The role of bentonite and plant residuals in reducing the salinity of well water and improving some properties of sandy soils and the growth and plant of tomato

The laboratory experiment was carried out in the laboratories of the Department of Soil Sciences and Water Resources, College of Agriculture, University of Basra, using a complete randomized block design with two factors, the first factor is the type of filter [three filters of palm kernels mixed with sand at mixing ratios (25%, 50% and 75%) and three filters of bentonite mixed with sand at mixing ratios (25%, 50% and 75%)] and the second factor is the period for passing the salty well water through the filters (1, 24 hours). The chemical properties of the water were estimated after filtration, and the percentage of removal efficiency was calculated to determine the best filters. The results showed that the adoption of the bentonite filter mixed with sand at a mixing ratio of 75% recorded the lowest electrical conductivity when filtration for 24 hours, with reduction rates of 46.50%, 49.20%, and 51.94 % in treating well water. This indicates its high efficiency in reducing water salinity and suggests the possibility of using it to irrigate cultivated tomato plants. In mixed sandy soils and it also gave the lowest concentration of all positive and negative ions in the treated water compared to water treated at other times. An experiment was conducted in the agricultural fields of the College of Agriculture, University of Basra, using a randomized complete block design (RCBD) with three factors. The first factor is the natural mineral and organic amendments (bentonite and palm kernel oil). The second factor is three levels of the mineral amendment (bentonite) (0, 5, 10, M0, M1, M2) megagram ha-1. The third factor is adding three levels of the organic amendment (palm kernel oil) (0, 5, 10, O2, O1, O0) (megagram ha-1) in succession. The results showed that the type and level of addition of amendments used in the study affected the improvement of some chemical properties of sandy soils. The result showed that the best treatment was for the soil treated with bentonite amendment at a level of 10 tons ha-1, reaching 3.02, while the degree of soil reaction increased when the soil was treated with bentonite amendment compared to the palm kernel amendment treatment. As for the fertility properties of the soil, it is noted from the results that the effect of all amendments was positive in these characteristics, as it led to an increase in the available nitrogen, phosphorus, and potassium ions in sandy mixed soils. The amendments took the following order in improving the soil content of ions ready for absorption by the plant: bentonite > palm kernel. The bentonite amendment treatment outperformed the rest of the amendments in the production of dry matter of the vegetative and root systems and the total yield. The treatment of the addition level of 10 tons ha-1 outperformed the rest of the treatments in the production of dry matter of the vegetative and root systems and the total yield.