Land use change influences soil C, N, and P stoichiometry under 'Grain-to-Green Program' in China.

Zhao Fazhu,Deng Jian,Han Xinhui,Kang Di,Sun Jiao,Feng Yongzhong,Yang Gaihe,Ren Guangxin,Ren Chengjie

doi:10.1038/srep10195

Zhao Fazhu, Deng Jian + Show 7 more

Open Access

https://doi.org/10.1038/srep10195

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Abstract

Changes in land use might affect the combined C, N and P stoichiometry in soil. The Grain-to-Green Program (GTGP), which converts low-yield croplands or abandoned lands into forest, shrub, and/or grassland, was the largest land reforestation project in China. This study collected the reported C, N and P contents of soil in GTGP zones to achieve the factors driving the changes in the C:N, C:P, and N:P values. The results showed that the annual average precipitation exerted significant effects on the C:P value, and on the N:P value became significant 20 years after the change in land use. The annual average temperature was the main factor affecting the C:N value during the first 10 years, while the annual average precipitation strongly affected this value afterwards. In addition, “Redfield-like” interactions between C, N, and P in the soil may exist. A linear regression revealed significant positive correlations between the C:N, C:P, and N:P values and the restoration age, temperature, and precipitation after a change in land use. Therefore large-scale changes in land use under the ‘GTGP’ program might significantly affect the C:N, C:P and N:P ratios in soil.

Highlights

Elements and their ratios in environments affect organisms, while organisms could affect the elemental compositions in their environments by absorbing or releasing different elements[1]
Tian et al reported that the P supply in soil depends on the total P content and the weathering stage of the parent material, which is characterized by spatial heterogeneities[19]
More than 9.27 million ha of cropland and abandoned land have been afforested in China through the “Grain to Green Program” (GTGP), which has required more than 28.8 billion USD and involved 0.12 billion farmers; the Grain-to-Green Program (GTGP) has implemented large-scale ecological rehabilitation since 199922

Summary

Introduction

Elements and their ratios in environments affect organisms, while organisms could affect the elemental compositions in their environments by absorbing or releasing different elements[1]. Cleveland and Liptzin[12] reported that the C, N, and P stoichiometry in soil remains relatively stable at 186:13:1 on the global scale. More than 9.27 million ha of cropland and abandoned land have been afforested in China through the “Grain to Green Program” (GTGP), which has required more than 28.8 billion USD and involved 0.12 billion farmers; the GTGP has implemented large-scale ecological rehabilitation since 199922. This is the first and most ambitious “payment–for–ecosystem–services” program in China[22,24]. This study aims to accomplish the following: a) illustrate the distribution of the soil C:N, C:P, N:P values under the GTGP; b) establish the changes in the soil C:N, C:P, N:P values after the change in land use; and c) study the factors driving the changes in the C:N, C:P, N:P ratios

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