Abstract:

To understand the evolution law of soil fertility of red soil reclamation land in low hilly area, we studied the soil quality evolution in the process of reclamation, fertilization and maturation from red soil farmland by the method of replacing time with space. The results showed that: the contents of soil organic matter, total nitrogen, water-stable aggregates, available phosphorus and available potassium decreased significantly at the initial stage of reclamation of wasteland red soil because of the mixing of topsoil and subsoil, but with the increase of fertilization and maturation time, the soil acidity decreased gradually, the base saturation, the organic matter and the ratio of humus to organic matter increased; meanwhile, the contents of water-stable aggregates, total phosphorus, available phosphorus and microbial biomass carbon gradually increased, the soil texture gradually became lighter, and the C/N ratio gradually tended to be stable. Based on the comparative study of the soil fertility and productivity of reclamation cultivated land in different places and at different reclamation times, the following indicators are put forward for soil maturation of reclamation cultivated land in red soil hilly area: the thickness of tillage layer is >15 cm; the structure mainly dominated by small block and cluster; the percentage of >0.25 mm water stable aggregates is >30%; the soil pH value is >5.5 the base saturation is >60%; the soil organic matter content ranges from 15 to 20 g/kg with C/N ratio of 12-17, H/F is >0.40, and the ratio of humic acid and organic matter is >0.30; the soil available phosphorus, available potassium, and microbial biomass carbon are 7.5-30 mg/kg, >75 mg/kg, >75 mg/kg, respectively.

Key words: Reclamation Cultivated Land, Fertility Evolution, Maturation Index, Acidity, Organic Matter, C/N