An overview of natural soil amendments in agriculture

This manuscript describes the natural soil amendments used in agriculture, which are divided into three groups: organic, organic-mineral, and mineral amendments. It also describes less popular agents, such as clay minerals, sewage sludge, and amendments based on slaughterhouse wastes. A specific group of organic amendments are algae-base amendments which are becoming more and more popular. The soils most improved with natural amendments include sandy loam and clay soils. Natural organic amendments are best used on light soils that are poor in organic matter and nutrients (NPK). Whereas mineral amendments can be used as fertilizers (provide mainly Si, Ca and Al) or to restore degraded soils. Based on the analyzed literature, natural soil amendments may well be considered as an alternative to synthetic agricultural agents.