Effect of Olive Pomace Compost Application on the Growth and Yield of Fava Bean Plant

Abstract

Olive cultivation in Morocco has experienced significant growth in recent years, thanks to investments in research and development of olive varieties adapted to local conditions, as well as better management of water and soil resources. However, many challenges remain, including the development of more sustainable farming techniques and the promotion of organic olive farming, as well as the management of waste generated during the crushing process. Indeed, with the pressure system, the processing of one ton of olives generates on average 450 liters of olive mill wastewater and 330 kg of pomace, with a moisture content between 25 and 30%, resulting in an annual production of approximately 50,000 tonnes. The objective of this study is to test the effectiveness of olive pomace compost, derived from the traditional system, as a soil amendment for fava bean cultivation. The germination trials were conducted on an outdoor area of 225 m2 (15*15). The area was divided into six plots, each of which was sown with fava bean seeds (at a rate of 10 seeds/1.5 m2). Each plot contained different doses of olive pomace compost (0% (control), 5%, 10%, 15%, 20%, and 25%). After sowing the fava bean seeds, the plots were irrigated with well water on the day of sowing. The results showed that all the seeds sown in the different percentages of compost presented a significantly different number of leaves, leaf area, and stem size compared to the control plants. At the end of the growing season, the plants fertilized with compost showed significantly larger and more numerous pods compared to the control plants. Similarly, the nutritional quality of the fava beans contained in the pods was significantly higher in terms of protein (8.06 g/100 g), lipids (1.2 g/100 g), total sugars (9.35 g/100 g), and fiber (4.56 g/100 g) compared to the nutritional value of the control plants (protein (5.1 g/100 g), lipids (0.8 g/100 g), total sugars (6.1 g/100 g), fiber (3.1 g/100 g)), especially for the plants fertilized with 10% compost.