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A Stochastic Approach to the Crop Yield‐Irrigation Relationships in Heterogeneous Soils: I. Analysis of the Field Spatial Variability
Author(s) -
Russo David
Publication year - 1986
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1986.03615995005000030036x
Subject(s) - spatial variability , soil water , irrigation , environmental science , soil science , soil salinity , salinity , water content , crop yield , yield (engineering) , hydrology (agriculture) , agronomy , mathematics , statistics , geology , oceanography , geotechnical engineering , materials science , metallurgy , biology
When a deterministic irrigation regime is applied to a heterogeneous field, soil‐water content, soil salinity, and crop yield will vary in space because of the inherent spatial variability in the soil properties. It is important, therefore, to analyze their spatial distributions in the field in order to suggest improved irrigation management schemes for spatially‐variable fields. A stochastic approach was used to analyze the spatial variability of four parameters of the soil‐water retention curve as well as that of the initial soil‐water content and soil salinity, using actual measured field data. These properties were used as inputs for a simplified crop yield‐soil‐water model which, in turn, was coupled with the conditional simulation method to analyze the spatial distribution of the calculated soil‐water content (θ), soil salinity ( C ), and relative crop yield ( Y ) in an irrigated field, for various combinations of irrigation water quantity and quality (salinity). Analysis of the results showed that both irrigation water quantity and quality affected the spatial variability in θ, C , and Y but essentially did not affect the spatial dependence of these properties. Although the average (spatial) response of the field was similar to that of a fictitious equivalent homogeneous field, the response of different sites in the field was quite different. For some combinations of irrigation water amount and salinity, the relative difference between relative crop yield obtained at different sites in the field exceeded 100%.