Effects of surface and subsurface drip irrigation regimes with saline water on yield and water use efficiency of potato in arid conditions of Tunisia
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Fathia El Mokh, Kamel Nagaz, Mohamed Moncef Masmoudi, Netij Ben Mechlia. (24/7/2014). Effects of surface and subsurface drip irrigation regimes with saline water on yield and water use efficiency of potato in arid conditions of Tunisia. Journal of Agriculture and Environment for International Development, 108(2), pp. 227-246.
Abstract
Field experiments were conducted on a sandy soil during spring of 2009
and autumn of 2010 in southern Tunisia for evaluating the effects of two drip
irrigation methods and three irrigation regimes on soil moisture and salinity, yield
and water use efficiency of potato (Solanum tuberosumL.). The surface drip (SDI)
and subsurface drip (SSDI) irrigation methods were used. Irrigation regimes
consisted in replacement of cumulated ETc when readily available water is
depleted with levels of 100 % (FI100), 60 % (DI60) and 30 % (DI30). FI100 was
considered as full irrigation while DI60 and DI30 were considered as deficit
irrigation regimes. Well water with an ECi of 7.0 dS/m was used for irrigation.
Findings are globally consistent between the two experiments. Results show that
soil moisture content and salinity were significantly affected by irrigation
treatments and methods. Higher soil moisture content and lower soil salinity were
maintained with SSDI than SDI for all irrigation treatments. For both irrigation
methods, higher salinity and lower moisture content in the root zone are observed
under DI60 and DI30 treatments compared to FI100. Potato yields were highest
over two cropping periods for the SSDI method although no significant
differences were observed with the SDI. Irrigation regimes resulted in significant
difference in both irrigation methods on yield and its components. Yields were
highest under FI100. Compared to FI100, considerable reductions in potato yields
were observed under DI60 and DI30 deficit treatments resulting from a reduction
in tubers number/m² and average tuber weight and size. Water use efficiency
(WUE) was found to vary significantly among irrigation methods and treatments
and varied between 5.9 and 20.5 kg/m3. WUE of SSDI method had generally
higher values than SDI. The lowest WUE values were observed for the FI100
treatment, while the highest values were obtained under DI30 treatment for both
methods. SSDI method provides significant advantage on yield and WUE and
reduces the soil salinity compared to the SDI in potato production under
experimental conditions. The SSDI and FI100 irrigation techniques seem to optimize the use of saline water in potato production and to control soil salinity.
Under situations of water shortage, adopting deficit irrigation treatment (DI60)
could be an alternative for irrigation scheduling of spring and autumn potato
under the arid conditions of southern Tunisia.