Blog Archives
Sprinkler Packages and Wind
Grateful for those who paid the ultimate sacrifice for our freedom and to their families left behind. May we never forget that freedom isn’t free! This week sharing excerpts of an article that my colleagues wrote on sprinkler packages in windy conditions. The full article is here: https://go.unl.edu/f90p. “Efficient irrigation relies on minimizing water losses and maximizing the portion of applied water that reaches the crop root zone. …Past UNL research has shown that evaporation losses are often less than 4% of the applied water, though potentially approaching 10% with sprinklers on top of the pipe under high pressures, creating small droplets. In contrast, wind drift can lead to larger losses than evaporation by physically moving water droplets away from the intended target area. This not only reduces irrigation efficiency but can also create uneven water distribution across the field.
…a field evaluation was conducted recently at the UNL’s South Central Agricultural Laboratory (SCAL) near Clay Center, Nebraska. The evaluation was conducted with sustained winds of 10-15 mph and gusts reaching 20-25 mph, conditions that are not uncommon during the irrigation season in Nebraska. The sprinkler industry offers a wide range of sprinkler packages designed to meet different irrigation goals. In this test, three sprinkler configurations from Nelson Irrigation Corporation were tested: 1) Orbitor with blue plate (large droplet design). 2) Sprayhead with tan bubble-wide plate (bubbler-style). 3) Sprayhead with purple plate (fine droplet design).
All these sprinklers were mounted on drops at 9 feet aboveground. Each configuration was assessed based on observed wetted diameter, droplet size and behavior, and overall performance under windy conditions. In addition, a catch-can test was conducted to evaluate how closely the applied water matched the target depth programmed into the system.
The Orbitor sprinkler performed consistently under windy conditions and maintained a stable water distribution pattern. It also produced a relatively large wetted diameter: approximately 40 feet in the direction of the wind. This broader coverage can help reduce application intensity and thus, the risk of generating surface runoff.
Sprayhead with Tan Bubble-Wide Plate: The bubbler configuration produced larger droplets and demonstrated strong resistance to wind drift. The wetted diameter was less than half of Orbitor’s at approximately 18 feet in the direction of the wind. These characteristics make this type of sprinkler particularly effective at delivering water to the intended area when wind is a concern. However, some localized ponding was observed during the test, even at a relatively low application depth of 0.25-inch. This suggests that the higher application intensity associated with a smaller wetted diameter may increase the risk of runoff, particularly in soils with lower infiltration rates or in fields with slope.
Sprayhead with Purple Plate: This configuration produced the smallest droplet size and, under calm conditions, would be expected to create a relatively narrow wetted pattern. However, under the windy conditions during the test, performance was significantly compromised. The fine droplets were highly susceptible to wind drift, to the extent that the boundaries of the wetted area could not be clearly identified in the field. …this type of sprinkler configuration may result in reduced irrigation efficiency and non-uniform water distribution when used in windy environments.
The results of this field test reinforce a key point: sprinkler selection plays a critical role in determining how effectively irrigation water is delivered under windy conditions. In windy conditions, droplet size matters. Sprinklers that produce larger droplets are less likely to be carried away by wind, improving the likelihood that water reaches the soil surface where it is needed. There is a tradeoff between drift and application intensity. While larger droplets reduce drift, they are often associated with smaller wetted diameters and higher application rates, which may increase the risk of ponding or runoff. …Producers are encouraged to evaluate their current systems, consider how they perform under windy conditions, and work with irrigation professionals to select and maintain sprinkler packages that align with your field conditions and water management goals.”
2015 Nebraska Ag Water Mgmt Network Meeting
April 2, 2015 is the date for the 2nd annual Nebraska Ag Water Management Network (NAWMN) Meeting! Come hear the latest in irrigation research and share with your peers during the innovation sharing and Q/A discussions. There’s no charge but please RSVP to Gary Zoubek at (402) 362-5508 or gary.zoubek@unl.edu.
Online Irrigation Cost Calculator
Have you ever wondered what fair price could be charged for the water your pivot delivers to an adjacent neighbor’s field? Or have you wondered what it would cost if you changed to a different fuel source?
The Irrigation Cost calculator was first developed by Tom Dorn, retired Extension Educator, and was a tool I used and recommended to farmers and landlords in various situations such as those above. The tool has now been redesigned as an online tool with updated numbers built in. Data is entered by you for your operation and calculations are made on a remote server. You can then choose to save your data for later reference or to input various options to compare costs. Calculated output includes fixed and variable costs calculated per-acre and per-acre-inch of water applied. The following information is from Roger Wilson, Extension Farm Management Specialist and Budget Analyst.
To use this tool, you’ll need to gather some key information:
- Operating data such as interest rates, wage rates, area irrigated and inches applied, diesel price or electricity rates, and drip oil price. (Energy costs may be estimated from pumping lift, system pressure, and pumping plant efficiency or from historical data such as past energy costs, past fuel prices or electrical rates, and past application rates.)
- Ownership costs such as the estimated replacement price, expected life and the salvage values for the well, pump, power plant, gear head, and sprinkler system.
Fair Share Feature for Adjoining Parcels
After these costs have been calculated, you can use the “Fair Share” feature to estimate the cost for running a center pivot over adjacent land. Additional data needed for these calculations are the number of adjacent acres to be irrigated and the estimated acre inches that will be applied. The “fair share” can be calculated on the added acres irrigated or on the amount of water applied. This feature has two components: fixed and variable costs. The fixed cost is an annual cost and the variable cost is for acre-inches of water applied.
User Guide
The Irrigation Cost Calculator web page includes a video on how to use this tool.
Mobile Apps for Irrigation Management
Earlier this year UNL Extension introduced three mobile apps to aid in irrigation management, which are described further in UNL CropWatch in the links below:
Agriculture Irrigation Costs App. Calculates ownership and operating costs for center pivot and gated pipe irrigation systems and the most commonly used energy sources. This tool is based on the same resource as the Irrigation Cost Calculator web tool described above. The Web app is a “quick and dirty” means to calculate costs, while the mobile app offers more options for testing and analyzing various options. The mobile app offers side-by-side comparisons for systems that use different energy sources, analysis of gated pipe as well as center pivot systems, separation of landowner and tenant costs, and calculating yield increases necessary to pay for application of an extra inch of water.
Irrigation Pumping Plant Efficiency. Helps you identify irrigation pumping plants that are underperforming and need to be adjusted, repaired, or replaced with a better design.
Water Meter Calculator App. Calculates the amount of water pumped by irrigation pumping plants and can store data such as field size (in acres), flow meter units, and allocation and annual irrigation caps for each field.
Center Pivot Irrigation Short-Course
Hope to see you in Clay Center on February 11 for this upcoming meeting!
(Please click on the picture to enlarge the text.)
Crop Update 6-20-13
The sun has been welcomed and crops are rapidly growing in South Central Nebraska! Corn right now is between V6-V8 (6-8 leaf) for the most part. Quite a few farmers were side-dressing and 
hilling corn the past two weeks. It never fails that corn looks a little stressed after this as moisture is released from the soil and roots aren’t quite down to deeper moisture.
Installing watermark sensors for irrigation scheduling, we’re finding good moisture to 3 feet in all fields in the area. The driest fields are those which were converted from pasture last year and we want to be watching the third foot especially in those fields. Pivots are running in some fields because corn looks stressed, but there’s plenty of moisture in the soil based on the watermark sensor readings I’m receiving for the entire area. So we would recommend to allow your crops to continue to root down to uptake deeper moisture and nitrogen.
The last few weeks we observed many patterns from fertilizer applications in fields but as corn and root systems are developing, they are growing out of it. We’ve also observed some rapid growth syndrome in plants. This can result from the quick transition we had from cooler temperatures to warmer temperatures, which leads to rapid leaf growth faster than they can emerge from the whorl. Plants may have some twisted whorls and/or lighter discoloration of these
leaves, but they will green up upon unfurling and receiving sunlight. This shouldn’t affect yield.
Damping off has been a problem in areas where we had water ponded or saturated conditions for periods of time. We’ve also observed some uneven emergence in various fields from potentially a combination of factors including some cold shock to germinating seedlings.
We began applying sugar to our on-farm research sugar vs. check studies in corn. We will continue to monitor disease and insect pressure in these plots and determine percent stalk rot and yield at the end of the season.
Leaf and stripe rust can be observed in wheat fields in the area and wheat is beginning to turn. We had some problems with wheat streak mosaic virus in the area again affecting producers’ neighboring fields when volunteer wheat wasn’t killed last fall. Alfalfa is beginning to regrow after first cutting and we’re encouraging producers to look for alfalfa weevils. All our crops could really use a nice slow rain right now!
Preparing Irrigation Scheduling Equipment
It’s wonderful receiving the rain we did, seeing how quickly planting progress came along, and how quickly corn is popping out of the 
ground! Being mid-May, it’s time to get our Evapotranspiration (ET) gages out. A reminder to only use distilled water in the gages, make sure to fill up the ceramic top portion of the gage before inserting the stopper, and gently dust off the ceramic top and replace the white membrane and green canvas cover. We recommend replacing those membranes and covers each year so if you need a new one, please let the Natural Resources Districts (NRDs) or me know and we’ll get you a new one! For those of you recording ET information online, please be sure to do so consistently each week to help your neighbors and crop consultants.
Early after crop emergence is the best time to install watermark sensors. For those of you with watermark sensors, read them to ensure they read 199 kpa (dry). Then “prime” them first by soaking them for 24 hours in water to ensure all the air bubbles have been released. The sensors should have a reading of 10 kpa or below to be considered good. If they read higher than that, either continue soaking them another 24 hours and read them again, or plan that they no longer are reading correctly and replace them with others from the NRDs. Remember after soaking sensors that water moves up into the PVC pipe via capillary action, so be sure to dump the water out of the pipe 
as well.
When installing the sensors, be sure to install them wet, drain excess water, and look for areas that are not compacted, avoid tractor wheel tracks, and look for even spacing of plants. Carefully install without breaking off any plants (thus easier when plants are small!). It’s also important not to install sensors into extremely wet fields. What we have found is that a thin soil layer can cover the sensor when pushing it into the soil of very wet fields. When that soil layer dries, it can provide a reading of 199 saying the sensor is dry when it truly isn’t. If this happens to you, simply remove the sensor, rewet for one minute and re-install. It should be acclimated to field conditions within 48 hours. If you have any questions regarding the installation process, please let the NRDs or your local Extension Educator know. You can also view videos of the installation process and receive additional information to answer your questions.
Corn Planting Rate Research & Recs
Even with recent rain and snow events, the subsoil is still dry. You may be wondering,
“What should I do regarding corn planting rates in 2013?”
A few weeks ago, UNL Extension held our on-farm research meetings to share our 2012 Corn Planting Rate results for irrigated and dryland conditions. I always enjoy hearing our farmers share why they were interested in a certain trial and what they found out as a result.
Our farmers followed protocols of 28K, 32K, 36K, 40K (40,000 seeds/acre) or 30K, 34K, 38K, 42K/acre for irrigated production and 18K, 22K, 26K, and 30K for dryland production. 
The results since 2010 continue to show us that each individual hybrid varies in its response to increasing populations; however, there is a general trend with newer hybrids that increasing population results in increased yields. Dr. Tom Hoegemeyer, UNL Agronomy Professor of Practice spoke about how our hybrids have genetically come so far in combating various stresses while maintaining yields. We know that many seed companies have conducted research to determine the population calibration curve for each hybrid to determine best recommendations for you. Thus, we’d recommend that you check with your seed dealer to determine which hybrid may fit best at which population for your operation.
Even with this data, you may question if that’s truly the best population for your field; that’s where on-farm research comes in! We recommend testing the recommended population against a higher and lower population with at least 4000 seeds/acre difference in planted population-whether irrigated or dryland. With today’s technologies, it’s not very difficult to test seeding rates for different hybrids for yourself!
So what rate should you plant this year? In the majority of our irrigated studies, economically, many hybrids maximized yields and economic returns between 32,000-36,0o0 seeds/acre. Again, this is very hybrid dependent so ask your seed dealer what he/she would recommend and test for yourself!
Regarding limited irrigation, UNL research has actually shown a negative effect of lost yield by backing off population too far in a dry year. 
Tom’s recommendation was for dryland in Eastern Nebraska, most hybrids even with the low soil moisture profile should be ok with planting 24,000-28,000 seeds/acre. I realize we have essentially no moisture in our profile. But taking probabilities of rainfall events, March-May is usually pretty good and we don’t want to short-change ourselves in yield by planting too low of populations. For Central into Western, NE, I feel 20,000-22,000 seeds/acre will work for many hybrids. Our genetics have come so far since we finished the last drought in 2007 and were planting 18,000 seeds/acre in dryland. We will just keep praying for rain and hope for the best next year! Ultimately, test this and your other on-farm questions for yourself to know what will work for your farm!
If you’re interested in conducting some seeding rate trials, please let anyone on our UNL On-Farm Research Team know! All our studies are posted on the CropWatch on-farm research page.
What planting rates are you considering for 2013?
On-farm Research
Wow, I’m sorry I haven’t published much the past two months! Much has happened though as we’re in the middle of winter Extension ag programming season! I love this time of year seeing farmers and ag industry reps-and just chatting about what happened last year and speculating about the upcoming season.
Many of you are also attending numerous meetings. You’re gathering information regarding products and production practices. You may be wondering “Will this work on my farm?” Why not go a step further and see for yourself? On-farm research is a great way to test these questions for yourself using your own equipment in your own fields!
UNL Extension has partnered with the Nebraska Corn Board and Nebraska Corn Growers to form the Nebraska On-farm Research Network. There are three main studies we are conducting state-wide: corn population, corn nutrient, and corn irrigation studies…but we are open to helping you design a valid research experiment for your field to test what you would like-and it can be for a crop other than corn.
We have some upcoming opportunities for you to learn more. On February 11 and February 12 from 9:00 a.m.-3:00 p.m. at UNL’s Ag Research and Development Center near Mead and the York Co. Fairgrounds in York respectively, growers who conducted on-farm research in 2012 will be sharing their results; you can also learn more about conducting on-farm research in your own field. There is no charge for the meetings courtesy of the Farm Credit Services of America but we do need an RSVP for meal count and handouts. Please RSVP by calling (402)624-8030 for ARDC or (402)362-5508 for the program in York. I hope to see you at these meetings as well!
JenResources 