Biological nutritional agent and preparation method thereof

The invention discloses a biological nutritional agent and a preparation method thereof. The biological nutritional agent comprises the following components in parts by weight: 0.001-0.1 of brassinolide, 1.0-5.0 of magnesium sulfate, 1.0-6.0 of zinc sulfate, 1.0-5.0 of manganese sulfate, 1.0-5.0 of sodium tetraborate, 1.0-15.0 of glucose and 5.0-30.0 of calcium lactate. The preparation method comprises the following steps of: dissolving the brassinolide by using a cosolvent, adding an emulsifier for uniformly mixing, and preparing a brassinolide emulsion for later use; adding purified water into a blending device, sequentially adding a chelant and a suspending agent, stirring and mixing uniformly, sequentially adding the magnesium sulfate, the zinc sulfate, the manganese sulfate, the sodium tetraborate, the glucose and the calcium lactate in the stirring process; homogenizing for 20min, and then adding a film-forming agent; dropwise adding the brassinolide emulsion into the blending device in the homogenizing process, and regulating uniformly to obtain the biological nutritional agent. The biological nutritional agent prepared by the invention has the advantages of being convenient to use and safe and ensuring the effective growth of plants.