News and Opinion
‘News and Opinion’ is just that. It contains posts of important and interesting news relating to agriculture and climate change, water use and quality, soil fertility and fertiliser, and our opinion on these posts. We welcome your opinion on our opinions!
‘The potential of RPR (reactive phosphate rock) for New Zealand’
I have been involved with RPR research and promotion in New Zealand for 40 years. I spent 17 years as a soil fertility research scientist with the Agricultural Research Division of the Ministry of Agriculture – what became AgResearch – including 3 years as Chief Scientist (Soil Fertility) at Ruakura. I designed and coordinated the ‘National Series’ of RPR trials, which ran over a period of up to 8 years on 19 farms throughout New Zealand in the 1980s. The trial sites were all deliberately selected to have below-optimum soil Olsen P levels, to more clearly show any differences in performance. Despite this, differences in pasture production between RPR and super were minimal – 0-3% on average – and had totally disappeared by Year 3 on low and medium P-retention (ASC) soils and by Year 5 on the highest P soils. The only exception was a low-rainfall (700mm), non-irrigated site at Winchmore in mid-Canterbury which
had also been over-limed to a soil pH of 6.4.
The simple solution to any initial ‘lag-phase’ with RPR was proven to be to use a blend of RPR and high-analysis P fertilisers such as TSP, DAP or MAP (and added S as required) for the first few years. Note that mixtures of RPR and superphosphate were shown to be not as effective for this purpose. Subsequent research demonstrated that where Olsen P levels were at or above optimum – as is the case on about 98% of dairy farms and about 75% of hill country farms in New Zealand – there were no measurable differences in pasture production right from the start of using RPR, meaning a a soluble P component is unnecessary.
If the fertiliser industry in NZ was not dominated by the superphosphate manufacturing duopoly, I am convinced that RPR – mixed with sulphur and other nutrients as required for individual farms – would (i) already be the main source of P used in NZ, and (ii) we would have far less polluted waterways and lakes as a result. RPR is proven to result in far less run-off of water-soluble P than superphosphate. Imported high-analysis would be blended in where required.
Also, because RPR particles dissolve in the soil steadily over time, releasing P for direct uptake by plants, there is far less P existing as soluble P adsorbed onto the surface of soil particles than is the case with superphosphate. Most of what is described as ‘particulate P’ lost from soil in run-off and erosion is actually present in the form of
soluble fertiliser P that has become adsorbed (to use the technical term) onto soil particles near the soil surface. When these particles end up in a waterway or lake through soil erosion, as much as 25% of this adsorbed P can easily be desorbed back into water-soluble form, (as demonstrated in an excellent soil chemistry paper by Australians Barrow & Shaw in 1975). This ‘particulate P’ form of loss is also greatly reduced with RPR, but you need multi-year constant-treatment trials to clearly demonstrate this.
Unfortunately, this vital area of water-quality research has received no funding in NZ, largely because most of the government research funding on fertiliser and the environment is – completely inappropriately – channelled through the duopoly, who have no wish to encourage this research. New Zealand simply does not need to be taking the manufacturing-grade phosphate rock from the Moroccan-occupied deposit in the Boucraa area of the Western Sahara to make into superphosphate. Certainly, superphosphate has played a very important part in developing NZ’s low-P soils. However, virtually all our agricultural soils have long been developed to the point where they can now be maintained very easily with slow-release form of P, containing up to 30% soluble P where needed, to ensure that our
waterways are protected.
If we continue to allow the industry to be dominated by two management groups who refuse to accept what is happening to our environment, we will only have ourselves to blame as we progressively lose our hard-earned reputation as a ‘clean and green’ country. Farmers must consider the question ‘Which P fertiliser should I use, and why?’ far more seriously than they have in the past.
Algerian RPR is easily the match of any other RPR agronomically, and contains a low cadmium level of 18ppm, which represents only 140mg Cd per kg P, well under the Biogro’s and Demeter’s organic farming limits, and only half the limit that the industry allows itself. It performed even better than North Carolina RPR in trials run by the
International Fertilizer Development Center, Alabama, USA. The Managing Director and the Senior Scientist of the IFDC released the following statement in 1999: “Unground Djebel Onk (Algerian) phosphate rock is classified as a
highly reactive phosphate rock for direct application to acid soils”.
All NZ soils are acid. As it happens, all RPRs are also liming agents in their own right, automatically reducing and in some cases going close to eliminating the need for maintenance lime applications. Algerian RPR has the highest lime equivalent (58%) of all RPRs, helped a bit by the small amount of naturally-occuring dolomite running through the
deposit (3-7% by weight). Note that the naturally-occuring 3-7% phosphatic dolomite in Algerian RPR can reduce its citric acid solubility in NZ’s current but obsolete 30-min test. This is an artefact only, and has no effect whatsoever on the excellent field performance of Algerian RPR. It also contains among the lowest levels of Cd, mercury (Hg) and uranium (U) of all IFDC-recognised RPRs.
Because of all these positive attributes, some industry players have tried to put farmers off using Quinfert Algerian RPR by playing the ‘it is not soluble enough in NZ’s test’ game. So we also offer the product with some of the dolomite screened out, to ensure it reaches 30% citric solubility in the current test. Both the normal (V1) and ‘low-Mg’ (V2) versions perform the same as each other in the field as fertilisers, i.e., exceptionally well. One just has a bit more dolomite than the other!
Finally, there are several other low-Cd RPRs available for blending from around the world as well, so there is absolutely no reason for anyone to resort to reducing the high cadmium level in Sechura RPR by mixing it with a low-Cd manufacturing -grade (non-RPR) phosphate rock, which may be as little as 20% as effective as an RPR.
A 50/50 blend of Sechura with Boucraa slimes (PB3) or Moroccan rock may be only 60% as effective agronomically as 100% RPR. And take note, the Khouribga rock from Morocco, commonly used in the manufacture of fertilisers, can contain large amounts of uranium, up to 566 ppm (FAO, 2004). This is so high (10 times higher than Algerian RPR for example), it can be economically mined to produce uranium! Ask for an updated declaration of the heavy metals in your superphosphate.
The ball is in your court. Please phone or email me if you have any questions.
Dr Bert Quin
021 427 572
The Algerian RPR (often named after the name of the nearest village, Djelbel Onk) has been rated as a “highly reactive phosphate rock suitable for direct application” by the world’s foremost authority on the use of various phosphate rocks as P fertilisers directly, the International Fertilizer Development Center (IFDC) in Muscle Shoals, Alabama, USA.
The IFDC are the experts in assessing the geological and geochemical make-up of phosphate rocks. This assessment is necessary to determine whether a phosphate rock is an RPR or not. The IFDC state that there is no simple laboratory solubility test that can automatically assess whether a phosphate rock is a true RPR or not. In particular, the presence of even small percentages of free lime or dolomite in a sample of a true RPR can give an artificially low ‘solubility’ in some tests, and caution is required in interpreting such analytical results.
Pastoral Robotics Ltd was very excited to have its first farm-scale, farm-ready 8 metre wide Spikey on display at the 2017 National Fieldays, June 14-17.
Designed for 3-point-linkage tractor mounting, this equipment for detecting fresh urine patches and same-pass treating them its patented ORUN spray takes less than 10 minutes per ha to control the biggest threat to ongoing consenting of dairy farming; nitrate leaching from urine patches.
Using technology developed here in New Zealand by Pastoral Robotics founders Geoff Bates and Bert Quin, Spikey can detect and spray fresh urine patches on a follow the cows basis. The recovery by pasture of the huge amount of urine-N deposited in urine patches (400-1000 kg N/ha within the patches) is increased by an average of 70%, automatically greatly reducing nitrate-N leaching, increasing pasture growth, and reducing fertiliser N requirements.
Even better, the Spikey equipment can be purchased fitted with a hopper and auger-fed spinner specifically designed to spread fertiliser N using the patented ONEsystem. Instead of very inefficient granular urea, the state of the art ONEsystem uses wetted, nbpt urease inhibitor-treated prilled urea, reducing N application requirements literally by half, averaged over independently-conducted, scientific designed and published field trials under grazing.
Canterbury to California; challenges for water supply and quality
I attended the second California-based International Groundwater Quality Conference in the last week of June. I gave an address on the new Spikey® technology for the detection and treatment of cow urine patches to reduce nitrate leaching. Geoff Bates and I, through our company Pastoral Robotics Ltd, have been developing this technology for the last 3 years. Attending this conference was a bit of ‘déjà vu’ for me, as I cut my career teeth as a MAF scientist in mid-Canterbury in the 1970s investigating the effects of land use on groundwater quality.
Amazingly to all non-Americans attending the conference in San Francisco (and in fact to most Americans from outside California), until very recently the State had few laws or regulations covering the extraction and use of its precious groundwater aquifers.
This situation was especially hard to comprehend given that California has in the last 15 years lead the rest of the USA it its relatively tough attitude to atmospheric emissions from industry and transport (and in gun control for that matter, especially as far as assault rifles are concerned).
Well (excuse the pun), California has finally realised it has a serious problem, in fact a crisis, with its groundwater supply, both in terms of quantity and quality. It recently passed into law a Groundwater Act, which covers management of the 120 biggest aquifers in the State. The Act passes control of these to local authorities (vis a vis our Regional Councils), but reserves the right for the State to take over if things turn to custard. In fact, similar to what happened with Environment Canterbury a few years ago, when the government appointed temporary Commissioners.
An interesting point of difference between New Zealand and California is that while our groundwater aquifers drain slowly into the sea, being more-or-less constantly recharged by rainfall and river flow, California’s are almost all fully contained. If we used too much of ours for a period, reducing off-take will allow them to recharge relatively quickly. However, the rate of recharge of California’s aquifers is miniscule by comparison. Water-users have been extracting ever-increasing volumes of water for agriculture, industry and residential use, and now the water-tables are dropping rapidly.
Many of the large aquifers in California are now so drawn down due to increasing withdrawals and lack of recharge from successive drought years that most experts doubt that they will ever become fully recharged again. On top of this, virtually the only recharge that is occurring is drainage from agriculture, which contains nitrate and other undesirable chemicals. These have an increasingly adverse effect on the quality of the remaining groundwater.
So the race is now on to learn how best to manage both the quantity and quality of these aquifers, before it is too late. Many Californian hydrologists, agriculturalists and water-managers have visited Israel, perhaps the leading country in water-use efficiency. Heavy restrictions are starting to be applied on water use. In agriculture, a big obstacle to water efficiency is the low water-holding capacity of the predominantly sandy soils. In horticulture and some cropping, it is cost-effective to install high-efficiency drip-irrigation systems, where each plant is being delivered exactly the amount of water it needs, and no more, on a daily basis.
However, this technology is not viable for broadacre crops and pastures cut and carried for indoor feeding of animals. Restrictions on water are leading to ever-increasing numbers of Californian farmers, in particular dairy farmers, shifting to other States, particularly Idaho. An equally big problem faced by dairy farmers is the land application of manure from cow and cattle houses. Not just nitrate but even organic nitrogen gets leached into the groundwater because of the highly porous soils. And if that’s not enough, there are the high gaseous emissions of ammonia as well. Moreover, while agriculture has intensified in the vicinity of the biggest aquifers, the State’s population has increased most rapidly far away from the sources of water, requiring expensive and efficiency-sapping water transfer.
So California is up for some very difficult decisions in the years ahead. Proposals to pipe water over the Rockies – akin to bringing some of the excess West Coast rainfall over the Southern Alps to Canterbury – are mind-numbingly expensive, and almost certainly more expensive than installing desalinisation plants near Los Angeles and San Francisco. Much investigation is going into how and where to store rainfall run-off water and/or how to feed it into the most porous aquifers. In comparison, management of New Zealand’s water supply and quality – with Canterbury and the Rotorua Lakes areas being the most difficult areas – does not face anything like the same stark challenges as California’s, but it does require all of us to understand and respect the perspectives of all water-user groups to achieve optimum outcomes.
All kiwis benefit from the standard of living that our country’s huge agricultural exports bring. However, it is simply not acceptable to have streams, rivers and lakes that are not safe for appropriate recreational use, and groundwater that is not safe to drink. Fully 75% of the rain that falls on New Zealand flows out to sea eventually, providing a constant flushing effect on our waterways, lakes and groundwater. It is up to all of us to ensure that the amount of water present on the land at any one time stays acceptably pure while it is in transit. This requires both short and long-term thinking; water leached from agricultural land, and the nitrate in it, can take from less than a day to 80 years or more to reach the catchment lake, depending on location!
The dairy industry has taken the lion’s share of the blame for the deterioration in water quality, particularly in Canterbury and central North Island lake catchments. However much has been learnt and put into practice over the past decade, including fencing off waterways to prevent direct stock entry, better dairy shed effluent management, the use of riparian strips, and much more efficient irrigation technology on the 23% of New Zealand’s dairying that is irrigated.
The main problem still faced in New Zealand is the cow urine patch – the source of the majority of both the nitrate leached from the soil, and the nitrous oxide greenhouse gas (GHG) emitted to the atmosphere. The reason for this is that far too much nitrogen (N) is deposited in the urine patch for the pasture to be able to recover as it is being converted from urine-urea to nitrate in the soil. Much of the excess ends up being leached through the soil as nitrate.
One potential solution that was being touted when milk payouts were high was to house cows year-round, so that excreta can be collected and spread evenly over the whole farm. However, as well as being a long way from what kiwis identify as our ‘brand NZ’, cow housing has now been proven to simply swop one environmental problem (nitrate leaching) for another – emission of ammonia gas. Ammonia is volatilised from the houses themselves, from the manure and effluent during storage prior to spreading, and during the spreading operation itself.
The attitude in countries that rely on cow housing used to be that ‘Ammonia emissions don’t matter – it is not a global warming gas’. Maybe not, but it is now recognised as the causative agent in the fine particle smog that is so deadly to our respiratory systems. Ammonia gas attracts to it nitric, sulphuric and carbonic acid nuclei derived from industrial pollution to form these tiny (<2.5 nanometer) particles. As a result. More and more countries now require effluent plowed under or injected into the subsoil – a very expensive operation either way.
Another longer-term solution under investigation for New Zealand is the breeding of pasture and forage plants that contain lower protein levels, that better match dietary requirements, meaning there is less excess N being voided in the urine. The big challenge to overcome in this plant breeding is to ensure that yields and therefore farm production and profitability do not suffer. There is scope for genetically-modified grasses to achieve this, but again is that what kiwis want for ‘brand NZ’?
Other practices such as planting different species on different topographies and the use of stand-off pads to reduce the amount of time cows spend on the pasture can provide some benefit, but add additional management costs and require additional skills. Improved irrigation efficiency is a big help in drier areas, but nitrate still gets leached in the wetter months or in unseasonal rainfall events.
So my money (literally) is on a combination of two new technologies I have been involved in developing. Both of these can easily be incorporated into dairy farming as practised in New Zealand, with little additional time input and a net increase in farm profitability.
The first is the one I mentioned at the start – the Spikey® urine patch detection and treatment. Spikey® is a tow-behind or tractor-mounted device that is run over recently-grazed pasture daily or every second day – ie, on a ‘follow-the-cows’ basis. It detects the fresh urine patches by measuring soil electrical conductivity and simultaneously treats them with ORUN® spray. ORUN® contains tiny amounts of the totally safe urease inhibitor nbpt (the same product used on SustaiN and N-Protect granular urea). This keeps the urine-urea present in that form for a few days (before breaking down to plant-available P and N), enabling it to spread laterally by itself. This spreading creates an average 70% increase in the size of urine patches. This in turn increases pasture production, by 5-10% overall by our estimates, and reduces both nitrate leaching and GHG emissions. The addition of the growth promotant gibberellic acid to ORUN® further improves the response.
This increase in pasture production easily covers the entire costs of the use of Spikey®. After
very successful trialling of the Spikey® pre-production prototype funded by the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC), the first farm-scale versions are being built. Various research organisations are comparing the effectiveness of various alternative sprays, to see if anything is superior to ORUN®.
An automatic spin-off from utilising more of the urine-N by increasing the size of the urine-patches is that less input of fertiliser N is needed to maintain any given level of farm production. There is no magic in this; it is simply a result of ‘tightening the N cycle’, akin to repairing cracks in a swimming pool so that it doesn’t need to be topped up so often.
Reducing N inputs even further is the specific objective of the second technology, called ONEsystem®. The system uses wetted prilled urea treated with the same inhibitor nbpt used on improved granular urea products SustaiN and N-Protect, but it achieves a further 50% or more improvement in effectiveness; meaning an average doubling in effectiveness compared to granular urea. One of the key reasons for this is the vastly better coverage achieved. ONEsystem® delivers 10 particles per unit area for every one of granular urea. These much smaller prills provide a far more consistent supply of N to each pasture plant. And, unlike urea solution (urea dissolved in water), the N in ONEsystem® is not susceptible to the ammonia volatilisation losses which limit the effectiveness of urea solutions.
Furthermore, unlike other non-granular ureas, the preparation and application of ONEsystem® requires no pre-handling or highly specialised equipment. It just needs spinning discs capable of accurately spreading the much reduced N application rates that are needed to achieve the same yields, and a simple spray system to wet the prills with nbpt solution during spreading.
Farm-scale trials using both technologies are planned for this spring. Reductions of 50% in both nitrate leaching and fertiliser N inputs at current levels of production are anticipated where the two technologies are used together. Both operations will be able to be done in the same pass.
I have been very proud, and humbled at the same time, to be told by many farmers over the years that my efforts in bringing products like RPR and SustaiN to the market, and making a stand on issues such as superphoshate quality, phosphorus run-off, cadmium levels in superphosphate, and nitrate leaching are widely respected. The Spikey® and ONEsystem® technologies are simply the latest developments in my ongoing endeavours to keep improving farm profitability while protecting the environment. I hope I have learnt to be a bit more patient!
From my mainly soil fertility scientist’s perspective, the keys are to
(i) grow nutritious pasture as cost-effectively as possible; encourage clover,
(ii) do whatever you can to get the utilisation of the pasture as high as possible,
(iii) minimise bought-in feed,
(iv) do whatever you can to increase the utilisation of the nutrients in urine, dung and dairy-shed effluent.
(i) Growing nutritious pasture cheaply. If you have reasonably good soil tests already, as most dairy farmers do, you can cut back dramatically on superphosphate – by half or more, or even stopped if Olsen P levels are over 40- for the next 2 years. Potash (K) and sulphur (S) needs to be applied more regularly than P, but rates can be reduced. The most important nutrient to manage well is nitrogen (N). How you do this depends a lot on your soil organic matter status. If you have a soil rich in organic matter, you will not get as big a response to N, so restrict N applications to when you really need to reach a higher feed wedge. Use SustaiN or N-Protect instead of ordinary urea – it really is worth the extra $40-50/tonne. Our ‘ONEsystem’ wetted, nbpt-treated prilled urea is far more efficient again, but only just starting to become available. For N-hungry farms with low pasture N levels (new conversions and most irrigated farms, especially on shallow soils), follow the cows with 20-25 kg N/ha of SustaiN, N-Protect or ONEsystem; limit annual use to no more than 180 kg N/ha.
(ii) Optimising pasture utilisation. You must put the effort into monitoring your pasture production weekly on every paddock and recording this, and monitoring your post-grazing residuals. Leaving the optimum pasture level (typically 1500-1700 kgDM/ha) in every paddock – not more, not less – is vital to gaining optimum DM before the next rotation. If the paddock still has 2000 kg DM when the cows come out for milking, put them back for a few hours afterwards; don’t just put them into a new paddock. It really is worth the effort. Ideally, use a computerised grazing management tool like the LIC ‘Minda’ program. Within a few rotations, you will start to see which are your best and worst paddocks. You can assess whether the poorer ones need resowng, or whether they just need more N than the others. Get advice on optimum modern pest-resistant clovers to have in the mix.
(iii) Minimise bought-in feed. Growing and utilising more grass is always the cheapest way to produce more milk. Alternative forages and bought in feed should only be a means to get over seasonal climatic difficulties and soil limitations eg pugging in winter. As your pasture utilisation improves, more paddocks can be set aside for silage. Try to minimise wastage during feeding out supplements. Check comparative costs and ME content of alternative feeds where they have to be used.
(iv) Optimise the use of nutrients in urine, dung and effluent. Typically, 40-70% of the N in urine is wasted. New technology being developed by Pastoral Robotics Ltd (Spikey) greatly enhances the recovery of the N in urine by the pasture, reducing nitrate leaching in the process. In the meantime, avoid excess N levels in pasture (which leads to higher N content in the urine) by putting N on in small applications, within 3 days of grazing. If dung pats are drying out and not breaking down, you should be introducing the deep-burrowing earthworm (A.longa) and dung-beetles if available. Get effluent on to every possible paddock possible, as low a rate as possible, within the limitations of available equipment and farm layout and topography.
As with any commodity, prices go up and down. With increasing intensification, increased use of bought-in feed and heavy N use, NZ costs of dairy production were increasing towards those of our competitors. However, we have the ability to reduce costs and get through the current low prices more easily than our competitors. Just hang in there.
PRESS RELEASE February 29 2016
Pastoral Robotics Ltd, founded by Aucklanders Geoff Bates and Bert Quin, has received a grant from the New Zealand Agricultural Greenhouse Gas Research Council (NZAGRC) to help optimisation and on-farm testing of its full-size ‘Spikey’ prototype. Spikey® is a tow-behind device for dairy farmers to detect and treat fresh cow urine patches, long before they become visible via increased grass growth. “By the time they are visible, it is too late to do anything much about reducing either losses of greenhouse gases such as nitrous oxide, or nitrate leaching”, says Dr Quin.
Geoff Bates said that Spikey® essentially measures soil electrical conductivity to allow detection of fresh urine patches on a daily or every-second-day basis, and simultaneously treat them with the most appropriate spray treatment for the farm’s location and soil type. The first product developed, named ORUN®, is a mix of the urease inhibitor nbot and the growth promotant gibberellic acid. Field tests to date show an average 70% increase in nitrogen (N) recovery from the urine patch. The ORUN® keeps the urea in the urine in that form for a few days, allowing the urea to spread out so that more plants access the nitrogen . This results in more grass growth from every urine patch, and lower N losses.
“Calculations indicate that up to 14% more grass can be grown annually” said Quin. “ The main environmental benefit to date has been less nitrate in the soil profile. We are now investigating new formulations and additions to ORUN® that will minimise nitrous oxide greenhouse gas emissions in as wide a range of conditions as possible.
The pair say that unlike most other ways of reducing losses to the environment under investigation, Spikey® is a win-win solution for farmers in that the extra grass growth obtained makes it very cost-effective for farmers to use in its own right. Towing Spikey® over the 3-4 hectares grazed each day would take only 20-30 minutes, they say. “On top of this, it will also be possible to apply fertiliser nitrogen at the same time, so for farmers ‘following the cows’ with fertiliser urea anyway, the increase in time required would be minimal.”
Pastoral Robotics expects to have an 8-meter width ‘Spikey2’ ready for farm trials in late March.
Dr Long Nguyen, partner of Dr Bert Quin in international consultancy company Group ONE Consultancy, returned from a visit to China on 25th October. During his visit, Dr Nguyen had the opportunity to advance discussions regarding research collaboration with Chief Professor Yong Li of the Chinese Academy of Agricultural Sciences (CAAS) in Beijing. Professor Li had visited Group ONE Consultancy for initial discussions earlier this year (see earlier post and photo). Plans are now well underway for collaborative research projects to commence in 2016. More details from Dr Nguyen’s visit will be posted soon.
Dr Bert Quin presents data on Spikey® urine detection and treatment and ONEsystem® nbpt-treated prilled urea to the international conference on Land Use and Water Quality (LuWQ) in Vienna, September 2015
Researchers from 40 countries attended this 2-yearly conference, including a significant contingent from several regional councils and Lincoln Agritech from New Zealand. The 2015 conference focused very much on nitrate leaching from agricultural systems. Dr Quin said he was struck by how much ‘big-system’ measuring and modelling was being done on nitrate levels in waterbodies in Europe, but how little innovative developments that farmers could easily adopt to reduce nitrate leaching were coming forward, despite huge taxpayer-funded research. “There seems an even bigger disconnect between research and farmers in most European countries than there is in NZ”, he said. The biggest exception is Ireland, where scientists still get ‘down-and-dirty’ on farms.