Variable Rate Fert

[ado089]

Hi folks,
I've been doing variable rate on the
farm for a couple of years now with
pretty good results, $15-40/ac benefit.
As a result I've decided to take what
I've learnt and try to offer it to
others. The management zones I've been
creating are based on soil texture and
water flow modeling, essentially a water
orientated system matching nutrient
application with projected available
water. I guess I'm curious what others
are seeing from their VR work to get an
idea of what has been working and what
you feel are the downsides or pitfalls
or the system you are currently using.

[farmaholic]

ado: you the only one ding variable rate?

[craig]

I like your idea of trying to determine available water as an important part of the equation. I'm in a higher rainfall area and we are having issues on transition areas where extra moisture has seemed to give us a fertility boost. If we don't account for that we have lodging issues. If your in a drier area then your strategy might be entirely different. Have been in VR for probably 7 or 8 years and we continue to try to better understand the system and how to make it work better on our farm.

[gustgd]

What I learned from one year of VR fertilization. If
you spend a bunch of money on technology and
prescriptions, don't forget to account for weather.
Kill the weeds I they are present. Spray for
disease if conditions warrant. Watch for bugs.
Manage your rotation.
Timing is very important.
I guess what I'm trying to say is get your
agronomy perfect before investing in VR. It's a
later step not a starting place.

[SASKFARMER3]

gustd good point. We did variable rate
back in 1986 to 1992 in the dry years did
get some bonus but not worth the time.
Went back to old system of work the land
you have to the best of your ability
agronomy wise. Watch the weather and in
the end youll come out ahead. Its a end
point if you have every thing working on
your farm. Every thing.

[ado089]

SF3, you sound like you've been to an
agri-trend meeting or two. What I see
out there is guys putting on more inputs
than ever because their neighbor is,
their over priced agronomist tells them
to, their retailer tells them to, the
commercials tell them to, ect. all the
while the while yields stay the same or
maybe see small bumps. I use VR to push
yield without increasing cost and/or to
free up some costs to allocate that
$7/ac fert saving to a shot of Quilt and
copper or to kick in some releaf to give
those delicate canola seedlings a boost
through the flea beetles and rain.
Nutrient response curves are not linear
and alot of land is getting fertilized
beyond its economic benefit once we
start applying N beyond 90lbs/ac.

One example I have is a split field of
Canola, flat rate 90, VR avg rate of 67,
yield was identical, that savings
allowed me to use ESN for the same price
and gain 8bu/ac over the neighbor across
the fence who used the same fertility
program with NH3 planted the same day.

[saskcanfarmer]

Ado - What do you say to a guy like me?Inputs are there, fungy, up to date paralink drill, micros etc etc. Two years in a row we have set up half sections, different half sections. We had 8 reps on each. 4 with VR 4 with standard practices determined by soil tests and past expriences/field history. Both years the non VR strips OUTYIELDED the VR enough that it WASN'T ECONOMICAL to VR.

[ado089]

Was there variability there to start
with? Lodging? Maturity issues? Alot of
land it makes no sense to do it on at
this time. With that said, I've found
the weak part of most VR systems to be
the agronomist and not the maps or the
field. I match mine up with Western ag
labs PRS, I've found it to be
significantly better at indicating the
productive difference from zone to zone.
That aside if you are soil sampling at
all I think it makes alot of sense to
create some sort of zone maps to at
least ensure you are sampling from
locations that most represent the field.

[cropduster]

Interesting discussion here!!Variations in agronomy are a great quest. Anybody care to weigh in with info on the McCrae approach??Calcium/sulphate combos surface or seed applied. Seems like quite the rage in some parts of Ab. Don`t know if application based on variable soil maps or not. Good sales or reality????

[ado089]

Calcium sulfate, or gypsum is used as a
pH amendment, or a floculant to dislodge
phosphate from sodium. It has merit in
areas with photos extremes and most
certainly would be something that makes
sense as a VR application. To affect a
change application rates need to quite
high. Many areas in black soil and peat
region can have yield impacting pH
variations.

[bgmb]

ado, in our area the low areas and high spots could either be your lowest yield or highest yield depending on how much rain we get. So to me variable rate is pretty pointless unless you can predict how much rain we are going to get during the growing season. Variable rate for the most part is just another way for somebody to get your money.

I totally agree with gust and saskfarmer once everything else is perfect then start worrying about variable rate and even then over the long haul I don't think it will pay.

I am dead against hiring somebody to do the maps for you, if you are going to do the work yourself it might pay.

[ado089]

Okay I'm not trying to sell anyone on
here. I did make my own maps so the only
additional cost I have is two extra soil
samples per field, and I may not even do
that next year now that I have the
pattern figured out. It works great for
me but I also can't see across most of
my fields. That said I would suggest
that even in these wet years the hills
don't have the potential of the gently
sloped well drained areas and even in
ideal years the low spots have better
nutrient cycling requiring lower needs,
and they certainly need less if they are
under water. I'm definitely not saying
it is necessary or beneficial on all
acres or your farm but I do think it's
naive to ignore this technology. I'm
looking to explore why so many are
having a negative experience with VR
even though the theory is sound.

[TOM4CWB]

bgmb,

I believe you have hit the nail on the head.... MOISTURE/heat units/timing are the biggest variable factors for yeild on our dryland farm as well.

If there are bad soil patches... and headland issues... great to take care of these with VR is area is enough to justify. On irrigation land VR technology makes the most sense in the south where more heat units.

[craig]

We got into variable rate because we were throwing money away on our high organic soils. Too much fertility led to lodging and poor crops. Simple investing more and getting less. You could argue that soil tests are also a waste because you can't predict the weather for the coming season. Everyones situation is different. Just because it doesn't work for you doesn't mean it won't work for someone else. We are also building a knowledge base as we go. VR proved a failure many years ago because people went into it with preconceived ideas. We continue to learn and try to improve whatever system we use.

[mbratrud]

The past few years we have been Variable Rating as well.

We used Crop Pro consulting from Naicam to Veris our land, then we ground truthed and worked with them to develope 5 zones on our fields.

Each zone is then sampled by my wife and we use Western Ag Labs forecast model to write the perscription. This allows us to model water scenarios for each zone.

This year was the first year we really got to test it out (because we didn't flood) we definately seen a difference in the zones for N availabily from 10lbs available to over 60lbs available.

By having that knowledge we were able to vary our Fert and Seeding rates allowing us to acheive yield targets even out our maturity. At the end of the day saved about $30K on our farm without sacrificing yeild.

Every year is going to be different and just because we saved this year does not mean the same will be true in the future but its one more peice of information to make good decisions on including crop planning.

For example Guys that put soybeans on chemfallow had poorer yield results compared to stubble in our area and the theory is high N delayed nodulation. had they known that would they have changed field choices? On our farm we did.

Are soil analysis gosphel? No but its information and how you use it is important