Soils For Life Webinar - Plant Sap Testing and Analysis

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The South Australia Paddock Labs project
Over the last several decades Australian crop growers have been increasingly challenged by rising temperatures and input costs, increasing rainfall variability, and declining soil health. Improving soil health is widely recognised as a key mechanism to address these challenges, not least for improving drought resilience. Healthy, functioning soils store water by acting as a sponge. Innovative Australian croppers have been leading the way to build healthy soils for drought resilience. In this ‘Paddock Labs for Drought Resilience’ project (2021-2022), we supported experimentation with, and adoption of, drought resilient cropping practices in South Australia.
This episode: Sap analysis
Sap testing is an emerging practice, where farmers are measuring the sap in plants for indicators of current nutrition, such as total sugars, potassium, calcium, magnesium, sodium, ammonium, nitrogen, etc. Two farms implemented a sap analysis program, with four demonstration sites on Eyre Peninsula also having some exploratory analyses conducted. Most of the participants used visual tests to determine the health of the crops and soil. As part of the Paddock Labs project, Soils for Life hosted a webinar on sap testing with Mark Tupman, a horticulturalist from Productive Ecology. Because sap testing is quite technical, expert advice is often recommended.
More information
This project is supported by Soils for Life, through funding from the Australian Government’s Future Drought Fund. To learn more about the South Australia Paddock Labs here: soilsforlife.org.au/south-aus... Contact us at soilsforlife.org.au/ for any further information.
0:00 Introduction & instructions
1:15 Introduction to sap testing
1:58 Mark Tupman explains sap test results
2:15 Nutrient mobility in plants
3:23 Reading: Total sugars
4:34 Reading: pH levels
5:20 Reading: EC - Electrical conductivity
6:04 Question: What EC levels would indicate water stress?
6:42 Reading: Potassium
7:35 Reading: Calcium
8:40 Nutrient description chart
11:36 Soils in South Australia
14:50 Protein absorption and Nitrates (N)
16:25 Ammonium
17:38 Improve conversion to Nitrogen
18:17 Increasing photosynthesis for conversion
18:56 Question: Timeframe of Ammonium conversion
20:13 Calcium and Magnesium issues
24:53 Phosphorus levels and EC
31:18 Not all soil treatments affect plants
32:09 Question: Nitrate discrepancy
34:32 Is Sodium affecting Nitrate conversion?
36:53 Any other questions?
37:18 Question: Does EC affect all other nutrient access?
38:42 Question: Can you use soil biology to balance nutrients?
41:10 Question: Does Manganese and Iron stimulate photosynthesis?
43:07 Question: What is the role of Silica?
45:15 Question: What is the role of Sulphur?
45:52 Question: Does improving soil health increase profits?
47:30 Inputs don't necessarily show up in sap tests
48:09 Increased plant resilience again pests
49:05 Sap analysis efficacy
50:54 Sap levels in relation to soil type and condition
58:34 Benefits of seed coatings
1:00:21 Formulating effective foliar sprays
1:05:15 Thank you and acknowledgements
#soilsforlife #paddocklabs #southaustralia #cropgrowers #soilmentorapp #nicolemasters #soilmonitoring

[@marktupman7867]

Mark Tupman 1 second ago Following this webinar, we have found out that the total sugar levels include all forms of sugar in the plant sap. The EC levels on the are an indication of total ionic nutrients. Brix readings, on the other hand, are indicative of both total sugars and total ionic nutrients. Remember that high levels of things like potassium or sodium can spike EC levels so higher Brix readings don’t always correlate with high sugar levels or a good nutritional profile.

[@ChristopherBurman-ie2lk]

@Mark Tupman. Many thanks for this. I have just emailed your office for the Nutrient mobility in plants sheet and any other open source information. I'm a smallholder in South Africa trying to learn about interpreting sap analysis and found this webinar to be one of the best i have come across so far. Many thanks indeed for the insights.

[@ChristopherBurman-ie2lk]

I should have written: the best vid i have come across. Unfortunately, my sap did not provide a total sugar level analysis

[@christopherburman3340]

Thank u for info sheets