From manure to high-value fertilizer: The employment of microalgae as a nutrient carrier for sustainable agriculture

The use of livestock and poultry manures as fertilizers is regarded as an important action in the development of circular agriculture. However, long-term fertilization with manure is accompanied with heavy metals accumu-lation, pathogens contamination, and ammonia toxicity, which may cause the decline of soil quality and crop productivity. To address the aforementioned problems, in this work, we proposed a manure-algae-crop tech-nical route, in which microalgae are employed as a carrier transporting nutrients in manures to soil and crops. This paper presented the advanced techniques which can tackle with the hazardous factors in manures and promote the nutrients assimilation by microalgae. Additionally, the utilization of microalgae in the forms of living cyanobacteria, liquid fertilizer, and slow-release fertilizer was discussed in detail. Particularly, we also focused on the disadvantages of algae fertilizers in different forms. By the end of this work, based on the analysis of current challenges and problems, we discussed the potential solutions and prospects of manure-algae-crop technical route.In fact, previous studies have achieved many progresses in algae-based manure remediation and utilization of algae fertilizers. Hence, based on current knowledge, manure-algae-crop technical route has greater advan-tages over traditional models of manures utilization in agriculture. In the foreseeable future, with the devel-opment of new technologies, reduction of operational cost, and upgrading of agricultural model, manure-algae -crop technical route will be applied more frequently in agriculture. It is expected that this technical route can truly promote the high-value utilization of manures and the development of eco-friendly agriculture.

Automated summary

This work proposed a manure-algae-crop technical route to address the issues accompanied with long-term fertilization using manure. It introduced advanced techniques to tackle hazardous factors in manures and promote nutrient assimilation by microalgae. Future applications of this technical route in agriculture are expected to promote high-value utilization of manures and eco-friendly agriculture.