Soil Health Impacts of Rubber Farming: The Implication of Conversion of Degraded Natural Forests into Monoculture Plantations

Thu Thi Nguyen,Tran Vu Khanh Linh,Trang Thanh Pham,Truong Tat Do,Nguyen Xuan Giap,Le Bao Thanh,Thai Son Le,Richard Harper

doi:10.3390/agriculture10080357

Abstract

High revenues from rubber latex exports have led to a rapid expansion of commercial rubber cultivation and, as a consequence, the conversion of different land use types (e.g., natural forests) into rubber plantations, which may lead to a decrease in soil health. In this study in Quang Tri Province, Vietnam, we determined: (1) the variation of soil health parameters along a chronosequence of rubber tree stands and natural forests and (2) the relationships and potential feedback between vegetation types, vegetation structures and soil health. Our results revealed that: (1) soil health was higher in natural forests than in rubber plantations with a higher values in higher biomass forests; (2) soil health was lower in younger rubber plantations; (3) soil health depends on vegetation structure (with significantly positive relationships found between soil health and canopy cover, litter biomass, dry litter cover and ground vegetation cover). This study highlights the need for more rigorous land management practices and land use conversion policies in order to ensure the long-term conservation of soil health in rubber plantations.

Highlights

The rubber tree (Hevea brasiliensis) has been one of the most economically valuable trees among global farming systems for the past three decades [1]
The means of soil health parameters were higher in natural forests than rubber plantations
This study confirmed that the Northern Central Vietnam natural forests have higher values of soil health than that in rubber plantations

Summary

Introduction

The rubber tree (Hevea brasiliensis) has been one of the most economically valuable trees among global farming systems for the past three decades [1]. Many farmers have chosen to convert other land use types (e.g., degraded natural forests or timber plantations) into rubber plantations, which has led to the rapid expansion of rubber plantations worldwide [3,4]. Following the introduction of rubber trees to southern Vietnam in 1897 this economically valuable species has become a major perennial tree in Central and Northern Vietnam [6]. Because of their high economic value, rubber trees have become the priority among targeted trees for the economic

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