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Soil scientist Florence Cassel Sharma gets help
from student research technicians Casey Arnold, left, and Prasad
Yadavali, standing, in setting up irrigation system. |
California State University,
Fresno’s Center for Irrigation Technology (CIT) is researching
alternatives to help cotton farmers on the San Joaquin Valley’s West
Side find other higher-value crops to revitalize returns.
Alternative crops such as tomatoes or melons are not nearly as
comfortable as cotton in West Side soils due to the buildup of salt,
selenium, boron and other chemicals that has made the soil nearly
inhospitable to salt-sensitive field and row crops.
To help reclaim some of the acreage for vegetable crops, a CIT research
team is exploring new methods for changing the chemical properties of
the soil through subsurface drip irrigation.
“Transitioning from cotton to vegetable production and from flood to
drip irrigation presents some new challenges,” said CIT soil scientist
Dr. Florence Cassel Sharmasakar, who is leading the research effort with
Dr. David Gooraho, an assistant plant science professor. “Vegetable
crops are more sensitive to salinity and more susceptible to disease and
deficiency when grown under saline-sodic soil conditions.”
Processing tomatoes are affected by soil salinity and calcium
deficiency, she noted.
According to Cassel Sharma, reclamation of saline-sodic soils has
traditionally involved application of soil amendments high in calcium to
increase available calcium to plants, or applying greater amounts of
water in order to leach the salts down below the root zone. This has
been done through surface systems such as flood and furrow irrigation.
With increasing restrictions on water use on the West Side, however,
growers are being forced to try new methods which have the potential for
greater water-use efficiency.
“The challenge is how to address the reclamation of saline-sodic soils
in the root zone by utilizing subsurface drip tape as the avenue for
application,” Goorahoo said.
Little research has been conducted on soil amendments through subsurface
drip systems, the researchers noted, but potential benefits are
significant, even more so with added potential of water savings.
The research team is examining two specific reclamation alternatives
that could create an improved environment around the drip tape:
Both treatments attempt to
alter soil chemical properties to make the proper nutrients more
available to the crops.
This research will provide important information on the effects –
positive or negative – of each reclamation method on tomato yield,
blossom-end rot, soil calcium availability, plant calcium uptake, and
infiltration rate. The researchers hope to increase processing tomato
yields significantly with effective soil amendment, Cassel Sharma said.
The project is in its first season this summer, with results are
expected next year. For details, contact Cassel Sharma at
fcasselss@csufresno.edu or
Goorahoo at
dgooraho@csufresno.edu.
(Copy by Steve Olson,
publications editor of the California Agricultural Technology Institute
at Fresno State.)
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