Influence of manure fertilization on soil phosphorous retention and clay mineral transformation: Evidence from a 16-year long-term fertilization experiment

Phosphorus (P) has a deficit effect for living organisms, and there is a continuous influx of large amounts of P fertilizers into agriculture systems. However, the low use efficiency of P fertilizers in the current practice of crop production is attributed to the quick fixation effects of soil minerals on the added P fertilizer. This work investigated the effects of long-term manure fertilization on soil P retention and clay mineral phase transformation using X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM) and energy dispersive X-ray spectroscopy (EDS). The manure application with lime significantly mitigated soil acidification, and P retention was significantly correlated with soil colloids. Microanalysis data revealed that clay minerals, acting as the substrate, likely provided plenty of sites for P retention to support the crystallized and amorphous Fe-oxides, which promoted P adsorption/stabilization. The manure addition led to the transformation of soil clay minerals from 2:1 type to 1:1 type, which was related to soil microbial biomass. Taken together, our study suggest that manure fertilization impacts the microbial biomass, and thereby promotes the transformation of clay minerals and further influences the retention and reactivity of P in the soil environment.

Automated summary

The addition of lime with manure helps mitigate soil acidification and improves the retention of phosphorus, which is closely related to soil colloids. The study demonstrates that manure application leads to the transformation of soil clay minerals, affecting the retention and reactivity of phosphorus in the soil.