Effects of irrigation water salinity on evapotranspiration modified by leaching fractions in hot pepper plants

We investigated whether leaching fraction (LF) is able to modify the effects of irrigation water salinity (EC(iw)) on evapotranspiration (ET). We conducted an experiment with a completely randomized block design using five levels of EC(iw) and two LFs. Results showed that the electrical conductivity of drainage water (EC(dw)) in an LF of 0.29 was considerably higher during the 21–36 days after transplanting (DAT), and considerably lower after 50 DAT than in an LF of 0.17. The hourly, nighttime, daily, cumulative and seasonal ET all decreased considerably as a result of an increase in the EC(iw). The daily ET started to be considerably higher in the LF of 0.29 than in the LF of 0.17 from 65 DAT. Compared with the LF of 0.17, the seasonal ET in the LF of 0.29 under various EC(iw) levels increased by 4.8%–8.7%. The Maas and Hoffman and van Genuchten and Hoffman models both corresponded well with the measured relative seasonal ET and the LF had no marked effects on these model parameters. Collectively, an increase in the level of EC(iw) always decreased the ET substantially. An increase in the LF increased the ET considerably, but there was a time lag.