Water-soluble fertilizer product prepared from pulping by-product and application of water-soluble fertilizer product

The invention relates to a water-soluble fertilizer product prepared from pulping byproducts and application of the water-soluble fertilizer product, in particular to a process for processing red liquor and black liquor obtained by an acid pulping process and an alkaline pulping process to obtain bio-based water-soluble fertilizers, and the two water-soluble fertilizers mainly comprise macromolecular lignosulfonate and lignin sylvite. The compound fertilizer can be widely applied to commercial crops and field crops in greenhouses, fields, deserts, saline-alkali soil, wasteslopes and the like, and the two products have remarkable effects of increasing the yield and improving the quality, reducing the use of chemical fertilizers, conditioning soil and the like on various field crops, commercial crops, vegetables and fruits. 本发明涉及一种制浆副产物制备的水溶性肥产品及其应用，具体涉及酸法制浆工艺和碱法制浆工艺获得的红液和黑液进行加工处理获得的生物基水溶肥的工艺，两种水溶肥的主要成分为高分子的木质素磺酸盐和木质素钾盐，可以广泛应用于大棚、大田、沙漠、盐碱地、荒坡等的经济作物及大田作物，两种产品对各种大田作物、经济作物、蔬菜水果都具有显著的增产提质，减用化肥、调理土壤等的作用。