Hello and welcome to the Stuttgart Online Field Day.
My name is Trent Roberts.
I'm a soil fertility extension specialist
with the University of Arkansas System Division of Agriculture.
And today we're going to be talking about nutrient management and rice.
So this year has proved to present us with many, many challenges.
One issue that we've seen a lot is different
disease, nutrient symptomology.
That's been hard to really pinpoint and identify what is going on.
And so what I want to talk about today are some tools that we can use
to hopefully help us narrow down and determine
the maladies that we're seeing in rice and try to come up with
some corrective measures.
And so tissue testing or tissue sampling can be a great tool
that producers can use to help identify nutrient related issues.
There are really two categories the tissue testing is going to fall into.
It can be reactive or it can be proactive.
And so when we think about those two distinctly different approaches,
I want to cover each of them individually.
But first, I want to talk about just how to take a proper tissue sample.
And so when we think about Rice in particular, there are two,
we'll say distinctly different time periods in the rice
growing season where we're going to sample different portions of the plant.
So typically, if we're early in the growth season prior to flooding
or somewhere up to around green ring or the beginning of reproductive growth,
we're typically going to encourage producers and consultants
to sample the entire rice plant.
And part of the reason for that
is early in the season, there's just not enough biomass.
The rice plant isn't large enough to gauge
the nutrient sufficiency from a single leaf.
Once we pass that green ring
growth stage and we start to get into the reproductive growth stages,
then we recommend taking the uppermost colored leaf on the rice plant.
So those are kind of the two separate plant parts
that we want to sample dependent on the rice growth stage.
Now, the next thing you need to take into consideration is once
you have those plant parts, what should you do with them?
And what I would recommend is one of the most important things
is to carry some paper bags with you.
And so if you think about proper handling of these samples,
we actually want to try to get them as dry as we can, as quick as we can.
And so, you know, what I try to tell people is if you're grabbing tissue
samples, rice or any crop, you know, have some paper bags at your disposal.
Grab those leaves or grab those plant parts, put them in a paper bag
and toss them on the windshield of your pickup truck
because they're going to start drying and that's going to aid in.
We'll just say the storage of those samples prior to analysis.
So just to give you an idea, as soon as we receive
them at the diagnostic lab, they're going to go straight in the oven.
So any drying that you're able to accomplish in the transport
of those samples is going to be very beneficial.
Now, one thing I do want to point out
is, depending on what you're trying to diagnose,
you may have to send in different types of tissue samples and different methods.
But I really want to emphasize that if you're interested in diagnosing
nutrient related issues, we want those samples in paper sacks.
And we want them as dry as possible
because we're going to put them in the oven when we get them.
And, you know, any moisture or wet storage
and transport can actually be negative for those tissue samples.
So the next thing is,
let's talk about this proactive versus reactive type of sampling.
So historically, we've always implemented reactive sampling.
And what I mean by that is we see a malady or we see a problem in the field,
and then we try to go out after the fact and determine, you know, what
that issue is, identify the problem, and then come up with corrective measures.
You know, traditionally we've done this
because we don't have tools to be proactive in our nutrient management.
So in some situations this year, we had rice.
That wasn't the right color.
We had rice that wasn't the right height.
And so we had a reactive approach where we went out, we took leaf samples,
we looked at tissue sufficiency levels and then determine
when and where to apply nutrients to correct those issues.
One thing that you need to keep in mind, especially with reactive management,
is that there's a finite time frame or window for specific nutrients
that we need to get them out in order to be effective.
And that's going to be very different
for the different plan, essential elements for rice.
You know, typically with something like zinc,
we need to get those issues addressed very early in the season
in order to recover or maximize our yield potential
with other elements, such as nitrogen and potash.
You know, as long as we have adequate amounts early in the season,
we can make rescue applications very late
in the season and still produce near maximal yield.
So you need to understand
that interaction of timing of application and the different nutrients.
When we're thinking about reactive management, some of the things
that we saw this year with some unexplained occurrences
had to do a lot with rooting issues.
And some of those were directly
tied to compaction, which is probably associated with tillage
that was completed during very wet time periods.
And so that's one thing that we saw is very obvious nutrient
deficiency symptoms in tire tracks or tillage passes.
That essentially was a compaction issue
that related all the way back to when that tillage was completed
and the soil was was really too wet to be worked.
So keep in mind that in some times when you think you're making progress
and getting things done early,
how that can potentially affect your downstream management.
And really in that particular situation that reduce rooting with the compaction
led to issues with nitrogen and sulfur uptake, which required
an in-season corrective application that was fairly costly.
So just keep those things in mind.
Now, I'm going to shift gears to proactive nutrient management.
So over the past few years, you've heard our group talk a lot about tissue sampling
for diagnosing hidden hunger
and trying to stay ahead of potential nutrient deficiency symptoms.
And one thing that we have now in Rice is
we have a tool for pre plant fertilizer analysis.
We have the economic potash rate calculator.
But we've also developed an in-season tool that allows us to tissue test
the y leaf or the uppermost colored leaf of a rice plant
to determine if potash is sufficient in that plant to produce maximal yield.
So similar to what we've discussed in soybean, this is a curve
or a tissue concentration that's going to be dynamic and change over time.
And so as we start about the PPI or R1 growth stage
and we move throughout the season and that plant grows,
there are going to be some slight changes in how we interpret
that sufficient level of potash in the plant.
But the idea being that this is a proactive approach
to managing potash in our rice fields.
What we can do is starting at our one grow stage, take those
uppermost collard leaves and submit them for analysis.
And based on the results that we get back, determine
if potash is sufficient in those particular fields.
Now, why is this important?
Well, in my experience, we typically start to see potash deficiency after.
Right, that green ring or half inch growth stage.
So a lot of times we apply a very large rate of pre flood, nitrogen.
The plant starts to grow very rapidly.
We put on a lot of biomass in a very short time period.
And so we really start to see those potash deficiency symptoms occur,
you know, somewhere around that three to four week time
frame after pre flood nitrogen application.
What this tool allows us to do
is potentially identify and correct those potash deficiencies
before the visual potash deficiency symptoms ever occur.
You know, one struggle with potash visual deficiency symptoms
is sometimes with rice, with a very small or narrow leaf blade.
It's hard to determine if that symptomology has to do with potash
or if it's just natural leaf senescence due to those lower older leaves,
you know, being down in the canopy and shaded from the sunlight.
But whether you're looking at using reactive or proactive tissue sampling,
you know, please understand that as a producer,
there are a lot of tools at your disposal to help ensure
the nutrients are not limiting your rice production system.
And so always feel free
to reach out with any questions or concerns that you might have.
We always appreciate the support of the station staff here
that helps keep our plots up and the Rice Research and Promotion Board
for the support to continue this research that helps Arkansas farmers. Thank you.