Paul Phillips gets back £6 for every £1 spent on Digest-it® | Kelvin Cave Ltd

Digest-it® boosts slurry value

Paul Phillips gets back £6 for every £1 spent on Digest-it®

Digest-it treatment boosts slurry value

Increasing the fertiliser value of slurry from the pig finishing unit on Brian and Paul Phillips’s 670 acre Bridge Farm, Northallerton, is showing good results part-way through a 12 month trial period. They have been treating the slurry in the under-floor storage tanks of their slatted pig-finishing houses with Digest-it®, a live culture of aerobic bacteria. So far, before and after treatment analysis has shown a 6:1 return on the investment in Digest-it in terms of artificial fertiliser replacement value.

Bridge Farm is a mixed enterprise growing cereals, fattening beef cattle and lambs, and running a 200 sow unit with progeny taken through to finish in slatted finishing units. Introduction of NVZ regulations in 2002 raised awareness of the fertiliser potential of the pig manure, and careful consideration of crop nutrient requirements has increased the earning potential of the pig enterprise.

The aerobic bacteria in Digest-it break down slurry solids, releasing the potash and phosphate and converting ammonia nitrogen into organic, plant-available nitrogen. Because increased aerobic microbial activity in the store reduces the levels of the putrefying toxic anaerobic bugs, slurry is converted from a smelly waste to a valuable source of nutrients which supports soil fertility and health, and reduces ammonia and smell emissions.

The results of the first 4 months’ treatment are shown below.

PIG SLURRY
ANALYSIS Date:

03/02/12

07/06/12

Difference

Sample No.:

244

296

Sample ID:

Pre-Treated

Post-Treated

Total Nitrogen %

0.600 0.836

+39%

Total Phosphate %

0.125

0.054

-57%

Total Potash %

0.404

0.688

+70%

Slurry Fertiliser Value £/m3

5.87

8.53

+45%

Digest-it Input Cost £/m3

---

0.36

---

Net Benefit

+5.87

+8.17

+2.30 (+48%)

*Slurry Fertiliser Value is based on the following fertiliser unit prices, Nitrogen - £0.96, Phosphate - £0.70, Potash - £0.70.
Digest-it is priced at £8.00 per litre, with an application rate of 1 litre per 22m3 of slurry.
Conclusion:
Digest-it treated slurry has improved the fertiliser value by £2.30 per m3 at an input cost of £0.36 per m3. This represents a cost effective ratio of 6.4:1.

Slurry is removed from the under-slat storage tanks twice a year; in February, when it is injected into silage ground, and again in the summer onto stubble turnip fields. In the past, stirring the slurry has had the potential to cause problems with the pigs housed above it, due to the release of ammonia and other noxious gases. Smell has also been a problem when application to land near housing has been necessary. Digest-it reduces smell significantly, and also helps to keep the slurry in a homogenous liquid state, reducing or eliminating the need for agitation, and making injection easier.

Digest-it is supplied as a liquid which Paul dilutes and pours into the slats from a watering-can once a week. “So far the analysis has shown a really worthwhile improvement,” says Paul, “and with fertiliser costs increasing, every little helps."

Paul Phillips gets great results from Digest-it from Kelvin Cave Ltd
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