Structural Analysis of Humic Acid in Soil at Different Corn Straw Returning Modes through Fluorescence Spectroscopy and Infrared Spectroscopy

Table 1

Basic properties of the soil tested in the experiment.

Depth (cm)	Organic carbon (g/kg)	Available N (mg/kg)	Available P (mg/kg)	Available K (mg/kg)	pH
5–20	19.44	78.97	24.08	97.67	6.56
20–40	18.63	69.19	21.31	85.56	6.48