Impact of China’s Agricultural Water Policy Reforms on Water Usage Efficiency and Total Factor Productivity Change

The Chinese government implemented policy reforms in the agricultural sector in 2012 to enhance the efficient utilization of limited agricultural water resources. This study utilized the SBM-DEA (Data Envelopment Analysis with Slack-Based Measure) and Malmquist productivity index to evaluate the Agricultural Water Usage Efficiency (AWUE) and total factor productivity growth across 31 Chinese provinces from 2000 to 2020. Additionally, Meta-frontier analysis was applied to estimate regional agricultural technological heterogeneity. The findings indicate an average AWUE score of 0.7032, suggesting a potential growth of 29.68%. Before the policy reforms (2000–2012) were implemented, the average AWUE score was 0.6743, which increased to 0.7502 after the policy reforms were introduced. The average Malmquist Productivity Index (MI) score for the entire period was 1.0749, representing an average growth in productivity of 7.49%. Technological change (TC) was the primary driver of this productivity growth, with an average TC value of 1.0655, surpassing the Efficiency Change (EC) value of 1.0101. However, there was a decline of 5.03% in MI after the policy implementation. The Technology Gap Ratio (TGR) value for the Sichuan Basin and surrounding regions was notably higher at 0.983, indicating a superior production technology in China's agriculture sector compared to other regions. The Mann–Whitney U and Kruskal Wallis test evaluate the significant statistical differences concerning AWUE, MI, and TGR among regions and periods.