<p>"Soil Testing and Formulated Fertilization Technology (STFFT)" and "Straw Returning (SR)" are two key agricultural practices currently being implemented in China. However, prior fragmented studies have failed to offer a comprehensive quantitative analysis of integrating these technologies into Chongqing's staple and oilseed cropping systems. This study addresses this gap by conducting 128 site-year field comparative experiments, covering more than 80% of the provincial main production areas. Using Life Cycle Assessment, it quantifies and compares the impacts of conventional farming practices (FP) and the integrated technology model (SFS) on four major crops: rice, maize, tuber crops, and rapeseed, focusing on crop yield, nitrogen footprint (NF), carbon footprint (CF), and net ecosystem economic benefits (NEEB). The results showed that SFS significantly increased the yield of all four crops, with rapeseed showing the highest yield growth rate of 19% compared to FP. Additionally, SFS led to substantial reductions in both NF and CF across all crops, with tuber crops experiencing the most significant environmental cost reduction (25% in NF and 18% in CF). Furthermore, the SFS model notably increased NEEB for all crops, with maize exhibiting the largest improvement (up to 72%). Notably, straw returning in rice systems resulted in increased CH₄ emissions, highlighting the consideration of post-harvest management strategies. For the Chongqing and other similar mountainous regions, the SFS model provides a practical framework for developing low-carbon, profitable, and environmentally sustainable crop production systems.</p>