Smallholder farming systems in Tanzania are characterized by high variability in productivity and efficiency. A longitudinal study employing a difference-in-differences approach to assess changes in farm performance across different regions and farming practices. Farmers who adopted improved crop varieties saw an average increase of 15% in yield, with a standard deviation of 3%, indicating significant efficiency gains over two years. The quasi-experimental design provides robust evidence for the effectiveness of technology adoption in enhancing smallholder farm productivity and sustainability. Policy makers should prioritise supporting farmers with access to improved seeds and training programmes, thereby fostering long-term agricultural development. The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.