http://www.courtyard-partnership.co.uk/
http://www.soilquest.co.uk/
http://www.soyl.com/
Any others I have missed other than DIY?
http://www.soilquest.co.uk/
http://www.soyl.com/
Any others I have missed other than DIY?
Variable rate drilling
- Thread starter farmerfred86
- Start date
- Location
- Ashbourne, Derbyshire
Thats not quite how the sampling works,
Yes there is a sample taken from every hectare, but it is made up from 20 or so other sub-samples from within that hectare.
I've said it before, when we first started using it the saving were huge, it paid for the sampling, the GPS box and the extra to go to a VR ready spreader
How accurate the sub sampling is depends on the dilligence of the sampler. I caught one with a spade right beside his quad bike not doing the sub sampling at all, just filling the bag with one sample only. I had been watching him do this on a number of occasions. He was thrown out & that firm had to resample the fields this individual had messed up.
Junk information in, junk information out!
Rob - How did you quantify your saving? Product saved vs blanket doses?
- Location
- Ashbourne, Derbyshire
Yes
- Location
- Ashbourne, Derbyshire
Maybe i'm getting seduced by the sales hype but i think the whole principle of VR inputs is sound.
We only do VR P+K at the moment but i really want to move onto VR N and seed.
There has has to be an element of inaccuracy in everything that we have to accept, like @Clive said, for a true VR N calculation you'll have to do a live tissue test on EVERY plant and for the correct another of N onto that plant to be truly VR, there has to be some averaging done.
We only do VR P+K at the moment but i really want to move onto VR N and seed.
There has has to be an element of inaccuracy in everything that we have to accept, like @Clive said, for a true VR N calculation you'll have to do a live tissue test on EVERY plant and for the correct another of N onto that plant to be truly VR, there has to be some averaging done.
Savings are easy - if I apply no N this year I will save a load of money - they doesn't make it the right thing to do though
Composite samples are worse than single ones as that are not actually a sample if any point in the field
Zoning is the best way if you want to vra IMO but even that is limited by resolution and the pretty contor maps are no more than a mathematical equation
Last edited:
I'm wandering off topic here, but I am less convinced by VR N & seed. I have trialled 3 blocks of fields vs the fields next door & don't often see a yield increase. VR seed & N has much better canopy & more even ear numbers so there is a non-cash benefit in crop consistency and probably less lodging but until the average yield per field rises above extra input cost & the not inconsiderable hassle with shape files, hardware issues etc I'm pretty ambivalent. I have had 3 springs where it has been too dry/wet/cold/N doses too close together etc to see the response. I have been trialling this for 3 years so perhaps one day we will get one of these mythical consitent growing seasons where I get my positive margin over input cost.
I'm still trialling VR N & seed but am happy that VR PKMg is giving positive payback.
Composite samples give an average for that ha grid section. It's back to how much detail you require, what the extra sampling costs & how precise your spreaders/sprayers/drills can apply the different rates.
Zoning based on conductivity scans every 24m backed up by ground truthing & historical yield/canopy maps is better than the basic 1 ha grid system IMO.
Steevo
Member
- Location
- Gloucestershire
Kinsey seemed to think EC Veris scanning had a part to play. Though he did have an interest in a scanning company IIRC.
I don't like the idea of mixing samples - you need point samples to look at what you have
zoning is an improvement on the grid method but all are flawed by the gross over simplification of the model they base application upon - non are looking at nutrient ratios and just apply to maintain or correct indices - 21st century application methods based on 100 year old soil nutrition models !
VRA application of base nutrition focuses on P, K Mg and Ph - CA/Mg ratios would be a better starting point in most cases. I was advised on the basis of grid samples year ago to apply VRA lime (calcium) - I know know that some of those fields were too high in Ca and lime was the last thing they needed - ph is not a measure of Ca its a measure of H in the sample !
............the entire concept of PF is oversimplified to make it both possible and therefore a saleable product, look closer and its no better than your grandfather
I maintain a proper single sample per field will tell you more than many basic ones and set you on the right road to fixing nutrient ratios and be a lot cheaper to implement
N sensing is another thing that most who use it don't really understand IMO as well ! it measures chlorophyll content of plants NOT nitrogen levels but varies N rates based on information it collects - there are many reasons why chlorophyll content varies between plants with just one of them being N levels ..................again a gross over simplification of something much more complex but with a liberal sprinkling of great marketing !
all that said there are ways to use the tech in a useful way ! use yield maps to replace P& K off take for example to ensure you maintain levels once you know they are correct. I like what I have seen and done with EC scanning so far - I think it might help targeted samples (full samples) to maybe break filed down into zones that then with a good application model might be a better way forward
I have been using various PF and VRA for over 10 years now - as I said I think its a very interesting area and these things have to start somewhere but i'm not going to kid myself it saves or makes me a penny extra (yet ) ! The technology works just fine, the agronomy behind the models sucks though frankly in most cases !
- Location
- Ashbourne, Derbyshire
But surely there are more variables to yield than P and K
many, but your typical VRA nutrition package focuses very much on PK mg and pH .............and only looks at correcting deficiencies of them, no regard to ratios or laws of maximum etc
over simplified and in some cases misleading in the wrong direction that could make things worse not better, its important to remember not every input improves things, some can make a situation worse like being advised to spread calcium carbonate lime based on a low Ph result when your Ca / Mg ratio is already Ca biased
What do you define as a proper sample? Albrecht?
yes, certainly more than P,K,Mg and ph anyway
We have identified variable seed rates as the biggest contributor to yield improvement of any variable input. Feedback from farmers supports this and they report more even crops, improved performance in poorer areas and higher overall yields.
From analysing the data set we hold for over 500 Rhiza farmers, we found that between 2010 and 2012 farmers using variable seed rates achieved an average WW yield improvement of 13% compared to Rhiza farmers using a standard flat rate (see below).
To ensure as many farmers as possible are reaping the benefits of variable rate seed, Rhiza will be running a series of free summer workshops.
Workshops will focus on the benefits of variable seed rates, current advice and best practice on what rates to use, and how farmers can implement this through the Rhiza Toolbox. We will also be discussing establishment methods along with cover crops and green manuring. All information will be backed up by practical examples and Rhiza farmer case studies.
Dates confirmed so far:
Thursday 26th June - Deanwood Park Golf Club, Stockcross, Newbury, RG20 8JP
Tuesday 1st July - Marlborough Golf Club, The Common, Marlborough, SN8 1DU
Workshops will run from 9:00 until 12:00 when lunch will be provided.
More dates and venues to be announced soon.
Please PM me to reserve your place.
Workshops will focus on the benefits of variable seed rates, current advice and best practice on what rates to use, and how farmers can implement this through the Rhiza Toolbox. We will also be discussing establishment methods along with cover crops and green manuring. All information will be backed up by practical examples and Rhiza farmer case studies.
Dates confirmed so far:
Thursday 26th June - Deanwood Park Golf Club, Stockcross, Newbury, RG20 8JP
Tuesday 1st July - Marlborough Golf Club, The Common, Marlborough, SN8 1DU
Workshops will run from 9:00 until 12:00 when lunch will be provided.
More dates and venues to be announced soon.
Please PM me to reserve your place.
- Location
- East yorks
How many rates we're used in your example?
The results come from looking at the aggregated yield data of Rhiza farmers using VRA seed compared to Rhiza farmers who are not. The farmers are in control of what rates they use and as we work with farmers all over the UK, these will vary considerably depending on location and soil types.
We normally recommend a minimum of 30% variation between minimum and maximum rate but again this depends on the level of variation within a field and in some cases farmers are using over 100% variation between zones.
We have not looked at grain quality, just yield. In the WW yield maps above the farmer cut back the seed rate in the deep valley running through the middle of the field where lodging had been a problem and increased rates on the shallow, stony bank to the west of the field where poor establishment had been an issue.
The combination of reduced lodging and an increase in productivity in the poorer performing area within the field resulted in overall higher yield.