The impact of different soils and wastewater on castor bean (Ricinus communis L.) growth

The oilseed plant castor bean (Ricinuscommunis L.) has many applications in medicine, industry and agriculture. This study aims to evaluate the growth of castor bean on different soils as affected by wastewater (sewage effluent) irrigation. Thus, castor bean seeds were sown in six different soils (sandy soil - sandy soil + compost - polluted soil - clay soil - calcareous soil - saline soil) and irrigated using equal amounts of sewage effluent. The physical and chemical properties of the soils used and the chemical constituents of sewage effluent were investigated. The results showed that the highest percentage of germination of castor bean seeds (96.6%) were achieved in the clay as well as sandy soil with added compost, followed by sandy soil (92.2%). On the other hand the lowest germination percentages were shown with the seeds sown in calcareous soil (50.3%) and saline soil (30.3%). The time duration required for the radical protrusion was also shortest (quick germination) and longest in the polluted, calcareous, and saline soils. There has been also a marked impact on the plant growth, fresh weight and dry weight gain of, where highest values were shown with the plants cultivated in clay soils followed by sandy soil with added compost. These plants exhibited in addition best criteria (weight, length, width). Thus, the results obtained confirmed the ability of castor beanto grow in different types of soils under irrigation by sewage effluent.