SALINITY-L: 199512XX
is the compilation of discussion during Dec 95
via AB4EL Web Digests @ SunSITE
>From root@crcnis1.unl.edu Wed Dec 6 19:37 EST 1995
Date: Mon, 04 Dec 1995 19:09:31 -0600
Message-Id: <199511190109.AA05504@crcnis1.unl.edu>
Subject: SALINITY-L digest 22
Contents:
SALINITY-L digest 22 NOT RECEIVED
Date: Mon, 04 Dec 1995 18:09:31 -0600
From: AB4EL <modena@SunSITE.unc.edu>
Subject: SALINITY-L digest 22 NOT RECEIVED
SALINITY-L digest 22 NOT RECEIVED
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>From root@crcnis1.unl.edu Wed Dec 13 19:37 EST 1995
Date: Mon, 11 Dec 1995 19:09:31 -0600
Message-Id: <199511190109.AA05504@crcnis1.unl.edu>
Subject: SALINITY-L digest 23
Contents:
SALINITY-L digest 23 NOT RECEIVED
Date: Mon, 11 Dec 1995 18:09:31 -0600
From: AB4EL <modena@SunSITE.unc.edu>
Subject: SALINITY-L digest 23 NOT RECEIVED
SALINITY-L digest 23 NOT RECEIVED
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>From root@crcnis1.unl.edu Wed Dec 20 19:37 EST 1995
Date: Mon, 18 Dec 1995 19:09:31 -0600
Message-Id: <199512190109.AA05504@crcnis1.unl.edu>
Subject: SALINITY-L digest 24
Contents:
Atriplex salt content (Mike Schulz <SCHULZM@salty.agvic.gov.au>)
Date: Tue, 19 Dec 1995 10:28:10 +0000
From: Mike Schulz <SCHULZM@salty.agvic.gov.au>
Subject: Atriplex salt content
At ISIA-Tatura we have been looking at means of overcoming the high
salt content, mainly Na & Cl, in Atripex leaves. Being halophytes
their is always going to be a substantial amount of salt but the
level can be reduced by harvest management, profile leaching,
breeding (?), species (?).
Harvest management - graze to consume young leaves or, after periods
of low profile salinity.
Profile Leaching - reduces average leaf salt content only if leaching
dramatically reduces the profile salinity and only if it continues
long enough for young, low salt leaves to accumulate and old, high
salt leaves to senesce. There is a severe danger of aggregate
dispersion with this approach.
Breeding - In our work with A. cinerea the leaf salt content is at
least partially determined genetically. Some potential for breeding
may exist here but possibly at the expense of salt tolerance.
Species - This is the main reason for this correspondence. I've
recently analysed leaf material from 8 Atriplex species grown on a
saline, gypsiferous site. A. canescens has an extremely low [Na]
(0.22% of dry matter) for an Atriplex, while six of the other species
had the more common level of 5.1 - 7.5%. This pattern was also
reflected in the [Cl] but with only a 3 to 4 fold difference.
Another striking difference was the Na/K ratio. A. canescens had a
ration of >20 while the others were aprrox. 0.5. The other species
were amnicola, cinerea, lentiformis, nummularia, semibaccata,
undulata & vesicaria.
Has anyone any experience with A. canescens relative feed quality ?
Schulzzzzzzz............
Inst. of Sustainable Irrigated Agriculture - Tatura
Agriculture Victoria
Department of Agriculture Energy and Minerals
Government of Victoria
Australia
End of Digest
>From root@crcnis1.unl.edu Wed Dec 20 19:55 EST 1995
Date: Wed, 20 Dec 1995 07:25:56 -0600
Message-Id: <199512201325.AA29734@crcnis1.unl.edu>
Subject: SALINITY-L digest 25
Contents:
New Subscriber (jhm@maties.sun.ac.za)
Date: Wed, 20 Dec 95 14:53 +0200
From: jhm@maties.sun.ac.za
Subject: New Subscriber
Dear colleagues
I am a new subscriber to SALINITY-L and would like to introduce myself using
the headings sugested by the List-owner:
I am J. Hulme Moolman, Professor and Head of the Department of Soil- and
Agricultural Water Science, Faculty of Agricultural Sciences, University of
Stellenbosch, Stellenbosch, SOUTH AFRICA. The town is situated in the
south-western part of South Africa, about 50km north-east of the city of Cape
Town.
My interesest in salinity stems mainly from the fact that South Africa is a
semi-arid country with a mean annual rainfall of ca. 480mm/a. The
south-western part of the country, where I live, has a Mediterranean climate
with a wet winter of about 4 months followed by a long hot and dry summer.
In addition to the low rainfall and high rate of evaporation (>2000mm/a), the
geology of this part of the country is such that the parent material of the
soils in the valley-bottom areas are shale, i.e. of marine origin. As a
consequence, the soils (in areas where the rainfall is <300mm/a) as a rule
are eutrophic, bordering on saline. The salt content of the three
principle rivers in the south-western part of the country, furthermore
increase downstream from the head-waters, as well as in time. Competion
between industry (and urban areas) and agriculture for good quality
water increases, and agriculture in future will not only have to affect
substantial savings on water, but also will have to irrigate with water of a
lower quality than is presently the case. This is of prime concern to the
wine- and fruit farmers of the Western Cape.
I have been doing research on salinity and related problems (including
modelling of water and solute transport in soils) for the last 20 years.
Since 1990 I have been busy with a long term research project on the salt
tolerance of grapevine. A mature Colombard grape vineyard, on 99 Richter
root stock, is irrigated with six levels of saline water ranging in salt
content from 25-35 mS/m (the control treatment) to 500mS/m. Based on the
results of the first four seasons, we have concluded that grapevines are
considerably more sensitive to salinity than previously reported by Maas &
Hoffman (1977) and Ayers & Westcott (1985). Also, we have not been able to
determine a threshold salinity value. The minimum ECe achieved is 75mS/m. Any
increase in salinity beyond this minimum value, results in a progressive
yield decrease. The final report of this experiment should be released by our
Water Research Commission towards the end of 1996. The initial results of
this project were presented at the Fifth International Microirrigation
Congress in Florida, USA, in April 1995.
Two years ago, we started with asimilar experiment in a higher rainfall area
(>700mm/a) but wth Weisser-Riesling as the cultivar. One of my students is
also looking at the salt tolerance of apricots (this is a lysimeter study).
Two of my main problems thus far are:
1) Practical ways of scheduling irrigation applications in a saline
environment, and
2) How to calculate the water balance of micro-irrigated vineyards and
orchards where only part of the soil surface and soil volume is
wetted. My research to date shows that this problem has a large effect on
the estimate of soil-based calculations of crop evapotranspiration.
Looking forward to get an international response.
Prof. J. Hulme Moolman
Voorsitter Chairman
Dept. Grond- en Landbouwaterkunde Dept. Soil and Agricultural Water Science
Universiteit Stellenbosch University of Stellenbosch
Stellenbosch 7600 Stellenbosch 7600
SUID-AFRIKA SOUTH AFRICA
Tel: 021-8084790 (National) 27-21-8084790 (International)
Fax: 021-8084336 (National) 27-21-8084336 (International)
EMAIL: JHM@MATIES.SUN.AC.ZA
End of Digest
Prepared by Steve Modena, AB4EL
Suggestions and comments to: modena@SunSITE.unc.edu