Preparation and properties of potassium alginate soil conditioner microspheres coated with poly(N-isopropyl acrylamide) microgel membrane

Traditional soil conditioners can keep water and release nutrients, and own beneficial effects on plants. However, they show no long-termed effect and cannot achieve the purpose of sustained release that may result in unnecessary economic losses. Soil conditioners prepared from biodegradable macromolecules, inorganic porous material and temperature-responsive microgel can reduce or eliminate these negative effects. In this work, a new type of poly(N-isopropyl acrylamide)/alginate/attapulgite-fulvic acid (PNIPAM/PAL/ATP-FA) soil conditioner microspheres with temperature sensitive properties was prepared. The characterization tests illustrated that the core-shell structure of these microspheres was conducive to the sustained release of fertilizers (63.5 %, for 368 h), and exhibited excellent biodegradability (31.3 %, for 90 days). In addition, the introduction of PNIPAM prolonged the initial outbreak period of the drug. In the pot experiment, they showed good temperature sensitivity at 35 °C, effectively promoting the development and growth of wheat roots (18.3 cm, for 18 days). The outstanding sustained release ability, biodegradability and temperature sensitivity owned by these microspheres illustrate that they have great potential value in agricultural production.