Objective  To explore the fertilizer effect of new medium element fertilizer and its mechanism of increasing production.

Method  The synergistic single superphosphate calcium was used to produce medium element coated fertilizer. The synergizing methods included single superphosphate calcium ammonization, humic acid, amino acid and binding agents were added for granulation; After drying, plant growth regulators, biological agents, anti-caking agents and parcel oil were added to coat the fertilizer. The pot experiment of lettuce and the field experiments of rape seed and peanut were carried out. The effect of new fertilizer was verified by analyzing the crop agronomic characteristics and physiological indexes.

Result  The scanning electron microscope (SEM) result showed that the specific coating layer of the new fertilizer played a slow release effect. The energy dispersive spectroscopy (EDS) result showed that the new fertilizer could provide various nutrients such as P, Ca, Mg and S for crops. The lettuce pot experiment showed that the yield of medium element coated fertilizer produced by synergistic single superphosphate calcium increased 10.8%–35.9% than that of common single superphosphate calcium. The field experiments showed that compared with simple synergistic single superphosphate calcium treatment, the medium element coated fertilizer increased the yield of rape seed and peanut by 64.5%–89.7% and 9.2%–11.1%, respectively, and the product efficiency was better than that of calcium-magnesium fertilizer on the market.

Conclusion  Single superphosphate calcium fertilizer produced by synergistic techniques such as ammonization, granulation and coating can promote the absorption of Ca, Mg and S by crops and their transport and distribution efficiency in vivo. This product can be industrialized and brought to market.