The invention discloses a seaweed-based composite water-soluble
fertilizer and a preparation method thereof, and belongs to the technical field of functional fertilizers, gel microspheres embedded with
bacillus subtilis are adsorbed and fixed through a composite seaweed carbon porous carrier, so that the gel microspheres have a good slow-release effect, seaweed belongs to a renewable marine
biomass resource and is wide in source and relatively low in cost, and the seaweed-based composite water-soluble
fertilizer has a good slow-release effect. Meanwhile, the introduced
bacillus subtilis functional component and
castor oil polyether
polyol are environment-friendly substances, so that the soil residue risk caused by
chemical synthesis of an additive is avoided; the seaweed-based composite water-soluble
fertilizer can achieve accurate release, on one hand, due to the water absorption swelling effect of the gel microspheres, release of
bacillus subtilis in the gel microspheres can be promoted; on the other hand, the
metal complex serving as the bridge is PH responsive, and can be matched with
organic acid secreted by microorganisms in the soil in acid soil to promote structural collapse of the
metal complex, so that the gel microspheres rapidly fall off and are released.