Water resource shortage, low fertilizer use efficiency, and environmental degradation are major challenges confronted by global agriculture and threatens the ecological environment, while there remains little research on achieving a combination of sustained nutrient release and pollution impact assessment. Taking biomass waste collagen (leather waste) as a tailor-made intrinsic nitrogen resource, we prepared a cost-effective and eco-friendly biodegradable protein-based hydrogel with the ability of nutrient controlled-release and heavy metal adsorption. Specifically, the as-prepared biofertilizer exhibited good biodegradability in soil, which can be a carbon source for supporting the growth of Ensifer sp.Y1. Furthermore, the as-prepared biofertilizer shows a high water absorbency capacity of 2208 g g^-1, as well as preferable controlled-release nitrogen and potassium fertilizer for more than 40 days. Meanwhile, the multifunction of hydrogel was evaluated simultaneously for heavy metal adsorption in simulating contaminated by Cr (III) under all kinds of environmental parameters, and the hydrogel exhibited excellent adsorption capacity of 149.3 g g^-1 for Cr (III). Therefore, this easy and efficient process opens up a new avenue to develop integrated output-increasing techniques through a circular economy for soil pollution control and wastewater treatment.

水资源短缺、化肥利用效率低、环境恶化是全球农业面临的主要挑战，威胁着生态环境，而实现养分持续释放和污染影响评估相结合的研究还很少。以生物质废弃物胶原蛋白（皮革废弃物）为特制的内在氮资源，我们制备了一种具有营养控释和重金属吸附能力的低成本、环保的可生物降解蛋白质基水凝胶。具体而言，所制备的生物肥料在土壤中表现出良好的生物降解性，可以作为支持Ensifer sp.Y1生长的碳源。此外，所制备的生物肥料显示出 2208  g的高吸水能力 g ^-1，以及40天以上的优选控释氮和钾肥。同时，在各种环境参数下模拟Cr(III)污染，同时评估了水凝胶对重金属吸附的多功能性，该水凝胶对Cr(III)表现出149.3  g  g ^{-1 的}优异吸附能力。因此，这种简单高效的过程为通过循环经济开发用于土壤污染控制和废水处理的综合增产技术开辟了新途径。