13 - 2020 Soybean Management Field Days - Soybean Planting Date – Yield
Soybean Planting Date - Yield - Jim Specht, UNL Emeritus Professor of Agronomy and Horticulture covers the following: What is the relationship between soybean yield and planting date? On average, delaying planting after May 1 results in a yield reduction of about 0.5 bushels per acre per day! Let’s look at the data.
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[00:00:07.730]Okay, my name is Jim Specht,
[00:00:09.620]a Professor in Agronomy, now retired
[00:00:12.120]at the University of Nebraska,
[00:00:13.620]and my specialty was Soybean Physiology and Production
[00:00:18.150]in addition to Genetics Genomics,
[00:00:20.080]but today we're gonna focus on physiology
[00:00:22.270]in production of soybeans.
[00:00:24.270]And, what we're gonna do is discuss yield-increasing
[00:00:27.040]soybean production practices that we did not know about
[00:00:30.610]in the past, and then we're gonna talk about the impact
[00:00:33.250]of a cover crop when it's inserted into,
[00:00:35.430]say a corn-soybean rotation,
[00:00:37.580]the impact that cover crop will have.
[00:00:40.600]Okay, so the first thing we're talking about today
[00:00:42.740]is, we have six items on the list,
[00:00:44.720]the last one will be covered by Steve Melvin,
[00:00:48.440]and, he will go to his slide set for that.
[00:00:52.510]But we're gonna talk about advancing your planting date
[00:00:55.000]towards late April, early May,
[00:00:56.810]as a good way to increase your soybean yield.
[00:01:00.510]So let's talk about that.
[00:01:03.090]Here you see on this slide are two pictures,
[00:01:06.030]one taken in 2003, one taken in 2004
[00:01:09.340]just after the summer solstice
[00:01:11.320]which is the longest day of the year,
[00:01:12.840]which is June 21st in most years.
[00:01:16.910]You can see some plot signs there indicating
[00:01:20.157]late April mid May, late May and mid June planting dates.
[00:01:26.990]You can see the color change from green to brown there
[00:01:29.940]as we delay soybean planting.
[00:01:32.590]You also know that I put in red, blue, green
[00:01:36.360]and brown lines there because I'm gonna use those colors
[00:01:39.070]when I describe the data that comes off of planting dates
[00:01:42.430]that are made on those dates.
[00:01:44.370]We'll talk about the items at the bottom slides
[00:01:47.340]down to the slide, where we'll talk about the items
[00:01:50.190]at the bottom of each picture coming up here
[00:01:53.270]and we'll deal with those issues then.
[00:01:57.080]Now, get right to the bottom line,
[00:01:58.760]this work was done back in 2003 and four
[00:02:01.540]showed that there's a definite advantage
[00:02:03.840]of early soybean with yields.
[00:02:06.370]So we have seen yield on the left axis
[00:02:08.900]and the planting date on the bottom axis.
[00:02:10.920]And here on the top of the chart,
[00:02:12.810]you can see the actual monthly days.
[00:02:15.460]What you see there is the red line
[00:02:17.190]representing the late April early May planting date
[00:02:21.500]all the way down to the brown line that was shown
[00:02:23.760]on the prior picture slide.
[00:02:25.960]And what you see here is that soybean yield declines
[00:02:30.260]as you plant it later in the season.
[00:02:32.789]And you can see at the top part of the slide,
[00:02:35.600]it was about five eighths of a bushel
[00:02:37.400]per acre per year for the 2004,
[00:02:41.250]and for 2003, it was a little bit less.
[00:02:44.780]And we'll talk about the reason for that later too.
[00:02:48.260]Now this has been confirmed in other studies.
[00:02:50.750]Dr. Patricia Grassini working also
[00:02:53.930]at the University of Nebraska,
[00:02:55.170]showing this applies both to the Southern Nebraska
[00:02:58.050]and Northern Nebraska and it applies more
[00:03:00.730]to irrigated fields than it does to rain fed fields
[00:03:03.430]because rain fed fields can be subject to August stress
[00:03:07.380]which reduces their response to early planting.
[00:03:11.520]So you can see on our left axis, you can see the yield
[00:03:13.960]on the bottom axis, the planting date.
[00:03:16.490]So it range from this case from a half a bushel
[00:03:18.880]to three quarters of a bushel per acre
[00:03:21.160]in different parts of Nebraska.
[00:03:23.460]The study has been examined also at the national level
[00:03:27.720]and at the north central region,
[00:03:30.030]Dr.Grassini and his colleague Shawn Conlin in Wisconsin,
[00:03:34.770]conducted a series of surveys and identified regions
[00:03:38.580]in each State that are very similar
[00:03:40.840]in climate, soil, and weather.
[00:03:43.150]And what they found there is when they take
[00:03:45.200]those individual regions which they called
[00:03:47.490]technology exploitation zones, and what they discovered
[00:03:51.790]was that planting date declines in all of those 10 regions,
[00:03:56.190]except perhaps for rain fed Nebraska.
[00:04:00.530]But if you look on the right side,
[00:04:02.020]you see they found the reason for that
[00:04:04.110]is there's ready response to early planting
[00:04:06.330]with irrigated fields because there was no not likely
[00:04:09.610]to be any water stress in August during the pod setting
[00:04:12.570]period which is from our three to our five.
[00:04:15.850]As you go left you have less water available
[00:04:18.830]during that pod setting period,
[00:04:22.026]and most dry land TEDs in Nebraska.
[00:04:26.340]And so if you even look down on a greater detailed scale
[00:04:29.480]on our sub TEDs in Nebraska,
[00:04:32.130]and someone elected those and sorted those
[00:04:34.130]into high yield and low class and high yield and low yield,
[00:04:38.330]thousands of each of those TEDs, what he found
[00:04:41.250]was that soybean planting was about seven days earlier
[00:04:45.150]in the high yield plots than it was in the low yield plots.
[00:04:49.080]So, if you wanna know more about this particular project,
[00:04:52.050]it's available online through CropWatch,
[00:04:54.260]you can go there and see.
[00:04:55.200]If you don't happen to be from Nebraska,
[00:04:57.170]you can go there and see the details there
[00:04:59.400]but if you happen to be in Nebraska you can see more detail.
[00:05:02.480]So, the planting date and soybean yield take-home points
[00:05:06.160]for this part of the presentation,
[00:05:08.090]is that there is a yield penalty
[00:05:10.010]for delaying soybean planting in Nebraska after May 1.
[00:05:13.890]It will generally average about 0.5 bushels per day,
[00:05:17.320]or about 3.5 bushels per acre, per week of delay.
[00:05:22.240]And it's greater in years when the yield potential
[00:05:24.750]is greater, that is to say where you don't have
[00:05:29.005]any water stress in August,
[00:05:32.184]and an irrigated field is always likely to respond
[00:05:33.077]better than a dry land field.
[00:05:33.910]So, take home point here is if you have both irrigated
[00:05:36.248]and dry land fields, plant your irrigated ones first.
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