Objective The study aims to develop a moisturizing high-adhesion slow-release foliar fertilizer with a semi-interpenetrating polymer network structure and excellent adhesion, water absorption and slow release properties.

Method Polyvinyl alcohol (PVA) and acrylic acid (AA) were used as raw materials to prepare water-absorbent resin, and semi-interpenetrating network technology used to interpenetrate urea aldehyde into the water-absorbing and water-retaining network to prepare moisturizing high-adhesion slow-release foliar fertilizer. The effects of mass ratio of polyvinyl alcohol to acrylic acid (m_PVA/m_AA) and addition amount of cross-linking agent on the water absorption property of foliar fertilizer and the effects of addition amount of water-absorbent resin on the adhesion and slow-release properties of foliar fertilizer were studied.

Result When m_PVA/m_AA is 1 ∶ 2 and the addition amount of cross-linking agent is 0.5%, the prepared foliar fertilizer has the maximum water absorption rate, which is 68.5 g/g in tap water. When m_(PVA+AA)/ m _(Urea) = 2 ︰ 1, the retention rates of nitrogen and phosphorus of foliar fertilizer on cabbage leaves reach 80% and 40%, respectively; the release of nitrogen and phosphorus nutrients of leaf fertilizer achieves balance in 7-10 days, with good slow-release performance.

Conclusion The research is of great significance to solve the problems of poor adhesion, no water absorption, and no slow-release properties of conventional foliar fertilizers.