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Submitted to: Perspectives in Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/31/2015 Publication Date: 6/1/2015 Citation: Banuelos, G.S. 2015. Coping with naturally high levels of soil salinity and boron in the westside of central California. Perspectives in Science. 3:4-6. Interpretive Summary: California has one of the most productive agricultural regions of the world, producing more than 400 commodities with a value of more than $37 billion. In the Westside of central California, over 200,000 hectars exhibit naturally high levels of salinity and boron in the soils, especially those derived from Cretaceous soils. Both excessive salt and boron negatively impact agronomic production in this part of California, which has severe economic consequences for the farming communities. Developing new salt and boron management methods and identifying alternative tolerant crops are essential agronomic strategies for this region of California. Researchers at the USDA-ARS have conducted multi-year extensive research trials in these poor quality soils and have identified salt and boron tolerant crops that also have potential economic value. These include mustard, canola, cactus, safflower, sunflower, salt-grass, and poplar trees. Biobased products of economic value from these plants are biodiesel and Selenium-enriched animal feed rations. Producing products of economic value from salt and boron-tolerant crops can contribute to the long-term sustainability that is essential for success and acceptance by growers to utilize poor-quality soils for the production of alternative crops. Technical Abstract: In the Westside of central California, over 200,000 ha exhibit naturally high levels of salinity and boron (B). The Coast Ranges of the west central California evolved from complex folding and faulting of sedimentary and igneous rocks of Mesozoic and Tertiary age. Cretaceous and Tertiary marine sediments dominate the Coast Ranges, which drain to the western San Joaquin Valley. These marine shales and sandstones weathered into a sulfate regime evidenced by extensive salt efflorescenies and evaporites at water and shale surfaces. Weathering of reduced shale (oxidation of pyrite, FeS2) was largely a reversal of the chemistry of the early diageneses of the shale (reduction of sulfate), and contributed to the presence of natural-occurrence of salts, including boron (B) and selenium (Se), in soils, shallow ground waters, and even in drainage waters originating in parts of the westside on the San Joaquin Valley. Both excessive salt and B negatively impact agronomic production in this part of California. Researchers at the USDA-ARS have conducted multi-year extensive research trials in an attempt to identify crops that are both salt and B tolerant and also have potential economic and agronomic value. They determined that the following crops; Brassica spp (mustard, canola), cactus (Opuntia ficus-indica), safflower (Carthamus tinctorius), sunflower (Helianthus annuus), salt-grasses (Distichlis spicata), and poplar trees (Populus deltoides), tolerated soils that had sulfate salinity levels ranging from 6 to 15 dS/m and soluble B and selenium (Se) ranging from 5 to 12 B mg/L and 0.25 mg Se/L, respectively. The selected plant species produced products of economic value, which included biodiesel and Se-enriched animal feed rations. Producing products of economic value from salt and B-tolerant crops can contribute to the long-term sustainability that is essential for success and acceptance by growers to utilize poor-quality soils for the production of alternative crops. |
