Data for Use of vector method to evaluate the effect of land use and soil parent material on aggregate stability in red soil zone of Southern China
Description
As the major limiting factor controlling soil erosion, soil aggregate stability may be closely related to land use and soil parent material in the red soil region of southern China. However, relatively few studies have been conducted to comprehensively synthesize the effects of land use and soil parent materials on the stability of soil aggregates. In view of this, in this study, soil samples of four typical land use types (natural forests, artificial forests, orchards, and slope farmland) and two parent materials (granite and slate) were collected from every 20 cm in soil depth 0-100 cm in Dawei Mountain National Forest Park and Xiaoxi National Forest Park, respectively, which are located in the subtropical red soil zone. And soil aggregate stability was determined by a new approach of vector method to calculate the vector length stability index (VLSI) and its weighted form (wVLSI).
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Steps to reproduce
The vector method was recently proposed by Ma et al. (2024). Unlike the Yoder method, this method does not pre-treat the soil samples (e.g., dry sieving or slow pre-humidification) before wet sieve analysis, leaving them in their original state at the time of collection. The experimental procedure was as follows: 50 g of air-dried soil samples were weighed and placed directly on the sieves of 5 mm, 2 mm, 1 mm, 0.5 mm and 0.25 mm apertures, followed by rapid immersion of the sieve set into a flat-mouthed settling bucket filled with tap water, allowing for the simultaneous analysis of four samples at a time. During wet sieving, the sieve was oscillated up and down at a frequency of 28 times/min and an amplitude of 3.8 cm for 30 min. After that, the soil aggregates on each sieve were rinsed into aluminum boxes. Subsequently, the soil samples were subjected to a drying process at a constant temperature of 60 °C for 48 h. Finally, the mass of each particle size aggregate was determined.The VLSI and wVLSI can be calculated as: VLSI=√(p_1^2+p_2^2+...+p_n^2 ) ∈[0,1] P1+P2+...+Pn ∈[0,1] wVLSI=√(2^(n-1)/2^(n-1) p_1^2+〖2^(n-2)/2^(n-1) p〗_2^2+...+2^(n-n)/2^(n-1) p_n^2 ) where p is the proportion of larger aggregates (particle size >0.25 mm); the sum of p1 to pn lies in the interval [0,1]. When no aggregates are retained on any of the sieves (each with pi=0), the minimum value of VLSI will be 0. Conversely, when all the aggregates are concentrated on one of the sieves (one of them with pi=1), the maximum value of VLSI will be 1, VLSI∈[0,1].