Evaluating net primary productivity dynamics and their response to land-use change in the loess plateau after the 'Grain for Green' program

Ruichen Mao; Lutong Xing; Qiong Wu; Jinxi Song; Qi Li; Yongqing Long; Yuna Shi; Peng Huang; Qifang Zhang

doi:10.1016/j.jenvman.2024.121112

Evaluating net primary productivity dynamics and their response to land-use change in the loess plateau after the 'Grain for Green' program

J Environ Manage. 2024 May 10:360:121112. doi: 10.1016/j.jenvman.2024.121112. Online ahead of print.

Authors

Ruichen Mao¹, Lutong Xing¹, Qiong Wu¹, Jinxi Song², Qi Li¹, Yongqing Long¹, Yuna Shi¹, Peng Huang¹, Qifang Zhang¹

Affiliations

¹ Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China.
² Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China; Institute of Qinling Mountains, Northwest University, Xi'an, 710127, China. Electronic address: jinxisong@nwu.edu.cn.

PMID: 38733847
DOI: 10.1016/j.jenvman.2024.121112

Abstract

Assessing net primary productivity (NPP) dynamics and the contribution of land-use change (LUC) to NPP can help guide scientific policy to better restore and control the ecological environment. Since 1999, the "Green for Grain" Program (GGP) has strongly affected the spatial and temporal pattern of NPP on the Loess Plateau (LP); however, the multifaceted impact of phased vegetation engineering measures on NPP dynamics remains unclear. In this study, the Carnegie-Ames-Stanford Approach (CASA) model was used to simulate NPP dynamics and quantify the relative contributions of LUC and climate change (CC) to NPP under two different scenarios. The results showed that the average NPP on the LP increased from 240.7 gC·m^-2 to 422.5 gC·m^-2 from 2001 to 2020, with 67.43% of the areas showing a significant increasing trend. LUC was the main contributor to NPP increases during the study period, and precipitation was the most important climatic factor affecting NPP dynamics. The cumulative amount of NPP change caused by LUC (ΔNPP_LUC) showed a fluctuating growth trend (from 46.23 gC·m^-2 to 127.25 gC·m^-2), with a higher growth rate in period ΙΙ (2010-2020) than in period Ι (2001-2010), which may be related to the accumulation of vegetation biomass and the delayed effect of the GGP on NPP. The contribution rate of LUC to increased NPP in periods Ι and ΙΙ was 101.2% and 51.2%, respectively. Regarding the transformation mode, the transformation of grassland to forest had the greatest influence on ΔNPP_LUC. Regarding land-use type, the increased efficiency of NPP was improved in cropland, grassland, and forest. This study provides a scientific basis for the scientific management and development of vegetation engineering measures and regional sustainable development.

Keywords: CASA model; Land use change; Loess plateau; Net primary productivity; Scenario simulation.