Optimum Stand Density for Maximum Essential Oil Yield in Commercial Fennel Crops

Abstract

<jats:p>Fennel (<jats:italic>Foeniculum vulgare</jats:italic> Mill.) is grown commercially in Tasmania for the production of a steam-distilled essential oil, which is high in <jats:italic>trans</jats:italic>-anethole. Often, only the generative canopy is harvested since this contains the bulk of the oil and further this oil is higher in anethole than oil from other parts of the plant. Regardless of whether the whole crop is forage harvested or the generative canopy alone is removed using a combine-harvester, the most efficient oil production occurs when the greatest proportion of the canopy is generative, giving maximum oil yield from a minimum of fresh weight to be processed. A trial was conducted to examine the relationship between stand density and the various yield components of fennel in order to predict the likely effect on yield of increasing stem density as the short term perennial crop matures. As for most crops, planting density and biomass yield are closely related and the optimum planting density was predicted using a mathematical model. The results suggest that an initial stand density of 10 to 12 plants/m<jats:sup>2</jats:sup>, in a square layout, would produce the greatest yield of essential oil per unit area by maximising the production of the generative canopy. This density also maximises the yield of oil relative to the weight of material to be distilled.</jats:p>

Rhizobacterial species richness improves sorghum growth and soil nutrient synergism in a nutrient-poor greenhouse soil

“…The plant density is a key determinant of agro- and natural-ecosystems productivity while it influences the quality and quantity of important agro-ecological traits 63 – 65 . Nevertheless, the higher plant density, as we observed in the rhizobacterial treatments, is considered a good indicator of plants agronomic traits and productivity under marginal soil conditions 66 , 67 .…”

Converting simulated total dry matter to fresh marketable yield for field vegetables at a range of nitrogen supply levels

“…Most vegetable crops are grown in rows with set distances between the individual plants, so altering the planting distance within or between the rows can affect the growth of the individual plant considerably (Csizinszky 1996;Falzari et al 2006;Ferrari et al 2008;Jett et al 1995). The main reason for lowering plant density is to increase the supply of nutrients, water and radiation to the individual plants (Francescangeli et al 2006;Hussaini et al 2000).…”

Variation in fatty acid content and composition among Iranian fennel landraces

“…During the growing season, no diseases or pests were observed. After seedling emergence, seedlings were thinned to a final plant density of 10 plants per m 2 for each landrace in each plot (Khorshidi et al, 2010;Falzari et al, 2006;El-Gengaihi and Abdallah, 1978). Wheat was grown in this field the two years before the current study; the wheat residues were incorporated in the soil, and no supplemental fertilizer was applied.…”