Extension Update from Jenny Rees

Jenny’s REESources-August 21, 2016

UPCOMING EVENTS: 

Aug. 23:  West Central Crop and Water Field Day, http://extension.unl.edu/statewide/westcentral/fieldday/
Aug. 24:  CMDC Late Season Clinic, ARDC near Mead, http://ardc.unl.edu/crop.shtml
Aug. 25:  CMDC Corn/Soy Production School, ARDC near Mead, http://ardc.unl.edu/crop.shtml
Aug. 26-Sept. 5: Nebraska State Fair, Nebraska State Fairgrounds, Fonner Park, Grand Island, NE
Sept. 13-15: Husker Harvest Days, Husker Road, Alda, NE
Sept. 28:  Sustainable Ag Research Education Field Day on Corn Stalk Grazing, US MARC near Clay Center
Nov. 14:  Ag Land Lease Workshop and Flexible Cash Lease Workshop, 4-H Building, York
Dec. 1:  Solar Power in Ag Workshop, 4-H Building, York

Last Irrigation:  With many area corn fields in beginning dent and starch fill, I should have written about last irrigation last week.  You may be wondering how to schedule the last irrigation.  For those of you with watermark sensors or soil moisture sensors, the goal is to use them to determine when the soil profile reaches 60% depletion (for silty-clay soils in our area aim for an average of 160 kpa of all your watermark sensors).  At beginning dent corn you need 5 inches of water to finish the crop to maturity (the NebGuide also says approximately 24 days depending on the year).  Corn at ¼ starch or milk line needs 3.75” (about 19 days) and ½ milk is 2.25” (about 13 days).  Soybeans at the beginning of seed enlargement (R5) need 6.5 inches and at full seed enlargement (R6) need 3.5”.  The UNL NebGuide “Predicting the Last Irrigation of the Season” provides good information on how determine your last irrigation in addition to showing charts on how much water the crop still needs at various growth stages. 

One way to look at this is by the number of days left and use a step down approach…so essentially for approximately 24 days left at beginning dent, increase your average trigger for irrigation over 3-4 weeks.  At beginning dent, if you were allowing your sensors to average 90kpa previously, then aim for an average of 110kpa the first week, 130kpa on the second week, and 150kpa on the third week.  If these triggers are met during the week, you would put on about 1 inch of water.  By going to these numbers, you dry out your soil profile to allow for recharge this fall, winter, and next spring.  In many years but perhaps not this one, it might give you a higher probability for rain in the next couple of weeks. 

Abnormal Ear Development:  I was grateful to Dr. Roger Elmore, Extension Cropping Systems Specialist and Dr. Justin McMehan, new Cropping System Specialist, for joining me in some Clay County fields this past week.  A deeper discussion with photos can be viewed in this week’s CropWatch at http://cropwatch.unl.edu.  Essentially, this is a genetic X environment interaction.  We believe the July 7^th wind event was a major contributor in causing the primary ear of certain racehorse hybrids to be aborted as the wind was a common factor throughout the state.  Most of these fields had minimal greensnap and we hypothesize that the extreme wind may have damaged the meristematic tissue where the primary ear was developing causing abortion of it and thus the various types of ear formation present in those fields.  Companies test hybrids under numerous environments and this year was quite abnormal.  As Roger mentioned, this is only the second time in his life where he’d seen this type of widespread ear development and we all hope we never see it again.  We began with the cool spring followed by high heat in June where the hybrids had fast elongation under irrigation.  July 4^th time-frame turned cool followed by the July 7^th wind event and high heat again during pollination.  We hope the CropWatch article helps explain what is being observed in some fields and we hope it increases awareness for you to check fields now instead of waiting till the combine goes through them.  In general (not related to the abnormal ear development), there is quite a bit of tip back from the heat during pollination and there is some firing of leaves likely due to nitrogen loss from rain events in the spring. 

Emergency Haying (till August 31^st) and Grazing (till September 30^th) of Conservation Reserve Program (CRP) acres has been approved for Adams, Webster, Kearney, and Franklin counties. 

Termination of Land Leases for the upcoming crop year should be conducted by August 31, 2016.  It is recommended that the farmland lease be terminated by Registered Mail™.  This means that the person receiving the letter signs for it, providing evidence that the termination notice was received.  For more information, check out this week’s CropWatch at http://cropwatch.unl.edu.

Lawns:  Summer turf diseases are rampant right now due to warm temperatures and moisture from irrigation. Humid air and warm days followed by nighttime temperatures that cool to the dew point result in surface moisture that favors infection. Preventive fungicide applications are most effective for disease control, but at this point many lawns have active infections. So prevention is too late. Home lawns can often tolerate a low level of damage without justifying the need for fungicide applications. Lawns will recover on their own from leaf spot diseases like dollar spot and brown patch once weather conditions dry out and cool. “Curative” applications may stop a disease outbreak from spreading further, but the damage will have been done. Additionally, higher rates are required for curative applications and these rates are not available for homeowner purchase.  Often environmental conditions suitable for disease infection may subside following the initial outbreak, meaning that a curative application may be completely unnecessary.

Now is also the best time for lawn renovation.  For those who have called asking how to get rid of unwanted other types of grass and weeds in your lawn (other than nutsedge), August is often the type to apply glyphosate to kill those areas and then reseed those areas with desirable grass seed (after the waiting period according to the pesticide label restrictions). This YouTube video explains step by step considerations:  https://www.youtube.com/watch?v=4M1Khr1ENWY.  This YouTube video also does a good job explaining how to bring back a drought-stressed lawn that many of us may have experienced this past year:  https://www.youtube.com/watch?v=CmHBUFK2AcY&feature=youtu.be.  I also really like the publication “Improving Turf in the Fall” as it goes step by step into how a homeowner can do this.  You can find it at:  http://turf.unl.edu/NebGuides/ImprovingTurfinFallPrograms2010A.pdf or we’d be happy to provide it for you at the Extension Office.  You can find all our lawn NebGuides at:   http://turf.unl.edu/turf-fact-sheets-nebguides.