Chronofunctions of Heilu soil developed from Loess in Luochuan, on the chinese Loess plateau

Abstract

SUMMARYSoil chronofunctions are an alternative for the quantification of soil-forming processes and underlie the modeling of soil genesis. To establish soil chronofunctions of a Heilu soil profile on Loess in Luochuan, selected soil properties and the 14 C ages in the Holocene were studied. Linear, logarithmic, and thirdorder polynomial functions were selected to fit the relationships between soil properties and ages. The results indicated that third-order polynomial function fit best for the relationships between clay (< 0.002 mm), silt (0.002-0.02 mm), sand (0.02-2 mm) and soil ages, and a trend of an Ah horizon ocurrence in the profile. The logarithmic function indicated mainly variations of soil organic carbon and pH with time (soil age). The variation in CaCO 3 content, Mn/Zr, Fe/Zr, K/Zr, Mg/Zr, Ca/Zr, P/Zr, and Na/Zr ratios with soil age were best described by three-order polynomial functions, in which the trend line showed migration of CaCO 3 and some elements. Index terms:14 C age, soil properties, element migration, soil development.(

Comparison of Two RUSLE Models at the Hillslope Scale in Experimental Plots in Haiyuan, Ningxia, China

“…The natural vegetation in the region is dominated by grasses and shrubs, though areas used for agriculture vary (Quan et al 2011, Wei et al 2010. The soil is primarily loess, identified as a Heilu black soil, with a hilly, varied topography (Liu et al 2011, Zheng 2006. The FAO-UNESCO classification is Calcic Yermosols (Yk), which are characterized by having a very weak ochric A horizon and an aridic moisture regime, lacking permafrost within 200 cm of the surface (Fullen et al 1995, FAO 2014.…”