Conal’s Pasture Research, Part 2: Dry Matter Results
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Time to read 8 min
The dry matter results are back. The higher pasture harvests recorded in Conal Wattam’s first cut remain after accounting for moisture.
Using independent Hill Labs measurements from pooled treatment samples, all three Fungal Feeder rates recorded higher estimated dry matter harvests than their corresponding controls across the three research areas. It is an encouraging early pattern, with the sampling method and soil variation important to understanding the figures.
Part 1 covered the first cut and Conal’s observations from the paddock. Part 2 brings the dry matter results together with those field measurements and DairyNZ’s historical Northland pasture growth benchmarks.
Dry matter percentage and dry matter harvested answer different questions.
- Dry matter percentage (%): how much of a fresh sample remains after removing its water.
- Dry matter harvested (kg DM/ha): how much dry pasture was collected, scaled to the area sampled. This uses both the fresh weight collected and its dry matter percentage.
The control had the highest dry matter percentage, but the lowest estimated dry matter harvest within each of the three areas. Every Fungal Feeder treatment remained above its own area's control after applying the pooled laboratory percentages.
See the harvest comparisons first. Then see how the percentages are used.
How the first cut was measured
Fungal Feeder was applied on 5 September 2026, at 30, 60 and 90 litres per hectare alongside untreated controls. The first-cut measurements were collected on 5 and 6 October 2026, approximately one month later.
Conal used 1 m² sampling areas and a hedge trimmer, cutting to approximately 2 to 3 cm. Each treatment had five samples in Areas 1 and 3, covering 5 m² per treatment, and three samples in Area 2, covering 3 m² per treatment.
The kilogram figures below are combined fresh pasture totals for those samples. Pasture sent to Hill Labs was pooled by treatment across all three research areas, giving one laboratory dry matter result for each treatment.
| Research area | Sampled area per treatment | Control | 30 L/ha | 60 L/ha | 90 L/ha |
|---|---|---|---|---|---|
| Area 1 | 5 m² | 3.10 | 3.20 | 4.25 | 6.50 |
| Area 2 | 3 m² | 1.30 | 1.90 | 2.75 | 3.40 |
| Area 3 | 5 m² | 1.10 | 2.10 | 3.70 | 3.10 |
Estimated dry matter harvested in the first cut
For each treatment, we multiply the combined fresh weight by its measured dry matter fraction, divide by the sampled area, then convert to a hectare equivalent.
The calculation
Estimated kg DM/ha = combined fresh weight in kg × treatment dry matter fraction ÷ total sampled area in m² × 10,000.
For Area 1 at 90 L/ha: 6.50 × 0.205 ÷ 5 × 10,000 = 2,665 kg DM/ha.
| Research area | Control | 30 L/ha | 60 L/ha | 90 L/ha |
|---|---|---|---|---|
| Area 1 | 1,538 |
1,555 (+1.1%) |
2,091 (+36.0%) |
2,665 (+73.3%) |
| Area 2 | 1,075 |
1,539 (+43.2%) |
2,255 (+109.8%) |
2,323 (+116.2%) |
| Area 3 | 546 |
1,021 (+87.1%) |
1,820 (+233.7%) |
1,271 (+133.0%) |
Harvest estimates are rounded to the nearest kilogram. Percentages use the unrounded estimates and compare each treatment with the control in the same area. Sampled areas per treatment were 5 m² in Areas 1 and 3, and 3 m² in Area 2.
Each area estimate uses the pooled dry matter percentage for that treatment. Individual areas may have differed in moisture content. These are calculated harvest estimates, rather than separate laboratory measurements of yield for each plot.
Dry matter percentage: how fresh weight is converted
A higher dry matter percentage means a drier sample. The amount harvested also depends on how much fresh pasture was collected. The control's 24.8% means 248 g of dry matter in each kilogram of fresh pasture. At 90 L/ha, 20.5% means 205 g per fresh kilogram. Those percentages describe equal fresh weights, while the actual harvested weights were different.
Hill Labs certificate 4334434, reported on 13 October 2026, gives the following dry matter percentages for the four mixed-pasture samples. The laboratory method was weight loss on drying at 105°C for a minimum of 24 hours.
| Treatment | Lab sample | DM as % of fresh weight | DM in 1 kg fresh pasture |
|---|---|---|---|
| Control | 4334434.4 | 24.8% | 248 g |
| 30 L/ha | 4334434.3 | 24.3% | 243 g |
| 60 L/ha | 4334434.2 | 24.6% | 246 g |
| 90 L/ha | 4334434.1 | 20.5% | 205 g |
For example: two harvests from the same sampled area.
In Area 1, each treatment was sampled over 5 m²:
- Control: 3.10 kg fresh pasture × 24.8% = 0.7688 kg estimated dry matter.
- 90 L/ha: 6.50 kg fresh pasture × 20.5% = 1.3325 kg estimated dry matter.
The 90 L/ha sample had a lower dry matter percentage, but more fresh pasture was collected. After accounting for its water content, it still had more estimated dry matter in that harvest. These totals correspond to approximately 1,538 and 2,665 kg DM/ha respectively.
This is one worked example. The table above includes all treatments and controls, including the small 1.1% difference at 30 L/ha in Area 1.
The 90 L/ha pooled sample contained more water per fresh kilogram, so its percentage difference from the control reduced after conversion to dry matter. Its estimated dry matter harvest remained higher than the control in all three areas. Each treatment's pooled percentage is used for that treatment in all three areas.
This report adds dry matter, with nutritional composition still to come.
The certificate covers dry matter only. Protein, metabolisable energy, fibre and mineral results would add the information needed to assess feeding value alongside the amount of pasture harvested.
How the treatments compare with their controls
All nine treatment estimates remain above their corresponding controls after the moisture adjustment. The size of the difference varies considerably:
- Area 1: 30 L/ha was only slightly higher, at +1.1%. The differences were +36.0% at 60 L/ha and +73.3% at 90 L/ha.
- Area 2: the differences were +43.2%, +109.8% and +116.2% at 30, 60 and 90 L/ha respectively.
- Area 3: the differences were +87.1%, +233.7% and +133.0%, with the highest estimated harvest at 60 L/ha.
The highest estimate was at 90 L/ha in Areas 1 and 2, and at 60 L/ha in Area 3. An optimum application rate has not been established. Further replicated comparisons will help show whether the pattern repeats across different soils and growing conditions.
Putting the figures in Northland context
DairyNZ’s historical Northland pasture growth data give a seasonal reference. The September and October daily averages below have been multiplied by 30 to show an illustrative 30-day growth equivalent.
| Site | Monitoring period | September kg DM/ha/day |
September kg DM/ha over 30 days |
October kg DM/ha/day |
October kg DM/ha over 30 days |
|---|---|---|---|---|---|
| Awanui | 2010-2015 | 58 | 1,740 | 70 | 2,100 |
| Okaihau | 2012-2015 | 37 | 1,110 | 47 | 1,410 |
| Dargaville-NARF | 2008-2016 | 52 | 1,560 | 64 | 1,920 |
| Tomarata | 2010-2014 | 30 | 900 | 45 | 1,350 |
Across these four sites, September’s equivalent ranges from 900 to 1,740 kg DM/ha over 30 days, and October’s from 1,350 to 2,100 kg DM/ha over 30 days. These are historical site ranges, rather than a current regional average, a confidence interval or a performance target.
A first harvest and monthly growth measure different things.
Conal’s first cut measures pasture harvested above the cutting height. It may include pasture already present before application. A starting pasture measurement and subsequent regrowth measurements would be needed to establish how much grew during the month. This first cut therefore cannot establish monthly growth or show that a treatment outperformed the DairyNZ growth benchmarks.
What this adds to the research
The encouraging finding is that the observed harvest differences persist after applying the measured dry matter percentages. The next question is how consistently those differences occur, and how they relate to Fungal Feeder, soil conditions and pasture composition.
Conal observed soil variation within and between the areas. In Area 1, the 60 and 90 L/ha plots appeared to have more favourable soil conditions. Those differences may have contributed to the pasture harvested. Further replication, consistent sampling and soil measurements will help us investigate the connections and distinguish a possible treatment response from other influences.
The Hill Labs results provide the measured moisture adjustment used in our calculations. The per-hectare harvest estimates are Bio Charge calculations from those percentages and the field records. They are early observations from one cut, with pooling and soil variation important to their interpretation.
What happens next?
The next stage is to build the picture through further measurements:
- Regrowth over known periods: repeat cuts with consistent cutting heights and record management changes, including any aeration, so comparisons can be interpreted.
- Further replicated research: repeat treatment and control comparisons to assess how consistently the differences occur.
- Pasture and soil information: bring in nutritional composition and Soil Foodweb findings as they become available, matched to the relevant samples.
- Proposed soil eDNA testing: explore organisms detected in treatment and control soils, alongside the other soil assessments.
No new Soil Foodweb or eDNA results are included in this update. Soil eDNA remains a proposed next step. Watch this space. We will share further findings as the pasture and soil assessments develop.
On-farm research in the Far North
This research compares Bio Charge Fungal Feeder at 30, 60 and 90 litres per hectare with untreated controls. Meet Conal Wattam and read how the research began.
Want to investigate what is happening on your farm?
If you are farming in the Far North and would like Conal to carry out on-farm research, get in touch with Bio Charge. Tell us about your farm and what you would like to investigate.
Sources and calculation basis
- Hill Labs, Certificate of Analysis 4334434, reported 13 October 2026. Four mixed-pasture samples: control (4334434.4), 30 L/ha (4334434.3), 60 L/ha (4334434.2) and 90 L/ha (4334434.1). Dry matter measured by weight loss on drying at 105°C for at least 24 hours.
- Conal Wattam’s first-cut field records, collected 5 and 6 October 2026. Combined fresh sample totals and pooling by treatment across all three areas confirmed by Bio Charge. Hectare estimates and percentage comparisons calculated by Bio Charge.
- DairyNZ, Average pasture growth data: Northland. Historical site records spanning 2008 to 2016. Published daily averages multiplied by 30 for the illustrative growth equivalents. Source checked 15 October 2026.
