Effect of soil coarseness on soil base cations and available micronutrients in a semi-arid sandy grassland

Linyou Lü,Guoqing Yu,Jinfei Yin,Zhengwen Wang,Ruzhen Wang,Xingguo Han,Yong Jiang,Heyong Liu,Yan Zhao,Jiangtao Xiao

doi:10.5194/se-7-549-2016

Abstract

Abstract. Soil coarseness is the main process decreasing soil organic matter and threatening the productivity of sandy grasslands. Previous studies demonstrated negative effect of soil coarseness on soil carbon storage, but less is known about how soil base cations (exchangeable Ca, Mg, K, and Na) and available micronutrients (available Fe, Mn, Cu, and Zn) response to soil coarseness. In a semi-arid grassland of Northern China, a field experiment was initiated in 2011 to mimic the effect of soil coarseness on soil base cations and available micronutrients by mixing soil with different mass proportions of sand: 0 % coarse elements (C0), 10 % (C10), 30 % (C30), 50 % (C50), and 70 % (C70). Soil coarseness significantly increased soil pH in three soil depths of 0–10, 10–20 and 20–40 cm with the highest pH values detected in C50 and C70 treatments. Soil fine particles (smaller than 0.25 mm) significantly decreased with the degree of soil coarseness. Exchangeable Ca and Mg concentrations significantly decreased with soil coarseness degree by up to 29.8 % (in C70) and 47.5 % (in C70), respectively, across three soil depths. Soil available Fe, Mn, and Cu significantly decreased with soil coarseness degree by 62.5, 45.4, and 44.4 %, respectively. As affected by soil coarseness, the increase of soil pH, decrease of soil fine particles (including clay), and decline in soil organic matter were the main driving factors for the decrease of exchangeable base cations (except K) and available micronutrients (except Zn) through soil profile. Developed under soil coarseness, the loss and redistribution of base cations and available micronutrients along soil depths might pose a threat to ecosystem productivity of this sandy grassland.

Highlights

Dryland ecosystems, accounting for 41 % of the total land area of the world, are prone to desertification which would result in soil coarseness (Cerdà et al, 2014; T. Wang et al, 2015)
Soil coarseness significantly increased soil pH by up to 8.8 % across three soil depths (Fig. 2a; Table 2). For both 0–10 and 10–20 cm soils, the highest soil pH was detected in C70 (7.3 and 7.4, respectively) and C50 (7.2 and 7.3, respectively) soils, which were followed by C30 and C10 soils (Fig. 2a)
Significant interactive effect of soil coarseness and soil depth was found on soil pH (Table 2)

Summary

Introduction

Dryland ecosystems, accounting for 41 % of the total land area of the world, are prone to desertification which would result in soil coarseness (Cerdà et al, 2014; T. Wang et al, 2015). Dryland ecosystems, accounting for 41 % of the total land area of the world, are prone to desertification which would result in soil coarseness Dryland ecosystems represent 25 % of land surface area in Latin America, with 75 % of them having desertification problems (Torres et al, 2015). Desertified land area has been reported to reach 45.6 million km (Torres et al, 2015) and account for 74 % of total dryland area (61.5 million km2), with more than 100 countries and 8.5 × 108 people being affected Desertification was reported to cause economic losses of up to EUR 6 billion in Northern China in the year 2005 (Miao et al, 2015)

Methods

Results

Discussion

Conclusion