NZ influence on UK farming takes a new step

New Zealand's influence on UK farming took a fresh turn in January when David Law of Forward Farming spoke at a series of field days about effluent ponds and soil health, grassland and cow productivity. Here's what UK agri-journalist Phil Christopher reported.

For a reliable indication of how efficiently a dairy herd is working, take a look at the effluent pond. This advice comes from visiting Kiwi farmer and consultant David Law. "Contrary to popular opinion, a crust is not inevitable," he told farmers.

"But it does tell you there is something wrong, and that money is there to be won by putting it right. Although straw bedding can make a contribution, this is small in comparison to undigested fibre that has passed through the cows and forms the crust."

An approach developed by Mr Law is to think of a dairy system as four interconnected parts - soil, grass, cows and effluent - which he calls a BioCircleâ„¢. "Fundamentally, this begins and ends with the soil and the ways in which it affects grass quality," he explains. "Whether grazed or conserved, this impacts the cows, then effluent impacts soil biology, either for good or ill."

Starting with the soil, Mr Law advocates two main steps: "First, have you soil analysed, not just for pH, nitrogen, phosphate, potash and sulphur, but also 12 addition elements covered by the Kinsey Albrecht system. Based on this, with independent interpretation and advice, make a plan to correct soil pH to 6.4 in conjunction with correcting mineral imbalances, particularly calcium and magnesium.

"Next, consider the impact, not always for the better, of your effluent on soil and grassland. From a crusted store, even after breaking up with a stirrer, it is likely to be dominated by anaerobic bacteria that have proliferated during prolongued oxygen deprivation caused by the crust.

"Not only will the foul smell upset your neighbours, this septic, acidic and toxic soup will contaminate your topsoil and damage its delicate population of micro-organisms, which are critical for growing healthy, high nutrient and palatable grass.

"First, correct pH to 7.4, otherwise it will continue to acidify (lower the pH) of your soil. Make sure you use the right sort of lime and correct quantity for this, consistent with the soil analysis and corrective action plan."

Instead of burning diesel to tackle problem crusts, David Law uses a bacteria and enzyme cocktail imported to New Zealand from the UK, where it was developed by Envirosystems. "If you correct effluent pH and follow the instructions exactly, you will see the crust gradually disappear," he says. Time-lapse photography of this taking place can be seen at https://youtu.be/GDCzic2KhXY.

"After a few weeks, you end up with 100% liquid that is easy to spread with little odour. When they first see this, farmers can't believe where the solids have gone. The answer is that they've been digested by the effluent bugs and converted into aerobic bacterial organic matter, suspended in the liquid. On the surface, it looks like pond water.

"That bacterial matter is nectar to soil organisms. It promotes oxygenation of the soil and, as it breaks down, releases a rich supply of nutrients that feed soil organisms and plants alike."

In the resulting pH-corrected, chemically balanced and biologically active soil, David Law's BioCircle sees nutritionally optimal grass being produced. When fed fresh or conserved, this balanced forage is ideal for the cow's rumen, where most of the fibre content is broken down to release nutrients. The more completely this happens, the more milk cows will produce.

The resulting dung has a much lower fibre content than before. This creates effluent that doesn't crust. Instead, it remains aerobic and, with stimulation from effluent bugs and enzymes, powers the BioCycle around its next revolution.

On his own farm with this system, David Law witnessed around 33% increase in grassland productivity from 14 to 19 tonnes of dry matter per hectare, at the same time as reducing fertiliser from 150 kg N per hectare to 30 (an 80% reduction). He says this transition saw a corresponding increase in clover content to about 35 per cent of the sward, ideal for combining herbage yield and protein content.

Following his UK visit, the company that developed and manufactures SlurryBugs, Envirosystems, is franchising the BioCircle concept from David Law. Clearly, this adds to a long list of changes-for-the-better exported by New Zealand to UK farming.


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