Ponded Pasture Research

Ponded Pasture trials on a property at
Kunwarara, Central Queensland

Healthy Soils Inc in conjunction with a grazier commenced a number of trials on a property at Kunwarara, Central Queensland to determine best practice management of ponded pastures in January 2013.

 

La Motte Test - dry pasture

Explanatory Notes: The La Motte Test utilises a mild extraction solution which is a closer approximation to the gentle acids exuded by the plant roots and micro-organisms to solubilise minerals. The La Motte test gives an indication of the amount of plant available nutrients at the time of sampling (Levels are not really relevant in soils with a TEC below 5) Clay Loam Brownish sampling.

— o O o —

Sample 1 Soil Indicators — Aleman:shallow


Key Microbe Groups

Comments
The total mass of microbes in your sample was good. Biomasses of other key desirable microbe groups ranged from poor to fair (Total fungi), to good in the case of Pseudomonas, Actinomycetes, etc. True anaerobes were elevated, which indicates that this soil was recently waterlogged or compacted. Protozoa were good, they are a good indicator of soil health, they are important for nutrient transfer and cycling between soil trophic levels and can be sensitive to agrochemicals.

The Fungi to Bacteria ratio was fair due to the low fungal biomass compared to the high bacterial biomass. Overall microbial balance was good but could be improved. These results suggest that management practices should initially focus on building general fungal biomass. Re-test periodically, and once biomass has improved concentrate on any key desirable groups that remain low.

Explanations
The Microbe Wise test measures the biomasses of key microbial groups directly from your sample. It uses molecular ('DNA type') technology to analyse the unique cell membrane 'fingerprint' of each microbe type to identify and quantify key groups important to soil processes. This method is more accurate and precise than other methods, such as direct microscopy or plate culture, because it uses chemical extraction to remove the maximum amount of microbial material from the sample and is repeatable to 0.01% between replicate analyses. It measures organisms that are alive or recently dead (within a few days).

Always compare your results with a control sample. Guide values are included as a help, but because a large number of factors affect microbiology the guide levels may not be optimal for your specific conditions.

— o O o —

Sample 2 Soil Indicators — Paragrass:shallow

Key Microbe Groups
Comments
The total mass of microbes in your sample was good to fair. Biomasses of other key desirable microbe groups ranged from poor (Mycorrhizal fungi), to good in the case of Total bacteria, Pseudomonas, etc. Mycorrhizal fungi are important for nutrient solubilisation and nutrient transfer and you may be missing on these benefits. Total Fungi were fair. Protozoa were good, they are important for nutrient transfer and cycling between soil trophic levels, and can be sensitive to agrochemicals, particularly herbicides. True anaerobes were elevated, which indicates that this soil was recently waterlogged, or compacted. The fungi to bacteria ratio was fair due to the low fungal biomass. Overall microbial balance was good, but could be improved as fungi levels were fair.

These results suggest that management practices should initially focus on building general fungal biomass. Retest periodically, and once biomass has improved concentrate on building microbial diversity and biomasses of any key desirable groups that remain low such as Mycorrhizal fungi.

— o O o —

Plant leaf analysis report — 3 Samples

1. All analysis is dry weight - Samples dried at 70˚C for 24hours prior to fine grinding
2. Unless requested, leaf samples are NOT washed to remove salt spray or liquid fertilizers prior to analysis
3. Samples are microwave digested with nitric acid and read on the ICP-MS
4. Carbon/ Nitrogen/ Sulfur measured using a LECO CNS2000 Analyser
5. mg/Kg = ppm
6. By Calculation:- Crude Protein = %N x 6.25
7. Nitrate/Ammonium/Chloride measured on a water extract.
8. Moisture based on sample dried at 105˚C

— o O o —

Initial Leaf Tissue

Comments
As these grass species are not well researched, ideal nutrient levels are not available. Therefore the best indicator of performance of each trial site is through direct comparisons between same species at different sites and by looking at nutrient contents before and after treatment.

The initial analysis outlined on the previous page shows various significant differences between both the major and micro nutrients across the three samples. Most notably, comparing the two Aleman samples; Site 2 (represented by Green) is higher in sodium, potassium, iron and manganese while Site 1 (Blue) is higher in calcium, sulphur, phosphorus and nitrogen. Looking at the two different species at Site 2; (Aleman and Hymenachne) calcium, sulphur, phosphorus, nitrogen, iron, manganese, zinc and copper are at higher levels in Aleman (Blue) when compared with Hymenachne (Red). This could possibly indicate that Aleman, by its nature, is a more nutrient rich species than Hymenachne. At the time of sampling Aleman (Site 1) showed the highest crude protein levels.

— o O o —

Kunwarara Trial
The following graphs have been compiled from the data collected by the Healthy Soils Group at a Kunwarara property on the 10th March 2013. In January 2013, a Kunwarara grazier conducted a number of trials to ascertain which nutrients or microbial products would achieve the best paddock result. The trial was comparing 3 foliar treatments (1,2,3) and two spreading treatments (4,5) as well as a 2012 (chook manure) treatment and a test of Rhodes grass at the cattle yards (yards)

pH variation
Figure 1. pH levels of Pastures

• The ideal pH level is 6.4 with all three water grasses achieving this in trial 1 or 2.
• The three collections of Paragrass in trial 5 had similar pH results 5.5, 5.7, 5.5

Figure 2. BRIX levels of pastures

• The higher the brix level, the healthier the plant.
• Paragrass in trial 1 achieved a brix of 8% and in trial 5 of 7%.
• Large variations in Paragrass brix results (2.5 – 8.0%)

Figure 3. Nitrate levels (ppm) in pastures in each trial. There is no known level of what the ideal nitrate level should be in ponded pastures. The standard being used comes from lucerne (3500 – 5500 ppm). Excess nitrates will make the plant weak and open to insect attack.

• The highest levels of nitrates (2300ppm) were in Paragrass in trial 2 and 5.
• The lowest levels across the pasture species was in trial 1 (490 – 700ppm) where the microbial innoculum was sprayed. This may be because the increase in microbial diversity has enabled the conversion of the majority of nitrates into ammonium for plant uptake.
• Interesting point is that the untreated Paragrass was 1700ppm compared to treated of 700ppm. This alone is showing the impact of the treatment. Possibly more conversion of nitrate to ammonium??

Figure 4. shows the potassium levels (K+) of the various ponded pastures in the trial. Ideal levels for potassium (2500-3800ppm) are extracted from lucerne data.

• The plants with the highest levels of Potassium were Rhodes Grass at the cattle yards.
• The microbial treatment had the lowest levels at 1200 and 1300ppm potassium and the highest at 4500 ppm was the Rhodes grass at the yards.
• Paragrass not sprayed and Hymenachne in trial 1 had the lowest levels of potassium.
• Hymenachne throughout the trial had low results.

see photos

 

— o O o —

Other Healthy Soils Research Projects