Satellite-Based Detection of Salinity and Sodicity Impacts on Wheat Production in the Mexicali Valley
- Christopher Seiferta,
- J. Ivan Ortiz-Monasteriob and
- David B. Lobell *a
Sodicity and salinity are known constraints on wheat (Triticum aestivum L.) yields in many agricultural areas, especially for irrigated wheat. Objective estimates of the effects of these soil properties across broad scales are often difficult due to the effects of climate, management regimes, and diseases. This study used a satellite-derived, 9-yr yield data set combined with a data set of 8561 soil samples to estimate the effects of sodicity and salinity on wheat yield and the area under production in northwestern Mexico's Mexicali Valley. The results for salinity showed some yield reductions but were largely inconclusive. Sodicity, however, appears to account for an average loss of 1.2% of wheat production each year by harming fields sown to wheat, with negative yield effects seen on at least 32% of land in the data set. We estimate that an additional 1.2% of wheat production in the valley is forgone by farmers avoiding sowing on sodic soils. Yields appear to be negatively affected at an exchangeable Na percentage (ESP) of 6, much lower than the commonly accepted threshold of 15. The results of this study indicate that sodic fields tend to be planted less often and have lower wheat yields in the Mexicali Valley. Total production impacts are on the order of a few percentage points, which is small relative to the total gap between average and maximum on-farm yields.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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