Spear yield and quality of wild asparagus (Asparagus acutifolius L.) as an understory crop in two olive systems

In a dynamic and uncertain global framework, marked by strong fluctuations in the prices of energy and raw materials, and by climate change, investing in long-cycle crops, such as trees, is risky. A diversified agrosystem with multiple income possibilities can be more resilient. Along these lines, it could be advantageous to intercrop olive trees with understory species. Among these, a wild asparagus (Asparagus acutifolius L.) has been suggested as a good candidate. In this study, the wild asparagus spear yield and quality from plants grown along the rows of olive trees were evaluated. Two olive growing systems, a super high density (SHD), and a high density (HD) olive orchard, were considered and compared to an open-field control where the asparagus was grown as a pure stand without olive trees. Over the three years of experimentation, spears were harvested weekly, during harvest time, and immediately separated into edible (tender) and inedible (hard) portion. The two portions were weighed fresh and after drying. Cumulative yield per plant (over the three years) in SHD and in HD was, respectively, 28% and 32% less than in the control. Control spears had a lower percentage of edible portion than SHD and HD, a higher percentage of dry matter on the edible portion, and were thicker. When considering only the edible portion, cumulative yield per plant in SHD and in HD was, respectively, 22% and 26% less than in the control. The cultivation of wild asparagus in the olive orchard could provide additional yield and income on the same unit land area.