Construction of heilu soil chronofunction in Luochuan, China

Soil chronofunction is an important way to understand soil forming processes quantificationally, and the foundation for establishment of soil genesis model. To establish soil chronofunction, soil properties and ¹⁴C ages in the Holocene of heilu soil profile in Luochuan were researched. Linear, logarithmic, and third order polynomial functions were selected to fit the relationships between soil properties and soil ages. The results indicated that, third order polynomial function was the best to fit the relationships between clay (<;0.002 mm), silt (0.002-0.02 mm), sand (0.02-2 mm) and soil ages, and the trend line showed the presence of Ah horizon in the profile. The logarithmic function indicated the variation of soil organic carbon and pH with time perferably. The variation of CaCO₃ content, Mn/Zr, Fe/Zr, K/Zr, Mg/Zr, Ca/Zr, P/Zr, and Na/Zr with soil age could be described best by use of three order polynomial functions, and the trend line showed migration of CaCO₃ and soil elements.