Belmokhtar Hena SoheirBenadjila RaniaYAZIT SIDI-MOHAMMED2026-09-152026-09-152026https://dspace.univ-temouchent.edu.dz/handle/123456789/7597Soil fertility is a key factor in ensuring sustainable agricultural production. In this context, the valorization of organic waste represents an environmentally friendly alternative for improving soil properties while reducing the environmental impact of waste. The objective of this study was to evaluate the effect of coffee grounds and potato peels, used as organic amendments, on the physicochemical properties of soil and on the growth of lettuce (Lactuca sativa L.). To achieve this objective, four treatments were established: a control soil (T0), soil amended with coffee grounds (T1), soil amended with potato peels (T2), and soil amended with a mixture of coffee grounds and potato peels (T3). Plant growth parameters (plant height, number of leaves, leaf length, fresh biomass, and dry biomass) as well as selected soil chemical properties (pH, organic matter, and electrical conductivity) were evaluated after composting and after cultivation. The results showed that the organic amendments improved soil properties and promoted lettuce growth. Treatment T2 recorded the best performance, with a final plant height of 16 cm, a leaf length of 15 cm, and the highest fresh (9.53 g) and dry (0.55 g) biomass values. Soil analyses also revealed an increase in organic matter content in the amended treatments, while soil pH remained close to neutrality. An increase in electrical conductivity was observed after cultivation, reflecting the gradual release of mineral nutrients during the decomposition of the organic amendments. These findings highlight the agronomic potential of coffee grounds and potato peels as organic amendments capable of improving soil fertility and enhancing lettuce growth, thereby contributing to more sustainable agricultural practices.frSoil fertilityOrganic amendmentsCoffee groundsPotato peelsLettuce (Lactuca sativa L.)Organic matter.Thesis