Spatial distribution and variability of soil salinity in film-mulched cotton fields under various drip irrigation regimes in southern Xinjiang of China

Soil salt distribution and cotton growth under mulched drip irrigation with soil moisture regulation in southern Xinjiang,China

“…In the vertical direction, the soil moisture and soil salinity both inside and outside the film increased first and then decreased with the increase of soil depth after irrigation, and the distribution of soil water content and soil salt content was similar to oval shape. What's more, the soil salinity inside the film was significantly lower than that outside the mulch in 0-60 cm layer, however, little difference was found in 60-100 cm layer both inside and outside the film, which consistent with the researches (Zhang et al 2013;Ren et al 2021;Hou et al 2022) that soil salt accumulated especially in the surface 0-20 cm soil layer, but not in the deep 60-80 cm soil layer. Besides, the soil water humid perimeter contains the vertical depth and the horizontal distance of soil salt leaching increased with the decrease of soil moisture lower limit, which was in agreement with the study of Hou et al (2022).…”

“…Generally, different from the irrigation strategy triggered by the crop evapotranspiration (ETc) (Hou et al 2021;Hou et al 2022), soil moisture lower limit also used as the indicator for triggering irrigation (Thompson et al 2007;Zotarelli et al 2009;Yan et al 2020), since the available soil water in the rootzone was in the range of field capacity to wilting coefficient (Campbell et al 1982;Hanson et al 2000;Panda et al 2003;Wang et al 2015). Many researches have focused on the appropriate crop irrigation patterns in arid and semi-arid areas with soil water lower limit regulation, such as irrigation schedules with vacuum manometer measuring the soil matrix potential at 20 cm depth directly below the emitter (Li et al 2022;Wang et al 2011;Liu et al 2011b;Li et al 2018;Kochler et al 2007).…”

“…Moreover, the increase of irrigation frequency and decrease of irrigation amount for each application were conductive to preventing the upward of underground water (Mu et al 2011). It is obvious that the greater of the irrigation amount, the deeper of the leaching salt depth and the better of the leaching effect (Wang et al 2012;Hou et al 2022;Xiao et al 2021), however, the inconsistent irrigation amount and irrigation times regulated by soil moisture increases the difficulty for exploring the distribution of soil water and soil salt. (2016) has indicated that the soil water regulation with moderate deficit (50%-60% FC) at each cotton growth stage exhibited significant facilitation effects on the cotton root growth, which could effectively regulate the shoot root ratio.…”

Soil Moisture Regulation under Mulched Drip Irrigation Influences the Soil Salt Distribution and Growth of Cotton in Southern Xinjiang, China

“…Generally, different from the irrigation strategy triggered by crop evapotranspiration (ETc) [ 2 , 7 ], the soil moisture lower limit is also used as the indicator for triggering irrigation [ 8 , 9 ] since the available soil water in the root zone is in the range of field capacity to wilting coefficient [ 10 , 11 , 12 ]. According to the principle of “soil salt moves with water”, soil salinity is easily influenced by irrigation regimes, while soil salt distribution follows the soil water flux pattern [ 13 ].…”

“…Moreover, the increase in irrigation frequency and decrease in irrigation amount for each application were conducive to preventing the upward rise of underground water [ 16 ]. It is obvious that the greater the irrigation amount, the deeper the leaching salt depth and the better the leaching effect [ 7 , 17 , 18 ]; however, the inconsistent irrigation amount and irrigation times regulated by soil moisture increase the difficulty in exploring the distribution of soil water and soil salt.…”