Exploiting dynamic changes in internal screenhouse climate to inform irrigation in bananas

摘要

In Israel's inner valleys banana irrigation under 10 and 20% screens is reduced below rates for open stands by about 25% while in coastal regions reductions are about 10%. The ratio of evaporation inside to that outside decreases during the season mostly due to changes in internal climate caused by accumulation of dust on the screen which reduces transmission of solar radiation and atmospheric evaporative demand. In addition, wind speed is reduced as the banana plants grow and fill the void below thescreens. We are exploiting these changes to inform irrigation management by monitoring climate under the screens and computing reference evapotranspiration (ET0) daily. 'Dynamic' irrigation is set to ET0 of the previous day. The experiment focuses on 3plots: unscreened, 10% 'Crystal Leno' and 20% 'Pearl' screens. Treatments include regional recommendations based on tables developed from previous experiments and average ET0 (one table for each plot), and 'dynamic' irrigation described above. Significant reductions in irrigation have been obtained and after the first 3 years (and the first full fruit season) yield was not significantly reduced. At the end of the dry season a non-significant trend of increased salinity for the reduced irrigation was observed. No other detrimental results were found. Dust accumulation reduced solar radiation transmission by an additional 10% at the end of the dry season in 2016 and 2017. In 2018 a late rain in June cleaned the screens and the radiation reduction was less. While for unscreened plots irrigation averaged 2330 mm year1 for the two years of fully grown plants (2017 and 2018), below the 10 and 20% screen rates were 1814 and 1724 for non-dynamic and 1570 mm and 1368 for dynamic irrigation, respectively. Measurements included sap flow, leaf temperatures, soil salinity, leaf mineral content and horticultural data.