Against the backdrop of the “storing grain in land and technology” strategy and pressing food security challenges, understanding biased technological progress in grain production is crucial. This study constructs a three-factor Constant Elasticity of Substitution (CES) production function—incorporating agricultural machinery, chemical fertilizer, and labor—and employs a normalized supply-side system with Nonlinear Seemingly Unrelated Regression (NLSUR) to analyze biased technological progress across 26 Chinese grain-producing provinces from 2004 to 2023. Total factor productivity (TFP) is also decomposed to assess this progress’s contribution. The results indicate that first, technological progress generally evolves along a “machinery–fertilizer–labor” path. Recently, the primary driver shifted from machinery to fertilizers, aligning with fertilizer reduction and green development policies. Second, TFP growth exhibits phased characteristics, declining during the post-agricultural tax reform period (2005–2013) and rising amid supply-side structural reforms and the “storing grain in technology” strategy (2014–2023). Third, marketization, demand, and digitalization promote fertilizer-oriented progress; specialization drives machinery-oriented progress; and road infrastructure facilitates labor-oriented progress. These results offer empirical evidence for policy evaluation and guidance for optimizing factor allocation, advancing the green transition, and safeguarding food security.
LI et al. (2026) studied this question.