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Beginning Soil Moisture 4-19-18

Here is an update on beginning soil moisture status. The left charts are as of 4/19/18 with the right charts being the previous week. You can click on the images to enlarge them. The ‘weekend moisture’ event I refer to was the blizzard 4/14/18.

Nebraska map

Bladen: The top foot is now slowly losing moisture one week later in spite of some weekend moisture. The second-fourth feet are all above 50% depletion.

Byron: Some weekend moisture may have allowed the top foot to remain steady.  The second and third feet are both over 50% depletion bringing the total soil moisture in the 1-4′ depths closer to 50% depletion. There must have been a soil crack along my PVC pipe to allow for the moisture spike you see in 3 and 4 feet and not 1 and 2 foot depths.


Clay Center: This is still the wettest location in spite of the top foot slowly drying out this week.  The second foot is still below field capacity with third and fourth feet and total soil moisture relatively unchanged. Must have had a soil crack along PVC pipe for third foot for the quick dip observed.


Lawrence Corn Stubble: Minimal change was observed at this location this past week.  Essentially all feet remained the same in regards to soil moisture.  A small crack along PVC pipe must have been present at 3 foot for short dip observed there.


Lawrence Soybean Stubble: This location (across road from corn stubble) showing dryer than last week. Top two feet now dryer than field capacity which increased the total (1-3′) soil moisture depletion.


Superior: Weekend moisture may have allowed the top foot to stay steady (as was also seen in Byron).  However, the second, third, and fourth feet all lost moisture leaving the total soil moisture (1-4′) above 35% depleted at this location.

JenREES 4-8-18

Reducing Soybean Seeding Rates:  Can I reduce soybean seeding rates and still maintain yield?  It’s a common question from soybean growers, especially those seeking to reduce input costs.  Every year during winter meetings I share what our growers have found.  We now have 11 years of On-Farm Research proven data.

The findings? Reducing soybean seeding rates from 180,000 or 150,000 seeds/acre to 120,000 seeds/acre doesn’t statistically reduce yields in 30- or 15-inch rows in silty clay loam and silt loam soils in south-central and eastern Nebraska. Results of 18 studies showed for seeding rates of 180K, 150K, and 120K seeds per acre, average yields were 69.0, 68.7, and 68.4 bu/ac, respectively (Figure 1). The early studies within this dataset all had seed germination of at least 90% listed on the seed bag. In all but two situations (seeded at 180,000 and achieving 88% germination), the growers were able to achieve 90% or greater of their planted stand.

Graph of yields from 18 soybean population studies

Figure 1. Yield results of on-farm seeding rate studies from 2006 to 2017 (15″ and 30″ rows). Average final stands: 90,000 = 83,067 plants per acre (ppa); 120,000 = 106,863 ppa; 150,000 = 132,700 ppa; and 180,000 = 157,924 ppa

 

 

 

 

 

 

 

 
As I share this data, I’ve often heard “but I seed higher rates because of X, Y, or Z…”; however, this dataset includes a lot of those reasons without negative yield consequences!  I’ve worked closely with these studies in walking the fields; taking notes and pics; counting plants, pods, and seeds; so I’m really confident of the research and the fact that soybeans truly compensate for reduced populations!  Outside of this research, I’ve also observed this in many soybean hail, crusting, and PPO inhibitor seedling damage situations.  This dataset includes:

  • The latest soybean varieties as the research was conducted from 2006-2017.
  • Erect and bushy type varieties in growth architecture.
  • Higher and lower yielding situations.
  • Fourteen irrigated fields and four non-irrigated.
  • Hail events occurring from cotyledon stage to R2 in some of these fields.
  • Crusting in some non-irrigated fields.
  • Seed treated in some fields and others without (determined by grower’s planting date).
  • In some years, pod and seed count data were also collected; the data showed similar numbers of seeds/acre and ultimately yield per acre.
  • Observations of increased plant branching at lower seeding rates and difficulty in telling the seeding rate treatments apart as the season progressed.

Our research data for 11 years shows no statistical yield differences in seeding rates from 120,000-180,000 seeds/acre in 15- or 30-inch rows in silty clay loam or clay loam soils.  Thus, reducing seeding rates is a way to consider reducing input costs for 2018 without impacting your yield.  If you dropped your seeding rate from 150,000 seeds/acre to 120,000 seeds/acre, you could save $10.08/acre, assuming a yield loss of 1 bu/ac, a seed cost of $60 per 140,000 seeds, and a savings of $25.71/ac on seed.

  • Thus, if you plant between 140,000-160,000 seeds/acre, consider dropping your seeding rate to 120,000 and aiming for a final plant stand of 100,000 plants/ac based on our research findings.
  • If you plant at 180,000 or more seeds/acre, consider dropping your seeding rate to 140,000 seeds/acre as a step-wise increment.

Still hesitant? Consider trying this yourself for your location!  Consider using either this Two Population Treatment Design or Four Population Treatment Design.  You also can download the Nebraska On-farm Research app, available in Apple and Android, to help you set up your plot design to obtain scientific results. If you have questions or need help setting up your research project, please contact me or anyone involved with our Nebraska On-Farm Research Network.  To view all the graphs and additional data regarding 15″ row spacing with reduced seeding rates, please check out this week’s UNL CropWatch at http://cropwatch.unl.edu.

Beginning Soil Moisture:  On Good Friday, I installed soil moisture sensors down to 4′ in SoilMoistureTwitterPicnon-irrigated no-till fields at Bladen and Lawrence.  Last week I added three more sites at Clay Center, Superior and Byron.  Thus far, the 3′ and 4′ are dry in all those locations other than Clay Center (only dry at 4′).  At Superior, I could only get the soil probe in the ground 6″ into actively growing rye and 1′ in cover that winter-killed.  I was just curious what kind of moisture existed currently in the southern tier of counties.  I realize planting plans are in place and that we often receive rains in April/May.  Hopefully it provides information that can be helpful in how to use that soil moisture.  If we don’t get necessary rains, you may consider switching to a different crop, growing feed if you have cattle, or not terminating actively growing rye as originally planned but perhaps using it for feed.  Will share graphs next week and I appreciate the growers allowing me to install these in their fields!

Crazy?

Crazy?  Perhaps!  Which according to one of my farmer friends is a little typical of me when I put my mind to figuring out something.  So I had been analyzing my crop water use data from my dryland corn, sorghum, soybean crop water use comparison study.  It’s the one where we had coon problems this year and ended up trapping a skunk!  I noticed how much the soil moisture profile had been depleted and knowing we’ve received minimal precip during fall and winter, I wondered what our soil moisture profile would be for dryland fields by planting.  During a meeting yesterday I thought it would be good to install some watermark sensors to determine soil moisture profile recharge with the pending storm.  Problem was I was at a meeting over 100 miles from my equipment and the pending storm was starting today.  But I was still determined to get them in the ground as early as possible in order to measure the soil moisture status.  So I woke up at 4:00 a.m. to heavy rain.  Great!  It was such a gorgeous day yesterday, and the past week…past month…  The first thing my colleagues had asked me when I told them my idea was “Why didn’t you think of this sooner?”  Answer:  “Guess I needed a precipitation event!”  

So I drive to the field in the rain, get the gear together and start installing the sensors.  First foot went in easy with the rain that had soaked in.  Then it seemed like I tried for 20 minutes (although probably not near that long) putting all my weight on the soil probe to get the 2nd foot in.  Wind-driven rain soaked my jeans since I didn’t have rainpants on…fingers were numb from the cold.  I kept telling myself this will still hopefully be worth it!  On the research data from this field, the second foot was driest of all the crops (was depleted well above plant available water).  I got the third foot in and John, the man who farmed the field appeared.
While he thought it was crazy he graciously volunteered to help as he always does.  He put in the rest of the sensors while I
hooked everything up.  

The last several years we have been blessed to have a fully charged profile going into planting.  Even with this rain/snow event, I’m not sure we will have that in dryland fields in this area of Nebraska.  So I thought it would be interesting to know where we stood before planting and figured the farmers may want to know that as well.  Perhaps a little crazy regarding installing the sensors on such a bad weather day but hoping the data in the end will benefit our farmers and be worth it!

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