Crop Updates: A great deal of timely information was provided in this week’s CropWatch at http://cropwatch.unl.edu including information about high heat and pollination, applying fertilizer during pollination, western bean cutworm scouting, forecasted yields, etc. Please check it out!
Several called me asking about applying fertilizer during pollination. I shared that while
I wasn’t aware of research, I personally was concerned about anything potentially interfering with pollination and that I do recommend 30 lbs of N at brown silk if needed or if you were originally planning split nitrogen apps. This is based on research from Purdue sharing today’s hybrids use 30-40% of their total Nitrogen from flowering through maturity. After discussing with Dr. Tom Hoegemeyer, Adjunct UNL Professor of Practice, he offered the following insights: “Pollination mostly occurs between 8:30 a.m. and Noon. Thus, as a precaution, I would not run a pivot on pollinating corn from 6 a.m. to Noon. When the temperature is 90°F to 95°F, the pollen is killed by heat and is seldom viable past 2 p.m. That leaves lots of time to run pivots, apply N, etc. when it won’t harm pollination. Silks tend to be viable for three or four days at these temperatures, so if a plant isn’t pollinated one day, generally the next day will work just fine. (If nitrogen is needed), I’d recommend that nitrogen go on as soon as practical. Corn nitrogen use is very high during the pre-tassel growth phase and again at kernel growth, from one to three weeks post pollination. About seven to ten days post pollination (before brown silk) lower N will start causing kernel abortion and serious yield loss in corn.” The UNL recommendation for fertigation is to use 30 lb of N with 0.25″ of water or 50-60 lb of N with 0.50″ of water.
Last week also brought questions regarding thresholds and difficulty in finding Western Bean Cutworm egg masses with moth flights at their peak. You can view light trap data from UNL’s South Central Ag Lab thanks to Terry Devries at: https://scal.unl.edu/ltr2018.pdf. There’s also a great article in this week’s CropWatch on how to scout for them, insecticide options, and additional recommendations. Thresholds for western bean cutworm are 5-8% of corn plants in the field containing egg masses or larvae. Egg masses can be difficult to find during pollination with pollen hiding them. ‘Typically’ egg masses are found in the top third of the plant on the upper sides of leaves and near midribs or leaf axils. However, with higher heat, I tend to find them closer to the ears and have even seen masses laid on the ear husks and on the backsides of leaves (not common). While larvae are generally known to move up the plant to feed at the tassels, I’ve seen high heat force larvae into ears earlier. It typically takes 5-7 days for larvae to hatch and the egg masses turn purple just prior to hatching. A number of insecticide options are available for both aerial application and via chemigation; these products are listed in the CropWatch article.
With insecticide applications occurring in corn for both western bean cutworm and also corn rootworm beetles, many have also called or talked with me about the recommendation of fungicide applications. Right now, I haven’t found gray leaf spot above 3 leaves below the ear leaf in several counties. There’s been some mis-diagnosing bacterial leaf streak as gray leaf spot. Southern rust was just confirmed in a Kansas county this week, but we still have yet to confirm it in Nebraska. Even the longest residual products won’t get us through August if a fungicide application occurs now. I can appreciate that economics are tight so the thought is to save an additional application cost by applying a fungicide now with the insecticide. And, I can appreciate economics are tight regarding why apply a fungicide right now when disease pressure doesn’t warrant it? Perhaps, at least those of you with the ability to chemigate could consider waiting till disease pressure warrants it for your field, if it does. Always in the back of my mind is the need for late-season protection with southern rust eventually showing up and gray leaf spot often worse then.
My perspective is from a resistance management and research-based one. We have 5 total modes of action for fungicides with 2 of them being in nearly every fungicide product we use in corn, soybean, and wheat because they work against foliar fungal pathogens. At some point, our pathogens will also adapt, as we’ve seen our weeds and insects do…it would be like losing our ability to control gray leaf spot and southern rust similar to palmer amaranth on the weed side. In Nebraska, Dr. Tamra Jackson-Ziem’s research has not shown an automatic yield increase to fungicide application in the absence of disease. And, it has also not shown an automatic yield increase when applied at tassel. In a high heat and low disease year like 2012, there were no statistical yield differences with fungicide application vs. the untreated control. Even in years with some disease pressure such as 2008-2010, she found no statistical yield differences between when various products were applied from Tassel through Dough stages. In high disease years, her research shows the benefit of fungicide application for reduced disease pressure and increased stalk strength. Fungicides are great tools to help us with disease pressure and stalk strength. Just would encourage all of us to consider when we really need to apply them and to understand that research in Nebraska does not automatically show increased yields with the use of them or with the timing of Tassel/Silking vs. later in the year. Also, hybrids may vary in their response due to disease susceptibility and other factors. Not all her data is listed at this site, but you can view it for yourself at: https://go.unl.edu/ni3y.
Bagworms: I’ve been seeing shelter belts and various trees turning brown from heavy
bagworm infestations. Please be checking your trees if you are noticing them turning brown. Additional information can be found at: https://go.unl.edu/rgju.
Crop Update: A few diseases started showing up the past few weeks in various portions of eastern and south central Nebraska. Phytophthora root rot in soybean is perhaps the
most common in both areas. We normally think of this disease as seedling damping off and death; however, it can also affect plants later in the season. What surprised me was how much we are seeing it this year in higher ground and sidehills instead of the typical lower ground we often see it on. Dr. Loren Giesler, Extension Soybean Pathologist said that in situations where we’ve had dry conditions followed by heavy rains (as we have this year), especially on clayey or soils prone to compaction, Phytophthora can also affect plants. He has a few videos along with additional information at the following website: https://go.unl.edu/tdfh. Symptoms characteristic at these growth stages include wilting of plants during the day with leaves eventually turning yellow-brown-gray and remaining on the plants. Also, look for a brown stem lesion that goes from the soil line upward about 4-6″. Some of these plants are also snapping off at the soil line. For those experiencing Phytophthora this year, future management includes:
- Using resistant varieties including a combination of good partial resistance and an Rps gene. Partial resistance alone will not be as effective during early growth stages or under high disease pressure.
- Cultural practices include anything that can improve soil drainage and compaction.
- Seed treatment fungicides containing mefenoxam or metalaxyl should be used and you may need to consider a higher rate of them.
Regarding corn diseases, bacterial leaf streak (BLS) has greatly increased on more
susceptible hybrids since rain events. Early lesions can look very similar to gray leaf spot, so it’s important to correctly identify the two. The margins of BLS are wavy vs. those of gray leaf spot are more blunt. Both can have yellow margins when backlit by the sun. Fungicides are not effective against BLS and hybrids do vary in their tolerance to this disease. It’s important to scout fields as we may see an increase in fungal diseases due to the humidity, leaf wetness, and recent rain events. Southern rust has taken awhile to develop in the southern U.S., which is somewhat unusual, yet many states have been in drought this year too. As of July 5th, southern rust has been confirmed in Georgia with one suspected sample in a Missouri county. You can watch the map at: http://ext.ipipe.org/ and follow @corndisease on Twitter for the latest on corn disease findings in the U.S.
Trees: With numerous wind storms, the following resource has a lot of great information regarding pruning storm damaged trees correctly and questions to ask tree care services regarding tree pruning: https://go.unl.edu/94fm.
Agronomy Youth Field Day: All youth ages 9-18 years old are invited to the 3rd Annual Agronomy Youth Field Day. Youth will have exciting educational experiences while discovering Science & Agronomy/ Irrigation / Mechanized Agricultural careers for producing Nebraska crops! The field day will be held Wednesday, August 8 from 9 a.m.-3 p.m. at Nebraska College of Technical Agriculture Educational Center in Curtis, NE.
Hands-on activities (for all age levels) will focus on pest management, equipment technology, crop growth, soil management, precision farming & center-pivot irrigation technology. Several Nebraska Extension Cropping & Water Systems and 4-H Youth Development Educators along with Nebraska College of Technical Agriculture in Curtis Agronomy / Ag Mechanics Department professors will be sharing the researched based information with the students.
Participants will gain important life skills while discovering the science behind producing Nebraska crops. The six-hour field day is a great opportunity for ALL the youth to learn more about the agronomy industry and increase their basic understanding of science, ag literacy, a technology & STEM while exploring careers. Parents/Adults are welcome and lunch will be provided.
Reserve your spot today by registering online at: https://go.unl.edu/agronomyyouthfieldday by August 3, 2018. For more information (or if trouble with registration) contact Nebraska Extension Frontier County at 308-367-4424 or email 4-H Educator Kathy Burr at firstname.lastname@example.org.
Last night brought much-needed rain and grateful for that! From driving today, also saw some crop damage due to flooding, hail, and greensnap. So sorry for those of you most affected by greensnap and hail!
Last month I focused on counting my blessings-which are many! One has been the wonderful rains we’ve received at critical times of being so dry. The crops overall are beautiful right now regarding overall color and especially soybean weed control! Another blessing has been the opportunity to serve people in several counties the past 2+ years. I’m grateful for the extra time to serve my former area while also getting to know people in my new one! Grateful that relationships can be maintained and built regardless of where a person works or lives! I’m also grateful that we’ve been able to hire an individual who I believe to be a good fit for the Clay County Crops/Water Educator position with accountability region of Nuckolls, Thayer, and Fillmore counties. Michael Sindelar begins this new role on July 2. Michael conducted graduate research at South Central Ag Lab (SCAL) near Clay Center, so he is familiar with the area and with SCAL. His major advisor was Dr. Humberto Blanco, UNL Soil Scientist, and one of their projects was looking at soil impacts on corn residue removal and any impacts of adding cover crops into that system. I asked Michael to provide a brief background so I could introduce him to you.
“Hi, I am Michael Sindelar, the new cropping and water systems educator based out of Clay Center, Nebraska. I was born and raised in Lincoln, Nebraska. However, I was exposed to agriculture at a young age as my father would take me to the family farm located near Richland, Nebraska in Colfax county to “help” with the farm work. I joined the Navy in 2005 and served until 2010. I was a cryptologist collective (CTR) and worked in military intelligence. I was stationed out of Hawaii for my enlistment. I had the opportunity to see parts of the pacific and spent one year deployed in Afghanistan where I collected intelligence and conducted combat operations. After having fun for a couple of years I got my act together and earned a bachelor’s degree in Agronomy from the University of Nebraska. This spring I completed my master’s degree in Agronomy with a specialization in soil and water science from the University of Nebraska. I spent most of my master’s degree studying how changes in soil management affect soil water storage, recharge, and heat as storage and transfer through the soil. I look forward to starting my new position on Monday. I sign most of my emails using V/R which is a carryover from the military meaning very respectfully.”
There will still be a transition time of various projects currently underway with July 4 this week and Clay County Fair the next. Please be sure to introduce yourself to Michael when you see him!
When I transitioned to York/Seward a few years ago, I wrote a column entitled “Blessed”. I’ve been blessed to serve the people of Clay/Nuckolls/Thayer/Fillmore Counties a few extra years. And, I will always be grateful for relationships built and the opportunity you gave me entrusting me to help you with diagnosis and farming decisions! I hope you will also give Michael that same opportunity as he begins in this new role!
Tree Branches: Many of us had tree branches down again after the winds. After the last event, a few farmers mentioned to me that it’s frustrating when town people dump their branches in their farm ditches leaving the farmers to pick them up. So, while it’s only common sense and respectful to not do this, I said I’d mention to please not do this (although I’m uncertain if they would be reading my column)!
Glyphosate Resistant Palmer Amaranth Field Day: View field demonstrations and hear from experts at the Glyphosate-Resistant Palmer Amaranth Management Field Day Wednesday, July 11 at Carleton. The event is free and will be held from 8:30 a.m. (Registration) with program from 9 a.m. to 1 p.m. Keynote speaker will be Aaron Hager, associate professor and Extension weed scientist at the University of Illinois at Urbana-Champaign. He will speak on the biology of Palmer amaranth and current research on its control in corn and soybean, including in new technologies such as Xtend and Enlist soybeans. Populations of Palmer amaranth in Nebraska have been found resistant to glyphosate, atrazine, HPPD, and/or ALS herbicides, said Amit Jhala, field day coordinator and Nebraska Extension weed specialist. Demonstrations include:
- How row spacing and herbicide programs can affect glyphosate-resistant Palmer amaranth control in Roundup Ready 2 Xtend Soybean;
- Management of Palmer amaranth in: Balance GT/Liberty Link Soybean (resistant to isoxaflutole and glufosinate) and Enlist E3 Soybean (resistant to 2,4-D choline, glyphosate, and glufosinate;
- Critical period of Palmer amaranth removal affected by residual herbicides in Roundup Ready 2 Xtend Soybean.
These in-field demonstrations and research projects were funded by a grant from the Nebraska Soybean Board. Register online at http://agronomy.unl.edu/palmer to ensure appropriate meals and tour rides. Three Certified Crop Advisor (CCA) credits will be available for attending. If there are questions about registering, please call 402-472-5656. Directions: From Geneva go south on Hwy 81 for 14.6 miles. Turn west onto Hwy 4 and go 5.3 miles. The field day will be on the south side of Hwy 4 between C Street and Renwick Street in Carleton. (GPS: 40°18’24.7”N 97°40’29.0”W). Partial funding for this field day was provided by the Nebraska Soybean Checkoff and Nebraska Extension.
Grateful to receive rain to help the first and second foot profiles at these locations! Interesting how after 2-3″ of rain on June 20th that the county roads were already dusty and I could drive the dirt lanes in these fields the next day. I will add York, Seward, and Clay soil moisture in my next post.
Crop Update: What a blessing to have rain this past week! Grateful for how it provided much needed moisture into the top two feet in many cases. Updated soil moisture status will be at http://jenreesources.com. Some in our area and in other parts of the State received wind, hail damage, and flooding to crops. This week’s CropWatch at http://cropwatch.unl.edu shares information for those situations. A few summarizing points: for those with greensnap or with severe hail damage, you may wonder what potential yield may be based on your planting date and current plant stand. The following chart from Iowa State University and explanation of how to understand it may be helpful: https://crops.extension.iastate.edu/cropnews/2009/05/assessing-corn-stands-replanting.
For those with flooding, corn in the V7-10 leaf stage can survive for about 7-10 days in flooded water. Temperatures above 86F can result in greater stress on those plants than if the temps remain cooler than that during that time. Another consideration for the future, it’s not uncommon to find a disease called ‘crazy top’ of corn when the tassels begin to emerge. We’ve seen this the past several years where creeks or areas along waterways or field edges were ponded. There’s nothing you can do to prevent this.
For those with hail damage, damage from V7-10 leaf corn can result in a number of situations depending on the severity of hail. Minimal yield loss is assumed for leaf damage in crop insurance charts. Final plant stands will be important which will account for broken off plants that don’t recover. Stem bruising also isn’t factored in. For corn, bacterial diseases tend to be my larger concern at these growth stages. Bacterial top rot is one in which the plant dies from the top down and has a strong odor to it and creates a soft, slimy mess. Goss’ wilt is another concern-particularly systemic Goss’ wilt. You can check for this if you have a dying plant that doesn’t have a soft rot by taking a
cross section of the stem and looking for discoloration of the vascular bundles. You can also send plants like this to the Plant and Pest Diagnostic Lab in Lincoln for confirmation.
Regarding fungicide use on hail damaged corn, Iowa State and the University of Illinois did studies finding similar results. Both found no statistical difference in applying a fungicide vs. the untreated check in spite of small numerical differences. Regarding timing, the Iowa State study simulated hail damage at tassel and applied fungicide an average of 3 days and 8 days post-hail. There were no statistical differences on yield of the timing of the applications either. They did find statistically less fungal diseases in the hail-damaged plots vs. the non-hail damaged plots and speculated it was due to more air flow and less leaf area available for disease to occur. I have observed that fungicide can help with stalk strength and maintaining whatever green tissue remains when we had the 2013 hail storm in Clay County at brown-silk to blister corn. But this early, it’s hard to justify a fungicide application based on the data that’s available. If you’re interested in testing this for yourself, the following is an on-farm research Fungicide Protocol for Hailed Corn and Soybean.
For hail damage on soybean, many of the beans are at flowering or approaching flowering. Again, stem bruising isn’t counted in crop insurance assessments. I haven’t really observed bacterial or other disease issues necessarily from stem bruising in soybean. What tends to be more of an issue is those plants hardening off and becoming brittle to walk through. For soybeans, the blessing is that often new buds form and you will see increased branching which can help with canopy closure…it just can hurt right now when soybeans were already near canopy and we’re trying to reduce additional inputs for weed control. Things to consider are that pods may be closer to the ground from this increased branching and you may need to harvest earlier to help with getting beans that become brittle before snapping off in wind storms. I leave plant stands of near 60,000 plants/acre based on our soybean pop studies that received hail damage. If you want to prove any replanting differences to yourself, you may wish to consider the following Soybean Replant Protocol. We’d recommend waiting on herbicide apps till some new growth occurs, which is difficult when I’ve watched palmer essentially be not affected by hail and put on two new leaves within a few days in the past. Last year we started making herbicide apps 5-7 days post-hail. Additional hail resources are at a new resource called ‘Hail Know’ at: https://cropwatch.unl.edu/hailknow. There’s a lot of info I haven’t transferred to this site yet…but you can view photos and comments on hail recovery at numerous growth stages over time at my blog under the ‘Storm Damage’ category: https://jenreesources.com/category/storm-damage-2/.
Last week I shared the following video regarding determining timing of off-target dicamba movement to soybean: https://youtu.be/rQid7-vX-TU. Sharing again with an increase in the number of fields that were experiencing cupped symptoms last week.
This past week contained many off-target herbicide concern calls. Prior to Memorial Day I had made a note that post-herbicide applications to corn began in much of the area and anticipated phone calls to begin in about two weeks. Most of the conversations this week were more FYI to let me know they had soybean leaf cupping.
Here’s a few things to consider if you are having soybean leaf cupping.
- First, was a post-herbicide application made to your soybeans? If so, check for any potential tank contamination (Check out this CropWatch article: https://go.unl.edu/fnig). If not, check out this publication (http://ipcm.wisc.edu/download/pubsPM/dicamba2004.pdf) to determine if any of the criteria mentioned could possibly be contributing to the problem.
- Determine how old the plant is by asking when the soybean was planted and even better when it emerged. A soybean plant will produce a new node every 3.75 days.
- To determine the timing of damage, I count the total number of nodes on the plant to the last trifoliolate where leaf edges are not touching. The total number of nodes may differ in different parts of the field such as irrigated and non-irrigated especially after herbicide damage and drought-stress (Example 8 nodes irrigated and 6 non-irrigated). Take the number of nodes X 3.75 to get total approximation of plant age. Then count back on the calendar to determine approximate emergence date. If I use 8 nodes in this example X 3.75 = around 30 days ago the plant emerged.
- I then count the number of nodes to the very first damage I see on leaves (Example 3). Multiply this number of nodes times 3.75 and count forward on the calendar from emergence to that date. For instance, in this case, damage occurred around 11 days after emergence.
- I also like to count how many completely unfurled trifoliolates are affected (Example 6 trifoliolates). Take that number and multiply by 3.75 (Example 6 X 3.75= approximately 23 days ago the damage occurred).
- In this example, it worked to count either direction (from emergence and from current date) to determine approximate timing of off-target movement occurring. In all the situations I’ve looked at thus far, the timing goes back to around Memorial Day with post-dicamba herbicide applications applied to corn.
- Auxin-like herbicides affect only cell division. Thus, fully developed leaves (no longer expanding via cell division) are not affected even though they may be expanding by leaf cell enlargement. Only the tips of the newest exposed soybean leaves may experience damage to dicamba as they are still undergoing cell division. Otherwise, it can take 7-14 days for leaf damage from dicamba injury to appear on susceptible plants and damage will occur typically 4-6 nodes. This is because dicamba is also translocated once inside leaf cells. Thus it impacts cell division of the leaf primordia at the stem apex. We may not even see those leaves yet because they are still enclosed in the stem apex tissue.
- In a matter of weeks, affected fields can go from appearing to have minor damage, to looking really bad, to growing out of damage. It looks worst when those affected nodes push upward giving the field a grayish/white cast to it as the leaves become much reduced in size and are tightly cupped. Eventually the leaves will begin to look more normal again in time (as long as a second off-target movement doesn’t occur).
What can you do? Water via irrigation and/or rainfall is the best recovery tool for dicamba damage. Waiting is another. We’re blessed to grow indeterminate soybean in Nebraska which continues to produce nodes and leaves upon flowering which allows our soybean to grow out of damage.
- Wait till harvest to determine any yield impacts if there are areas impacted vs. those which aren’t. Otherwise, field-scale damage is difficult to discern yield impacts.
- You can talk with your neighbors/ag retailers regarding what they sprayed. In our area of the State, it’s often difficult to pinpoint the source of off-target movement with so many applying dicamba products to corn for palmer control often around the same time-frame. Now that post-apps to soybean are also occurring, that may also become a challenge. Of all the fields I visited last year, less than a handful of farmers sought any sort of compensation and those were more often due to tank contamination issues. If you wish to pursue that route, you need to file a complaint with the Nebraska Department of Ag.
- For future dicamba applications, check out these best management tips: https://go.unl.edu/97ok.
- For those of you reading this in a source outside of my blog, I created a video to hopefully be more visual and clear on understanding this method of diagnosing timing. You can check it out at my YouTube site: https://www.youtube.com/user/jenreesources.
Bagworms: It’s June and one of my top questions has been “Have I found bagworms yet?” Well, they’re now feeding and forming new bags on junipers and spruces. What you’re looking for are not the old bags at this point, but very small (fingernail size) new bags that move as the caterpillar is feeding and making the larger bag. This video from Backyard Farmer (https://youtu.be/05A2quj9nO4) does a great job of showing various stages of bagworms and sharing on control methods. Check it out!
Irrigation Scheduling Workshops: Steve Melvin, Extension Educator in Hamilton/Merrick Counties asked I share about upcoming irrigation workshops hosted by UNL and Upper Big Blue NRD. The program will focus on installing the equipment and making irrigation scheduling decisions using the data generated by Watermark sensors. The workshops will be held from Noon-1:30 p.m. on June 25th at the Corner Café, 221 Main St in Stromsburg and also at the same time June 28th at the Hordville Community Building, 110 Main St. The Upper Big Blue NRD will provide the lunch. The first presentation will be Installation of Watermark Sensors and Data Logger presented by Dan Leininger, Water Conservationist with the Upper Big Blue NRD. The second will be Deciding When and How Much Water to Apply Using Watermark Sensor Readings presented by Steve Melvin. The irrigation scheduling strategies presented in Steve’s presentation can be used with any soil water monitoring equipment data. More information is available by calling Steve Melvin at (308) 946-3843 or visiting https://extension.unl.edu/statewide/merrick/.
Thank you to Tena with Faller Landscape in York and to all the youth who participated in our 4-H landscape design workshop and helped plant the Nebraska area! It will hopefully be beautiful for fair!
Crop Update: Rain continues to be spotty and windstorms have resulted in various levels of greensnap in some fields. Overall crops are growing and getting a decent canopy. It’s been interesting watching the radar on weather apps as so often they look like precipitation should be occurring yet that’s not always the case. Grateful for all of you who share crop updates-including things such as impacts on hay crops, pastures, etc. and for our farmers working with me on soil moisture monitoring. I was told this past week of the impact of our groundtruthing on the drought monitor; radar would make it appear we’re not as dry as we truly are. So just wanted to share that with you-that your input is important as we then share that input with those who work with the models and maps! I plan to get soil moisture sensors installed in non-irrigated fields in York, Seward, and Clay this week as well.
Soil Moisture Sensors Tips: With cultivating and hilling progressing, some are now looking at getting soil moisture sensors installed. If you utilize watermark sensors, the following are some tips I’ve learned.
Test sensors with wet/dry process to remove all air bubbles:
- First, make sure sensors read 199.
- Then, soak sensors for at least 24 hours. They should read 10 or less (Jenny’s note-I realize they may read this in a matter of minutes to hours but it’s our best practice recommendation to ensure all air bubbles are removed).
- If they don’t read 10 or less, gently rub any soil loose on them with your fingers (don’t use a brush) and allow to continue soaking for another 24-48 hours. If they still don’t read under 10, I don’t use them.
- Best practice is to then allow the sensors to completely dry out again to 199 to complete the wet/dry process. (Jenny’s note: I realize, due to time constraints, many sensors get installed once they have been soaking and never go through the complete drying process).
- Avoid installing sensors in saturated soil conditions in clayey soils. Doing so allows a thin clay film to develop on the sensors which then affects readings .
- Prior to installation, the sensors should be soaked again and installed wet. The soaking process only takes a matter of minutes to get back to 10 or below. I carry the water bucket with sensors with me into the field.
- When soaking, water moves into the PVC pipe, thus it can take time for the water to drain providing accurate readings if not removed. Some sensors have a hole drilled in the PVC pipe above the sensor to allow water to drain. Otherwise, it’s important to remove the caps and tip the sensors over to dump any water that has accumulated in the PVC pipe during the soaking process. I then put the cap back on, take my hand and wet the PVC pipe with water so it pushes in easier. Some like to use WD-40 but my concern with that is it getting on the sensor affecting readings.
- Install all sensors where the sensor itself sets using an ag consultant tube (can be 12 or 18 inches). An ag consultant tube has a slightly smaller diameter that provides a tight fit for the sensor. Use a regular soil probe for the foot above that. For example, for 1’ sensor, I use ag consultant tube. For 2’ sensor, I use regular probe for first foot and ag consultant tube for second foot. For 3’ sensor, I use regular probe for first 2 feet and ag consultant tube for third foot. The reason for this is in clayey soils that are wet, there’s greater resistance to pushing in that sensor, so this is one way I’ve found which is easier for someone like me to push them in. (Jenny’s note: many have installed sensors with a regular soil probe through the years and that’s also fine. Just know that you may see more water run along side of tube before soil makes a tight fit around where sensor is located. I’ve just found less issues with this when I use the process described above).
- NEVER pour water into the hole or make a slurry. Make sure the sensor hits the bottom of the hole as air gaps can make the sensor readings inaccurate. Some people find it better to not remove the entire amount of soil for a specific depth and then push the sensor the rest of the way till the correct depth is obtained. I’m not always strong enough to do that so do what works for you as long as the sensor is at the correct depth and there’s no air gaps.
- Make sure to fill in any gaps around the sensor with soil and make sure there’s no soil cracks around the sensors.
- Make sure to mark each sensor and flag them well.
- Sensor readings should equilibrate with the soil within 48-72 hours but especially within a week.
- If a sensor starts reading really dry, before replacing it, I often remove it and reprime it in the field. This can be done by re-soaking in water for 1 minute or so till it goes back below 10 and then reinstalling in same hole. If it doesn’t go below 10, I replace it. If it reads strange the next week, I also replace it.
- A reminder to use distilled water in the tube and to fill the ceramic top when you’re also filling the main tube. I usually fill the ceramic top and wait for it to soak up a little then fill again.
- Prime the ET gage ensuring no air bubbles are in the second tube with the stopper. I always overfill the ET gage to help with priming and ensuring there’s no air bubbles.
- Excess water can be removed and also air bubbles can be removed by gently pulling down on the glass site gauge tube at the rubber base and releasing extra water from it. Air bubbles can also be released in this process. Place the site gauge tube back in place when you are at a water level between ‘0 and 1’. Then place one red marker ring on that beginning start level.
- I always plan to refill the ET gage when it gets down to ‘9’ on the site tube.
- The green canvas cover should be replaced at least every 2 years and be sure to dust it off and the white membrane below it.
In another column I’ll share how to use the two tools together for irrigation scheduling. All videos and charts with more information can be found at: https://water.unl.edu/category/nawmn. This is a checklist I made awhile back with Daryl Andersen which has more detail and could honestly be updated: http://www.littlebluenrd.org/pdf’s/forms/etgage_sensor_checklist.pdf but may also be helpful.
Tree Damage: Recent windstorms have caused for many downed branches and even some trees. When removing broken branches or dead branches, it’s important to prune correctly for tree health. Correct pruning of larger branches can often involve 3 cuts per limb. The first two cuts are made away from the trunk of the tree to remove most of the weight of the limb. The third cut is near the trunk itself at the bark collar ridge where the tree will eventually seek to heal. I like this Backyard Farmer YouTube video as a good visual of correct pruning: https://youtu.be/9cl0Qxm7npk. Pruning is best done in the dormant season of February and March. It’s best avoided in April and May when trees are putting energy into new leaves and in the fall as fall pruning can result in growth instead of the tree preparing for and going into dormancy. Some great resources with more information on proper pruning are: https://go.unl.edu/v9uf, https://go.unl.edu/gdb9, and this blog post https://jenreesources.com/2014/04/20/proper-tree-pruning.