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July 2008
Welcome to the July edition of Fertile Minds, the monthly newsletter of Sydney Environmental & Soil Laboratory.
Winter is here, so now is the time to send off your samples for analysis. Very little will change between now and spring, so while things here at the lab have slowed down and before your work load picks up again, use the opportunity to prepare for the next growing season.
If you any questions you would like answered in Fertile Minds, please write to info@sesl.com.au. Or if you have any special requirements, we would be pleased to talk with you and tailor a package and price. Please contact the office on (02) 9980 6554 or write to us at info@sesl.com.au.
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In this issue
- The Loam Ranger – Why perform a grape petiole analysis?
- Winter soil testing for turf
- New versus established turf
- Salinity
- Nitrogen behaviour in the environment
- Did you know ... ? – Saffron
price list
If you would like a copy of our revised price list (some prices have gone down!), please click here.
As usual, if you have any special testing or consultancy requirements, we would be pleased to discuss them with you and tailor a package and price accordingly. Please contact the office on (02) 9980 6554 or info@sesl.com.au with your request.
Reader feedback
Prompted by our article on coconut in the last issue, Sam Cowie, of Leaf & Limb Horticultural Consultancy, has drawn our attention to a development in coconut processing that put control of coconut oil production back into the hands of the small-scale producers: Kokonut Pacific makes and distributes a low-tech coconut oil presser, supporting Fair Trade throughout the Pacific and Indonesia.
The Loam Ranger – Why perform a grape petiole analysis?
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Dear Loam Ranger, I’m a grape grower. One of my neighbours says I should get my soil tested, but the other says I should get the grape leaves tested. Who’s right? Whether tissue or soil testing is more useful in grapevine management is always the subject of argument. But these arguments can miss the point: that soil testing and petiole testing are used for different management purposes. |
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Winter soil testing for turf
Winter is an ideal time to have your soil tested. Before things get hectic in spring, now is the time to plan for turf renovation. It’s the best time for your laboratory, too, because testing work slows down in winter. You’ll get your results faster too.
Many turf managers worry that winter is too early for testing, and wait until spring before sending off their samples. This has the disadvantage that they squeeze themselves out of enough time to get the best turf results. Surprisingly, soil characteristics (pH, salinity, organic matter content, CEC and so on) change only slowly over a timescale of months (even though they can change rapidly from day to day). So testing in winter will return virtually the same results you’d get in spring, only you get them back faster and with plenty of lead time to plan. You also get the opportunity to shop around and get the best price for the materials the testing has identified as needed.
New versus established turf
As we saw in our first article in this series (Moisture retention and CEC in sandy soils), there can be good reasons for establishing turf or crops on sandy soil, but sandy soil has virtually no capacity to hold nutrients, which end up polluting groundwater and have to be replaced frequently.
New sand tables have different characteristics from long-established grounds, so their management requirements differ too. Two physical characteristics are important to the difference: air-filled porosity and capillary porosity.
Click here for the differences between managing new turf and established turf (600 words, 2 minutes)
Salinity
Soil salinity is a problem confronting many farms in sub-humid and semi-arid zones of Australia. The origins of the salt are natural, and very large reserves lie in many subsoils and aquifers in Australia. Soil salinity is a natural feature of the Australian landscape, but farming and clearing have increased the salt levels in many soils.
Salts are moved into and out of soil profiles by water. There are essentially two types of salinity: irrigation-induced salinity and dryland salinity.
Click here to learn how to measure water salinity and soil salinity (800 words, 3 minutes)
Nitrogen behaviour in the environment
Plants need many different nutrients, notably nitrogen, phosphorus and potassium (“NPK”). This article outlines some basic information about nitrogen and its interactions in the environment from the point of view of manure handling and plant growth.
Nitrogen (N) is a vital element found in all living things. Plants require nitrogen in relatively large amounts, making it the nutrient most often deficient in agricultural and horticultural production systems.
Managing nitrogen inputs to achieve a balance between profitable plant production and minimizing nitrogen loss should be every manager’s goal. The behaviour of nitrogen in the soil system is complex, yet understanding the basic processes can lead to more efficient nitrogen management.
Click here to read more about the nitrogen cycle and how to minimise losses (1000 words, 4 minutes)
Did you know ... ? – Saffron
Saffron is the world’s most expensive spice by weight, at a price ranging widely (depending on production and quality) from $2500/kg to $150 000/kg. The price reflects the painstaking labour required to harvest it.
Saffron is the stigma (the female part) of the flower of the autumn crocus, Crocus sativus. Every flower produces 3 stigmas (or stigmata), which must be plucked by hand from the freshly opened flower. Lower-quality saffron retains the style, which is the stalk of the stigmas. The style is yellow to white and adds nothing to the colour, flavour or aroma of the saffron. The best saffron has had this part removed (by hand), leaving filaments about 1 cm long.
Good-quality saffron is sold as the whole stigmas. Beware of powdered saffron, which can contain anywhere up to 100% food colouring.
About a quarter of a million flowers are required to produce 1 kg of saffron. A typical harvest is 120 g/ha.
About 95% of world production comes from Iran – about 150 t per year. Most of the rest comes from Greece, Morocco, Kashmir, Spain and Italy. Australia has been producing saffron since 1995, when a single farm began developing the management techniques. Now Australia produces about 5 kg per year, mostly in Tasmania. In contrast, Australia imports about 800 kg of saffron annually, at a value of $14m.
Saffron has been deliberately grown for about 3000 years, but evidence of the use of its wild ancestor goes back about 50 000 years. Cultivated saffron is a sterile triploid not known in the wild.