Effect of treatment with potassium polyacrylate, biochar, and organic fertilizer on the physiological characteristics of Eruca sativa grown in sandy soil: The study aimed to evaluate the effect of poultry manure, potassium polyacrylate, and biochar on improving the physical and chemical properties of the experimental soil, as well as to investigate the individual and combined effects of these amendments on certain physiological and chemical characteristics of rocket plant (Eruca sativa L.) grown in sandy soil during the autumn season of 2024 in Al-Muqdadiyah District, Diyala Province. The experiment was conducted according to a Randomized Complete Block Design (RCBD) with three factors, including organic fertilizer at two levels (0 and 10 t ha⁻¹), potassium polyacrylate at three concentrations (0, 50, and 100 kg ha⁻¹), and biochar at three concentrations (0, 10, and 20 t ha⁻¹) The results showed significant improvements in the physical and chemical properties of the soil. Soil pH increased from 7.39 to 7.53, electrical conductivity (EC) from 2.30 to 2.57 dS m⁻¹, field capacity (FC) from 8.00 to 13.93%, and organic matter (OM) from 1.18 to 1.46 g kg⁻¹ soil. In addition, soil nitrogen content increased from 66.57 to 74.53 mg kg⁻¹ soil, phosphorus from 10.27 to 11.64 mg kg⁻¹ soil, and potassium from 180.60 to 188.95 mg kg⁻¹ soil. The individual effect of organic fertilizer at 10 t ha⁻¹ significantly increased the relative water content of leaves to 94.08%, while leaf nitrogen, phosphorus, and potassium contents reached 0.991, 0.125, and 1.236%, respectively, compared with the control treatment, which recorded 82.26, 0.686, 0.089, and 0.875%, respectively. Likewise, potassium polyacrylate at 100 kg ha⁻¹ produced the highest mean values of relative water content (109.1%) and leaf nitrogen, phosphorus, and potassium contents of 1.143, 0.141, and 1.368%, respectively, compared with the control treatment. Similarly, biochar at 20 t ha⁻¹ achieved the highest mean values of relative water content (100.9%) and leaf nitrogen, phosphorus, and potassium contents of 0.977, 0.123, and 1.245%, respectively, compared with the control treatment. The triple interaction among organic fertilizer at 10 t ha⁻¹, potassium polyacrylate at 100 kg ha⁻¹, and biochar at 20 t ha⁻¹ recorded the highest mean relative water content of leaves (141.8%) compared with 60.00% in the control treatment. The same treatment also achieved the highest leaf contents of nitrogen, phosphorus, and potassium, reaching 1.537, 0.175, and 1.660%, respectively, compared with the control treatment, which recorded 0.505, 0.052, and 0.355%, respectively. The results indicate that the integration of organic fertilizer, biochar, and potassium polyacrylate effectively contributed to improving the fertility of sandy soil and enhancing plant water status and nutrient uptake, which was positively reflected in the physiological and nutritional performance of rocket plants under sustainable agricultural systems.The study aimed to evaluate the effect of poultry manure, potassium polyacrylate, and biochar on improving the physical and chemical properties of the experimental soil, as well as to investigate the individual and combined effects of these amendments on certain physiological and chemical characteristics of rocket plant (Eruca sativa L.) grown in sandy soil during the autumn season of 2024 in Al-Muqdadiyah District, Diyala Province. The experiment was conducted according to a Randomized Complete Block Design (RCBD) with three factors, including organic fertilizer at two levels (0 and 10 t ha⁻¹), potassium polyacrylate at three concentrations (0, 50, and 100 kg ha⁻¹), and biochar at three concentrations (0, 10, and 20 t ha⁻¹) The results showed significant improvements in the physical and chemical properties of the soil. Soil pH increased from 7.39 to 7.53, electrical conductivity (EC) from 2.30 to 2.57 dS m⁻¹, field capacity (FC) from 8.00 to 13.93%, and organic matter (OM) from 1.18 to 1.46 g kg⁻¹ soil. In addition, soil nitrogen content increased from 66.57 to 74.53 mg kg⁻¹ soil, phosphorus from 10.27 to 11.64 mg kg⁻¹ soil, and potassium from 180.60 to 188.95 mg kg⁻¹ soil. The individual effect of organic fertilizer at 10 t ha⁻¹ significantly increased the relative water content of leaves to 94.08%, while leaf nitrogen, phosphorus, and potassium contents reached 0.991, 0.125, and 1.236%, respectively, compared with the control treatment, which recorded 82.26, 0.686, 0.089, and 0.875%, respectively. Likewise, potassium polyacrylate at 100 kg ha⁻¹ produced the highest mean values of relative water content (109.1%) and leaf nitrogen, phosphorus, and potassium contents of 1.143, 0.141, and 1.368%, respectively, compared with the control treatment. Similarly, biochar at 20 t ha⁻¹ achieved the highest mean values of relative water content (100.9%) and leaf nitrogen, phosphorus, and potassium contents of 0.977, 0.123, and 1.245%, respectively, compared with the control treatment. The triple interaction among organic fertilizer at 10 t ha⁻¹, potassium polyacrylate at 100 kg ha⁻¹, and biochar at 20 t ha⁻¹ recorded the highest mean relative water content of leaves (141.8%) compared with 60.00% in the control treatment. The same treatment also achieved the highest leaf contents of nitrogen, phosphorus, and potassium, reaching 1.537, 0.175, and 1.660%, respectively, compared with the control treatment, which recorded 0.505, 0.052, and 0.355%, respectively. The results indicate that the integration of organic fertilizer, biochar, and potassium polyacrylate effectively contributed to improving the fertility of sandy soil and enhancing plant water status and nutrient uptake, which was positively reflected in the physiological and nutritional performance of rocket plants under sustainable agricultural systems. Euphrates journal of agricultural science, [S. l.], v. 18, n. 2, 2026. Disponível em: https://ejs-agri.com/index.php/EJAS/article/view/727. Acesso em: 12 nov. 2026.