Controlled root targeted delivery of fertilizer using an ionically crosslinked carboxymethyl cellulose hydrogel matrix

Abstract

AimsThe recent increases in food prices caused by the corresponding increases in fertilizer costs have highlighted the demand for reducing the overuse of fertilizers in industrial agriculture. There has been increasing interest in developing plant root-targeted delivery (RTD) of fertilizers in order to address the problem of inefficient fertilizer use. The aim of this study is to develop a low cost controlled release device to deliver fertilizers to plant roots and thereby increase fertilizer use efficiency.MethodsThe Root Targeted Delivery Vehicle (RTDV) is formed by dissolving Carboxymethyl Cellulose (CMC) chains in water, mixing it with liquid fertilizer and crosslinking using iron and calcium salts. Basic measurements quantifying nutrient release and green house growth trials were carried out to evaluate fertilizer use efficiency on wheat growing in nutrient depleted soil media.ResultsGrowing wheat in nutrient depleted media showed that the RTDV permits a 78% reduction in the amount of fertilizer needed to achieve similar levels of plant yield in these conditions. Quantifying the losses associated with the RTDV synthesis showed that optimizing manufacturing could possibly increase this value as high as 94%. Furthermore, the delivery device showed a similar lifetime in soil to the plant’s growth cycle, delivering fertilizer over the course of the plant’s growth before removal from soil by degradation.ConclusionsThese results illustrate the importance of fertilizer delivery in facilitating absorption and may have potential to vastly increase the use efficiency of fertilizers in soil, resulting in a significant reduction of costs and environmental damage. With more in depth study to quantify the fertilizer release and refine the device, there is great potential for the use of the RTDV as an effective means to increase fertilizer use efficiency in agriculture.

Superabsorbent hydrogels based on polysaccharides for application in agriculture as soil conditioner and nutrient carrier: A review

“…It has been reported that calcium ions can drastically decrease the swelling capacity for a hydrolyzed starch-and polyacrylonitrilegrafted copolymer, due to the complexing ability of the carboxylate groups, inducing the formation of intra-and intermolecular complexes [140,141]. Then, depending on the chemically SH network, significant effect is observed on absorption capacity of water, and consequently, on the adsorption capacity of agricultural nutrients [142]. Cations from saline solutions compete with nutrient ions by the active sites inside the 3D hydrogel structure [137].…”

“…Controlled nutrient release from biodegradable chemical hydrogels have been widely studied all over the world [108,133,135,142,144,145]. Controlled nutrient release from polysaccharide-based SH, as carriers, improved the functional efficiency of nutrients, herbicides, insecticides and fungicides, decreasing the cost of the application process, toxicity for humans and environmental pollution [144].…”

“…The most important and essential nutrients for planting soils include potassium, calcium, iron, copper, nitrogen, phosphorus, sulfur and boron [146], although it is estimated that from 40% to 70% of nitrogen and 50% to 70% of potassium are lost by leaching [147]. Thence, high quantities of nutrient are not absorbed by plant roots [142]. In order to solve this problem, additional doses of nutrients, herbicides, insecticides and fungicides need to be applied.…”

Chemically Modified Natural Polysaccharides to Form Gels

“…Naturally it is fully water soluble and usually does not form a hydrogel. CMC, however, has the capacity to form hydrogels by ionic interaction with multivalent cations such as iron (III) and calcium (Yakup Anca 2000;Davidson et al 2013). Additionally CMC (Rokhade et al 2006), divinyl sulfone (Sannino et al 2004), and diepoxies (Kono et al 2013), as well as with interaction with radiation (Wach et al 2001) and other methods.…”

Cassava starch‐graft‐poly(acrylonitrile)‐coated urea fertilizer with sustained release and water retention properties

“…has reported hydroxyethyl cellulose cross‐linked with borax as a matrix for the slow delivery of urea and liquid NP fertilizers. Davidson et al . reported the development of a controlled root targeted delivery fertilizer using ionically cross‐linked carboxymethyl cellulose hydrogel matrix with increased fertilizer use efficiency.…”