process in a press release to the American Chemical Society, which states how, “The researchers developed a simple and scalable method for coating hydroxyapatite (HA) nanoparticles with urea molecules. HA is a mineral found in human and animal tissues and is considered to be environmentally friendly. In water, the hybridization of the HA nanoparticles and urea slowly released nitrogen, 12 times slower than urea by itself.”
The full report has now been published in the journal ACS Nano, which explains how in the study, “the high solubility of urea molecules has been reduced by incorporating it into a matrix of hydroxyapatite nanoparticles. Hydroxyapatite nanoparticles have been selected due to their excellent biocompatibility while acting as a rich phosphorus source. In addition, the high surface area offered by nanoparticles allows binding of a large amount of urea molecules. The method reported here is simple and scalable, allowing the synthesis of a urea-modified hydroxyapatite nanohybrid as fertilizer having a ratio of urea to hydroxyapatite of 6:1 by weight. Specifically, a nanohybrid suspension was synthesized by in situ coating of hydroxyapatite with urea at the nanoscale. In addition to the stabilization imparted due to the high surface area to volume ratio of the nanoparticles, supplementary stabilization leading to high loading of urea was provided by flash drying the suspension to obtain a solid nanohybrid. This nanohybrid with a nitrogen weight of 40% provides a platform for its slow release.”
It is this slow release that allows the Sri Lankan based team to report that, “Initial field tests on rice farms showed that the HA-urea nanohybrid lowered the need for fertilizer by one-half.”
The research was based on the team’s earlier work from 2011, which had already established the potential success of a system where, “urea-modified hydroxyapatite nanoparticles were encapsulated under pressure into cavities of the soft wood of Gliricidia sepium.” This “urea-modified HA nanoparticle-encapsulated Gliricidia sepium nanocomposite” was then applied to the soil and gave a more effective release of nitrogen than the control commercially available fertilizer. As shown in the graphic below.
You can download a copy of this earlier 2011 study on pdf here.
While it is still too early to claim that global fertilizer sales can be expected to be halved, the research is finding significant interest among agricultural specialists. Seemingly the process is easily scalable, and the new product applicable to all major crops. The technique also includes the added bonus that using Hydroxyapatite will act as a source of phosphorous.
Further testing is now required, before all parties are satisfied of the success of the method. But if it is verified that the process leads to a 50% reduction in fertilizer use, then all agrichem dealers and urea traders might be asking is, “Can I double the price?”