Question and Answer


Hi Tom,

Thanks for the correspondence. I hope you won't mind answering a few more questions for me. This year we have changed tack with our fertiliser regime, instead of 500kg/ha 15% super phosphate annually and 2500kg/ha lime every third year, and about 100kgN/ha/yr.

This year we came across Probitas (The Probitas System) and have taken some advice from them. I have noticed that like them a lot of other people are advocating getting the Ca and Mg base saturation levels up. I am still not entirely sold on the electrolysis side of soil that probitas promote.

This year we dressed the whole farm with 2500kg/ha lime in January and intend to follow up every year with 1000kg/ha lime. We used a Probitas brew on 120ha. This brew had a large amount of Mg in it approx 500kg/ha by memory. We farm on heavy clay and part of the farm is a podzol clay.

We winter milk 220 cows on 220ha and consequently usually use Urea, Ammo, SOA, sustain....N in some form to grow grass about now! This season I am trying to stay away from N fertiliser. I am worried there will be a few year transition period, until I can get the soil biology going to replace the synthetic N.

Q1. If I use your bio-sea brew now will I see a growth effect this winter?

A: Yes you will, as long as your soil temperature stays above 10°, preferably 13+°. Northland is ideally situated for biological agriculture with good temperature, daylight hours and rainfall. In fact it’s better suited to biological agriculture than the water soluble fertilisers you’ve used in the past.

Under the Probitas system your fertiliser dollar will be spent on balancing your calciums and magnesiums, balancing the trace minerals, making phosphate available, increasing your soil biological activity, increasing organic matter levels and water holding capacity. All of these will lead to a more sustainable farming practice.

The role of Biosea in conjunction with this system is to grow grass and clovers by assisting with cell division in plant/root systems and increasing symbiotic fungi for better plant health and soil health. Grazing dairy cows will return 25% of what they consume back over the pasture. They also eat a fair amount of dirt/soil. Under the Biosea/Probitas system the soil is teeming with good bacteria and fungi. Once this enters the rumen it helps in processing the dry matter they’re eating.

This is how a ruminant obtains its energy and its ability to make proteins. It does not get these from straight grass alone.

Q2. How often do I need to dress with bio-sea?

A: Most of the dairy farmers using Biosea/Probitas use it 2 or 3 times a year, usually spring and autumn and some do another round after the second round of grazing as this is a critical time for mating. They use 10 – 15 litres per hectare each time.

Q3. Is using Bio-sea with urea a good option or am I negating the good effects of bio-sea?

A: For farmers in your position, who have been heavily dependent on Urea as a nitrogen fertiliser I advise at the start to mix the 2 together. It would probably be better to switch from urea to calcium nitrate. This is slightly more expensive but it does work better.

Using urea at this point at low levels of 6kg per hectare will have absolutely no detrimental effect; in fact will be of value as the N in urea will become tied to a fish protein/carbon. This will enable the N to be freely available and help with plant growth.

If you use seaweed as part of this mix it will be a valuable combination as it will assist in developing your soil/plant algae. Algae is the most abundant micro-organism on the planet and is responsible for photosynthesis, stabilizing blue/green algae which assist in fixing biological/atmospheric nitrogen. It will also help with soil health and consequently animal health. Use a dry powder seaweed at about 0.5 – 1kg per hectare, which mixes easily into your spray tank. This is the most cost effective means of gaining a greater diversity of soil biology. (With liquid seaweed you’re paying for a hell of a lot of water to be transported around).

Q4. The half of the farm that has not had the Mg dressing, will it respond to bio-sea or should I continue my old ways with Urea?

A: Magnesium is the central atom of chlorophyll. It is extremely important for photosynthesis. It also plays a great part in animal health, reproduction and freeing up compacted soils to give better aerobic respiration and better root development.

If you continue using urea on the block that has not had magnesium not only will you lack the benefits of magnesium but you will continue to compact the soils, have increased thistle and weed problems, distinct loss of soil biology, problems with animal health and conception and above normal empty rates.

You should cut back or stop using urea on the block without magnesium. You will need to give consideration to when is the best time for you to do this. You can use Biosea on this block, it will respond well. You should add magnesium sulphate, which is easily accessible, cheap and a very good product to spray in conjunction with Biosea and cal nitrate/urea.

Q5. In your experience is there a transition period, or will that Probitas brew have made a significant difference to soil bio already? Should i expect a big production drop?

A. There can be a period of slightly lower milk production at the start of the season using this system. This is because when you throw as much energy as the soluble salt fertiliser programmes do into any soil you will get a response, and it will be fairly quickly. The problem is when you use urea/nitrogen at these levels you burn up all your biology and the carbon in the soil.

You could look at it like this – you have a big wonderful open fire in your lounge burning nice dry old man pine. You look at the fire and say how well the wood is burning. The reality is it’s the oxygen it’s sucking out of the air that is responsible for the effect. It’s the same with urea/nitrogen; it’s sucking the oxygen and biology out of the soil and leaving you a wasteland.

By the time the season finishes you will not lose production using Probitas. At the end of the season what you’ve lost in the initial period you will gain with diversity of species in your grasslands, better water holding capacity over the summer, better milk production via the clovers and better soil and plant health over the season. At the end of the first year, by the time you add up your production, empty rates, vet bills etc I would expect you’ll have an increase in bottom line return.

Regards the question will I experience a production drop? Overall no, but you must decide, are you farming for production or profit?

Other points. You should subscribe to Acres USA magazine. It’s a great magazine that will give you a balanced insight into biological agriculture. It’s produced by farmers, for farmers.

The specific types of biology that have been fermented into Biosea will colonise your soils and will help reduce incidence of somatic cell count and mastitis. You previous use of large amounts of N fertiliser will have led to increased blood/urea nitrogen levels (BUN). Urea is an oxidising agent. It’s marked on the bag as being so, and is classed as dangerous goods when being shipped.

With the amount that you’ve been putting on your pasture your grass will be high in nitrogen. Do not confuse this as being high in protein. High levels of nitrogen in grasses lead to high BUN levels in ruminant animals. This leads to empties and all sorts of bad bacteria in the milk and cows that cannot detox their livers. It is the single biggest causes of high milk/urea/nitrogen levels (MUN). There’s absolutely no doubt that overuse of urea stuffs the soil, soil biology, animal health and ultimately has a detrimental effect on the quality of the milk. I’d be happy to discuss this further with you on the phone if you’d like to carry on the conversation.

Our website is Have a look at the Omega+ Dairy oil page, you should find it interesting.

Looking forward to talking to you again, regards Tom
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