‘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!
It was good to see an admission from Ravensdown CEO Greg Campbell on Stuff a few days ago (Gerard Hutching, Feb 05) that too much nitrogen fertiliser is being used on many farms, and that more efficient products are needed and under development. Credit where credit is due. Take note Doug Edmeades. It will be interesting to see the cost premium put on these. Meanwhile, ONEsystem (wetted, urease-inhibitor treated prilled urea, twice as efficient as granular urea in Canterbury trials), is already here, greatly reducing environmental losses and farmer N requirements and REDUCING COSTS at the same time. What’s not to like? It would be good to discuss options for the the wider uptake of this technology with Ravensdown. I’ll bet a Speights or 3 that ONEsystem will beat any product they are developing hands down on cost-effectiveness to the farmer and on environmental benefits. I always said when I developed SustaiN in 2002 (rubbished for 10 years by the industry and now Ballance’s biggest-selling N fert by far, forcing Greg’s bunch to follow with copycat N-Protect), that it was a good start, but only a start. ONEsystem is the end-game. Trust me.
Rich McDowell used to be very precise and no-nonsense with scientific facts and cause and effect before he became a sort of unofficial roving ambassador for the superphosphate industry a few years ago. Now, outside of peat soils, the form of P fertiliser used apparently doesn’t matter. The fact that the average concentrations of filterable reactive phosphorus (ie dissolved P, more or less) at testing sites over the period 1994-2013 has decreased on more sites than have increased is implied to be a major achievement (interview of Rich by Tim Fulton, Farmers Weekly online, 5 Feb). To me, this is nonsense. Firstly, where is the data on the actual changes in concentrations? Is the mean and average up or down or sideways? Etc, etc. Certainly, fencing off waterways, riperian strips, planting susceptible areas in native bush have helped reduce P run-off. But as Rich knows, the single biggest improvement by far will be made by changing from soluble P to RPR, at no cost – in fact a saving – to the farmer. It is misleading to say “The work found little evidence the improvement was caused by a ‘change to’ low water-soluble phosphorus fertilisers”. What forms of ‘low-soluble P’? How many monitoring sites? How many years?
New Quinfert Field Advisor Brittany Stratton is based in the Manawatu/Whanganui area. Brittany completed a degree in Agricultural Science at Massey University and is keen to help farmers optimize their farm production with fertiliser products that minimise adverse effects on the environment.
RPR Revisited 5:
The Sources and Causes of Soil P Losses and the Role of RPR in Reducing Them
1Bert F. Quin and 2Gordon Rajendram
1Quin Environmentals (NZ) Ltd
2Eurofins NZ Ltd
Presented to the
New Zealand Soil Science Society Conference
Napier, New Zealand, 3-6 Dec 2018
Figure 1: The mechanisms for the gradual saturation of soil solution P sorption capacity
RG McLaren, KC Cameron: Soil Science, 1990, pg 211-212
PR or ASC – what’s in a name?
PR vs ASC – What’s in a name (cont’d)
The goal; a dual-purpose soil agronomic and environmental management test
DRP = 0.069 (Olsen P/PR) + 0.007
Relevance to RPR
Figure 5. P concentrations in surface runoff: Water soluble P versus non water soluble P