Saltgrass, a True Halophytic Plant Species for Sustainable Agriculture in Desert Regions

Abstract

 Mohammad
Pessarakli Professor. School of Plant
Sciences, the University of Arizona Tucson, AZ 85721, USA * Corresponding
author E-mail:pessarak@ag.arizona.edu   Received: 4 April
2013  Accepted: 12
November 2013       Abstract   Continuous desertification of arable lands due to
urbanization, global warming, and shortage of water mandates use of low
quality/saline water for irrigation, especially in the regions experiencing
water shortage. Using low quality/saline water for irrigation imposes more
stress on plants which are already under stress in these regions characterized
with saline soils and shortage of water. Thus, there is an urgent need for
finding salt/drought tolerant plant
species to survive/sustain under such stressful conditions. Since the native
plants are already growing under such conditions and are adapted to these
stresses, they are the best and the most suitable candidates to be manipulated
for use under these stressful conditions. If stress tolerant species/genotypes
of these native plants are successfully identified, there would be a
substantial savings in cultural practices and inputs in using them by the growers
and will result in substantial savings in the currencies of the countries. My
investigations at the University of Arizona on saltgrass (Distichlis spicata L.), a euhalophytic plant species, have
indicated that this plant has an excellent drought and salinity tolerance with
a great potential to be used under harsh and stressful environmental
conditions. This grass has multi usages, including animal feed, soil
conservation, saline soils reclamation, and combating desertification processes. The objectives of this study were to find the most
salt tolerant of various saltgrass genotypes for use in arid and semi-arid
regions for sustainable agriculture and biologically reclaiming saline soils.
Twelve saltgrass clones were
studied in a greenhouse, using the hydroponics technique to evaluate their
growth responses in terms of shoot and root lengths and DM weights, and general
grass quality under salt stress conditions. Grasses were grown vegetatively in Hoagland solution for 90 days prior to
exposure to salt stress. Then, 4 treatments [EC of 6 (control), 20, 34,
and 48 dSm-1 salinity stress] were replicated 3 times in a RCB design experiment. Grasses were grown
under these conditions for 10 weeks. During this period, shoots were clipped
bi-weekly, clippings were oven dried at 65o C and DM weights were
recorded, and shoot and root lengths were also measured. At the last
harvest, roots were also harvested, oven dried, and DM weights were determined.
General grass quality was weekly evaluated and recorded. Although, all the
grasses showed a high level of salinity tolerance, there was a linear reduction in their growth responses
as salinity level increased. However, there was a wide range of variations
observed in salt tolerance of these saltgrass clones. The superior stress tolerant genotypes were
identified which could be recommended for sustainable production under arid
regions and combating desertification. This grass proved to not only have a
satisfactory growth under the harsh desert conditions, but also to substantially
reduce salinity level of the rhizosphere, which indicates that saltgrass can
effectively be used for biological salinity control or reclamation of desert
saline soils and combating desertification processes.   

Keywords