Microencapsulated soil conditioner with a water-soluble core: improving soil nutrition of crop root

Abstract

Traditional level of fertilisers was used by most farmers in China with the risks about resources wasting, environmental pollution together with soil structure deterioration. It is practicable to tackle the challenges about over-fertilisation and low efficiency with microencapsulated soil conditioner (MSC), which clads the water soluble core with natural polymer. Fulvic acid (FA) can be used as core material, because it possesses the characteristics of water-soluble, fertiliser maintenance and expedient monitoring. The morphology, structure, and properties of MSC were studied and compared. The particle size of MSC was ranged from 1.58 to 2.14 mm with a similar shape which was obtained by conventional measuring method due to their soft features. This was mainly attributed to the concentration of liquid paraffin and the interaction between shell materials and calcium chloride. FTIR spectra showed that a peak appeared at 1372 cm−1, and this was ascribed to the microcapsules crosslinked and solidified by calcium ions. Sustained release experiment revealed that the microcapsules owned better fertiliser-retaining and water-retaining performances, and FA may be released as long as 750 h. Biodegradation experiments revealed that an obvious pore structure was found on the surface of microspheres after 30 d of degradation, and this was consistent with the sustained release experiment. Pot experiment illustrated that the plants cured with the microcapsules showed significant growth trend and grew up to 9.2 cm with a maximum rate, and this revealed that MSC owned better performance of promoting the growth of crop root.