Preparation of a honeycomb-like magnetically controlled release straw-based fertilizer

Abstract

It is significant to improve fertilizers utilization efficiency (UE), realize the recycling of straw, and transform the traditional fertilization mode for fruit trees (ditch or hole). Therefore, a honeycomb-like magnetically controlled-release fertilizer (HMCRF) was prepared by combining corn straw (CS), urea, Fe3O4, modified starch adhesive (MSA), and amino silicone oil (ASO) in this work. CS served as a carrier for urea, MSA was an environmentally friendly adhesive, and Fe3O4 acted as a magnetic-sensitive material. The hydrogen bonds that exist among CS (-OH), urea (-NH2), and Fe3O4 (-FeO) played an essential role in urea adsorption. The magnetic field could effectively control the release of urea and improve urea UE. Thus, fertilizers could be provided to fruit trees according to their nutrient requirements at different growth stages to reduce waste. What's more, HMCRF could be applied directly on the soil surface, which not only saved labor but also differed from the traditional application method. The honeycomb-like structure was also favorable for rainwater storage and urea release in practice. Notably, HMCRF had a high biosafety on earthworms and could significantly boost the amount of beneficial microorganism in soil. The study offers a novel controlled-release fertilizer to promote urea UE, reduce labor, and achieve CS recycling.