Abstract

Karst rocky desertification (KRD) is a global environmental degradation problem caused by human activities and vegetation deterioration. Vegetation restoration in KRD is very difficult due to severe water loss, soil erosion and extensive bare bedrock. For achieving vegetation restoration on bare bedrock areas of KRD, the nutrient medium technique was developed, which is based on the special hydro-geological conditions that is seasonal rainfall is abundant in Karst region of Southwest China and limestone fissures are extremely developed and rich in fissure water. The objective of this research is to investigate the feasibility of using nutrient medium technique to achieve vegetation restoration in KRD region. Through the indoor and field experiments, some properties of the nutrient medium mixture were tested, including water retention, water absorption and nutrient retention. The results showed that the moisture content on the 75th day and water absorption rate of No.2 mixture was 19.9% and 1.67 mm/d, respectively, which could be used as optimum mix ratio for producing nutrient medium. The field results showed that the nutrient medium technique could effectively guarantee the survival of sapling at early age and sustainable growth at later age in the field, and the nutrient medium had less nutrient loss. This novel approach can retain and absorb moisture, and saplings do not need artificially supply water and fertiliser in the dry season, and the use of nutrient medium technique to achieve vegetation restoration in KRD region seems to be a feasible option.

Highlights

  • Karst rocky desertification (KRD) is utilised to characterise the processes that transform a Karst region covered by vegetation and soil into a rocky landscape almost devoid of soil and vegetation (Gao et al 2013; Wang et al 2004), which is one major type of desertification caused by human impacts on the vulnerable eco-geo-environment

  • The results showed that the seedlings height increased firstly and decreased with increasing in mushroom residue (MR) content

  • The addition of cow dung compost (CDC) in the mixture exceeded 10% had a significant effect on seedlings height, while the increased in seedlings height after adding more than 15% CDC was not significant

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Summary

Introduction

Karst rocky desertification (KRD) is utilised to characterise the processes that transform a Karst region covered by vegetation and soil into a rocky landscape almost devoid of soil and vegetation (Gao et al 2013; Wang et al 2004), which is one major type of desertification caused by human impacts on the vulnerable eco-geo-environment KRD is a global phenomenon of environmental degradation that is mainly distributed in European Mediterranean basin (Mauro et al 2012), the Dinaric Karst (Gams and Gabrovec 1999) and Southwest China (Yuan 1997). KRD landscapes are widely found in other countries or regions of the world, such as in Belize, Guatemala, Mexico of North America, Israel of the Middle East, East and south-east of Asia, including the Ryukyu Islands of Japan and Gunung Sewu of Indonesia (Ford and Williams 2007). Karst landscape in southwest China is one of the most archetypal landscapes developed on limestone in the world (Liu 2009). KRD region in Southwest China is one of the most concentrated Karst areas in the world, which mainly includes seven provinces (or municipalities) of Guizhou, Yunnan, Sichuan, Guangxi, Guangdong, Hunan, Hubei and Chongqing

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