What is in this article?:
- California soil toxins worsened by drought
- Salt tolerance
- Lack of water will take away one of the weapons California growers can use to combat soil toxins.
Salinity and scarcity of water were very much in the spotlight at the 2014 California Plant and Soil Conference in Fresno.
Multiple speakers showed pictures of what they labeled “California snow,” salt that had precipitated out atop soil where trees and other crops fight to grow.
They painted a grim picture of a year in which sparse winter rains have done little to drive toxic minerals deeper, away from plant roots. They said an expected lack of available water will take away one of the weapons growers can use to combat the toxins.
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But they also talked of water management and steps growers are taking to find salt-tolerant crops or varieties and research on just how “tough” some crops can be.
Among those looking for crops that can survive the less than friendly soils on the Central Valley’s west side is Gary Banuelos, a researcher with the Agricultural Research Service in Parlier.
Banuelos said the villain is not simply limited to salts. Also included as potentially toxic are selenium and boron. He talked of alternate crops for high salt and boron conditions.
Leaching in tiled fields has been one way of coping with the toxins, he said. But leaching boron out of the root ball requires three times the amount of water than that required to leach salt.
“It can be done with water, but it’s almost non-existent (this year),” Banuelos said. “That’s why a lot of land is fallow.”
Banuelos has been looking for plants that can grow in toxic soils, including some varieties of poplars for biomass to generate electricity, cacti with fruit that can be used in juice and other products, grasses that may be blended into cattle feed, mustard, broccoli, safflower and other plants.
“We’re always looking to at least being able to earn between $1,000 and $1,500 an acre or otherwise the crop will not even be considered,” he said.
Others who addressed the conference included:
• Rick Snyder, with UC Davis Cooperative Extension, who had some advice on evapotranspiration-based scheduling during a drought.
He said producers need to take into account fog, morning dew, solar radiation or light interception by the foliage and other factors.
Applying less water will reduce deep percolation, he said, but it could result in higher salinity with the rooting zone so that eventually, deficit irrigation will become more problematic, especially if practiced over a long term drought.
He said producers may want to sort out a percentage of irrigation availability that will still bring profit, idling some land if necessary to assure they have a percentage they can apply to achieve that goal.
In some cases, he said, it might be better to reduce the area planted and apply more water to smaller cropped area to maintain higher production.
If water supplies are inadequate, Snyder said, it is best to irrigate orchards and vines at about the same frequency as in non-drought years, but apply less water per irrigation.