Coming Events
June 19, 2012 – 7:00 p.m. – PQA Plus Webinar, Extension Office, York
July 12, 2012 – 9:30 a.m. – Herbicide Resistant Weed Management Field Day, David City
Cropping Update
It was nice to get about .75†of rain in a couple of events, could have always used more and I know some areas had considerably more rain than that? We still have some chances the next few days, so only time will tell. The ETgages that I’ve been monitoring dropped between 1.60 – 1.70″ for the week, less than the 2+†we already had a few times this season! The early planted corn field I’m monitoring is in the 10 leaf stage, so the crop coefficient is .69, so for the week we used between 1.10″ or lost just a little ground for the week considering the rainfall we received. To get that estimated crop water use we simply multiplying the crop coefficient for the current stage of growth by the ETgage drop for the week!
The Watermark sensors readings in one of the early fields I’m monitoring averaged 84 at 1’, 60 at 2’, and 20 at 3’ and with an average reading of 72 in the top feet which is what we monitor until tassel time! So we’ve used about 1.20†of water at the current time! The readings in the top two feet at the corn grower plot are averaging 83 at the current time so we’ve used about 1.5â€. I know several producers may be making a pass now that we’ve used over an inch just to make that first pass and break down the stalks for the first time. Hopefully we’ll get a little more rain on Tuesday or Wednesday?
I along with Suat Irmak prepared an article for CropWatch (http://cropwatch.unl.edu) and compared ETgage reference ETs the past few weeks at a York site compared to readings from last season. These numbers can be seen in the table below:
Date 2012 Weekly Change Crop Stage Crop ET
6/11-6/18 1.70 V10 1.17â€
6/4-6/11 2.15 V9 1.30â€
5/28-6/4 1.35 V7 .58â€
5/21-5/28 2.3 V6 .80â€
5/14-5/21 2.60 V5 .70â€
5/7-5/14 2.05 V3 .29â€
Date 2011
6/17-6/24 1.15 V8 .59â€
6/10-6/17 1.30 V6 .46â€
6/3-6/10 2.35 V4 .42â€
5/27-6/3 1.30 V4 .23â€
5/20-5/27 .85 V2 .08â€
5/13-5/20 0.70 V2 .07â€
I guess the take home message is that no two years in Nebraska are the same, so we cannot assume that the crop water use will be the same each year. Producers should use equipment to estimate both Crop ET as well as monitor the soil water status in a given year for more effective in-season water management.
Suat Irmak shared that since ETref is not limited by water availability or plant function, ETref depends on the ability of the environment to extract water from the surface. As such ETref varies significantly throughout the year and growing season as a function of climate as described in the UNL Extension Publication Magnitude and Trends of Reference Evapotranspiration Rates in South Central Nebraska (EC765) available at: http://www.ianrpubs.unl.edu/epublic/live/ec765/build/ec765.pdf.
We often think what happening in our location is what is happening everywhere and that is definitely not the case in Nebraska! ETref varies significantly across the state of Nebraska as climate varies significantly from the eastern to western edge of the state. Further information about reference ET and the variability of climate and ET from one year to another across Nebraska can be found at: http://www.ianrpubs.unl.edu/epublic/live/g1994/build/g1994.pdf http://www.ianrpubs.unl.edu/epublic/live/ec733/build/ec733.pdf
I hope you’ll check these publication out as well as visit our ETgage site at: http://water.unl.edu/nawmn and the complete CropWatch article.
Herbicide Resistant Weed Management Field Day
Our UNL Weed Science Extension Specialists and Educators have put together a field day July 12th in the David City area to discuss limiting the development and spread of herbicide-resistant weeds. Guest speaker will be Jason Norsworthy, associate professor in the University of Arkansas Department of Crop, Soil, and Environmental Sciences. Norsworthy, a national speaker on the problem of herbicide resistance, will address how glyphosate-resistant weeds are changing agriculture in the southern U.S. and what that may mean for weed control in the northern Great Plains.
The program will begin with registration at 9 a.m., a welcome, and tours beginning at 9:30 a.m. The keynote speaker will be during the noon hour, with the program expected to end by 1:30 p.m. The event is free but preregistration is required by July 6 so plans can be made for the complimentary meal, teaching resources, and tour logistics. Register online at http://agronomy.unl.edu/weedresistmgt
Topics include:
Glyphosate Dose Response. See how resistant weeds respond to increasing rates of glyphosate.
Management Systems. Study various herbicide programs and their effectiveness at controlling a glyphosate-resistant weed population.
Liberty Link Soybean. See how Liberty Link Systems can be used to sustainably manage weeds.
Dicamba-Resistant Soybean. View demonstrations of how dicamba-resistant soybean can provide another post-emergence tool for weed management.
Carrier Rate. See the impact of carrier rate on several herbicides. This stop will also address the importance of effective herbicide applications to manage the development of weed resistance.
This program is sponsored by UNL Extension and the Nebraska Soybean Board. Directions to the David City location: From Hwy 15 in David City, turn west on East A St., then continue west for 2 blocks and look for the UNL field signs. It should be a great session, I hope you’ll plan to attend!
Yard & Garden
The ETgage in front of our office with a #30 grass cover dropped 1.30″ this past week! So for the week, we averaged .18″ per day! The good news, I received .78†of rain!
How’s your garden doing? We the early nice weather a planted several of my veggies earlier than normal and I’m now harvesting the fruits of my labors! I’ve picked my first picking of snap beans and have picked several kohlrabi as well broccoli, cauliflower and cabbage. My snap peas are finished and I’ve even harvest a couple zucchini.
It important to control cucumber beetles on your vine crops by making regular applications of recommended insecticides. I also apply fungicides regularly early in the season to control leaf spot disease on tomatoes. For the latest horticulture updates, check out our Environmental Homepage: http://environment.unl.edu/.
