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Coping with salinity in irrigated agriculture: crop evapotranspiration and water management issues
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Orientador(es)
Resumo(s)
Soil and water salinity and associated problems are a major challenge for global food production. Strategies to
cope with salinity include a better understanding of the impacts of temporal and spatial dynamics of salinity on
soil water balances vis-à-vis evapotranspiration (ET) and devising optimal irrigation schedules and efficient
methods. Both steady state and transient models are now available for predicting salinity effects on reduction of
crop growth and means for its optimization. This paper presents a brief review on the different approaches
available, focusing on the FAO56 framework for coping with the effects of soil salinity on crop ET and yields. The
FAO56 approach, applied widely in soil water balance models, is commonly used to compute water requirements,
including leaching needs. It adopts a daily stress coefficient (Ks) representing both water and salt stresses
to adjust the crop coefficient (Kc) when it is multiplied by the grass reference ETo to obtain the actual crop ET
values for saline environments (ETc act=Ks Kc ETo). The same concept is also applied to the dual Kc approach,
with Ks used to adjust the basal crop coefficient (Kcb). A review on applications of Ks is presented showing that
the FAO56 approach may play an interesting role in water balance computations aimed at supporting irrigation
scheduling. Transient state models, through alternative formulations, provide additional solutions for quantification
of the salinity build-up in the root zone. These include irrigation-induced salinity, upward movement of
salts from saline ground water-table, and sodification processes. Regardless of the approach, these models are
now very much capable of supporting irrigation water management in saline stress conditions. For maintaining
crop growth under salinity environments, soil-crop-water management interventions consistent with site-specific
conditions are then discussed. Adequateness of irrigation methods, cyclic uses of multi-salinity waters and
proper irrigation scheduling are further analyzed as examples of efficient means to obviate the effects of salinity
Descrição
Review
Palavras-chave
FAO56 correcting Kc for salinity leaching requirement salinity modeling salinity management irrigation to cope with salinity water and salinity stress coefficient (Ks)
Contexto Educativo
Citação
Agricultural Water Management 227 (2020) 105832
Editora
Elsevier