Simulation on the Future Change of Soil Organic Carbon from Phaeozems under Different Management Practices in Northeast China

Maoxin Zhang,Anping Yun,Minggang Xu,Mingguo Liu,Liping Guo,Jing Zhang,Fawang Ma,Liyong Xie

doi:10.3390/su9071129

Abstract

The Phaeozem region is an important grain production base in China and soil fertility has declined under long-term cultivation. Studying soil organic carbon (SOC) change in the upland phaeozem of Northeast China under different tillage modes has great theoretical and practical significance for reducing greenhouse gases emissions, increasing soil carbon stocks, and ensuring food security. This study applied the DAYCENT model to simulate six long-term experimental sites in the phaeozem region, and through calibration and validation analysis, it concluded that the DAYCENT model could effectively simulate the dynamic change of SOC in the upland phaeozems; hence, the relevant parameters of each site were determined. Under future climate scenarios (Representative Concentration Pathway 4.5, RCP 4.5), SOC change in agricultural soils (0–20 cm topsoil) of four different management scenarios (fertilizer application, manure amendment, straw return, no-tillage) was simulated. The overall simulated trend was no-tillage > straw return > manure amendment > fertilizer application. Fertilizer had no evident effect on increasing SOC, but the effect would be better if combined with manure; both straw return and no-tillage had the general effect of improving SOC and the simulated values rose rapidly with a large increasing rate within a short period; however, the increasing rate became gentle after 2050, reached a relatively stable level after 2080, then gradually reached carbon saturation. Untill 2100, the SOC content of each site reached a relatively higher level by adopting the no-tillage treatment, where the SOC contents of Harbin, Hailun, Nehe, Dehui, Gongzhuling and Lishu were 2.36 g/100 g, 2.81 g/100 g, 2.22 g/100 g, 2.38 g/100 g, 1.97 g/100 g and 2.01 g/100 g, respectively. The SOC contents increased by 52.47% when compared with the initial value, and the simulated average annual increase of SOC for 84 years was 0.0082 g/100 g.

Highlights

Phaeozem is mainly distributed in China’s northeast plain, located in the region of 122–132◦E, 43–50◦N
This paper focused on the effect of different management practices on soil organic carbon (SOC) by considering the simulation of crop yields
We mainly analyzed the effect of simulating SOC by using calibrated parameters through several aspects including scatter diagram, normalized root mean square error (NRMSE), model efficiency (EF), and mean absolute error (MAE)

Summary

Introduction

Phaeozem is mainly distributed in China’s northeast plain, located in the region of 122–132◦E, 43–50◦N. The area of phaeozems is approximately 11 million hectares in the Northeastern Plain, of which 8.15 million hectares is cultivated land. Due to the higher soil organic carbon (SOC) content and appropriate texture, it produced around 40% of total grain production on only 21% of the arable land in the three provinces in the northeast of China [1]. The phaeozem region is one of the most important grain production bases in China. The SOC content is an important indicator of soil quality [2,3]. It had been estimated that the total SOC pools of China in 1 m soil layer and topsoil were 12.6 Pg and 7 Pg, respectively, among which the SOC pool in Northeastern China accounted for one quarter. Many other studies have shown the importance of phaeozem [7,8]

Methods

Results

Conclusion