Crop and Water report 08-18 to 08-24

Weather and crop water use

Reference evapotranspiration (ET) and rain in the Upper Republican NRD was around 1.3 and 0.05 inches, respectively. See attached image for more details on ET and rain data as well as crop growth stages and their water use coefficients for this period.

ET and rain data 08-18 to 08-24

Crop conditions

Western bean cutworm damage on corn
Western bean cutworm damage on corn

Dryland crops in SW Nebraska are showing signs of drought, but are generally in good conditions. My rough estimation on average dryland corn yield this year would be around 110 bu/ac. Irrigated corn and soybean look very good! Relatively lower ET allowed irrigators to catch up with crop water demand. A number of corn fields have high infestations of western bean cutworm with larvae already feeding on ears. Insecticide treatments are not advisable at this point since pest is well protected. If corn is to be planted next year consider Bt-trait that will control (or suppress it) or plan on insecticide application during the season. Western corn rootworm beetles are flying and insecticide application may be applied to prevent battles from laying eggs and reduce next year’s larvae damage. If corn is rotated with some other crop insecticide application is not recommended at this point.

Management checklist for wheat producers:  

1. Control volunteer wheat and weeds in wheat stubble and fallow to preserve moisture and nutrients, reduce the weed seed bank and control disease vectors.

Research from USDA‐ARS, Central Great Plains Research Station in Akron indicates 4-6 bu/ac yield penalty on wheat for each inch of available soil water being reduced at wheat planting.

Nutrients taken up by weeds and volunteer wheat can increase the cost of your fertilizer inputs. Simple calculation for estimating your wheat fertilizer needs based on fertilizer and wheat price, residual soil nutrients and yield goal can be found at UNL Extension website.

Wheat Streak Mosaic Virus (WSMV) disease is transmitted by the wheat curl mite (WCM) and “green bridge” provides host plants for both virus and mite to survive and cause problems next year. Mace is wheat variety tolerant to WSMV and you should consider it if you had a history of WSMV in your field.

Recommendation: Tank-mixtures of glyphosate with 2,4-D or dicamba, or gramoxsone are usually very effective in controlling “green bridge”. Two applications might be necessary in some cases, but avoid applying these chemicals 2 weeks prior to planting to avoid herbicide injury.

volunteer wheat
volunteer wheat

2. Consider buying certified, fungicide-treated seed to prevent yield losses from seed- and soil-borne pathogens and eliminate germination and survival problems that may be associated with planting bin-run seed.

Lover test weights were reported this year from a number of producers that did not sprayed for stripe rust. Wheat leaves that were severely infested with stripe rust fell off prematurely and imposed a stress on wheat crop during the grain filling period. K-state researchers found that planting seed with lower than 55 lbs per bushel may require special attention such as shallower seeding depth, higher seeding rate, adjusting seed blower to blow out “chaffy” seeds, and germination test. For more information click here.

Seed-borne diseases including Black Chaff, Fusarium head scab and ergot observed in this year’s wheat crop. Soil-borne diseases including root, crown and foot rots are common if soil conditions are wet during germination period and yield losses can occur due to poor establishment. Click here for more information.

Recommendation: Plant certified, fungicide treated seed. If using bin-run seed send seed to a lab for germination test or do the germination test yourself by wrapping seeds in wet paper towel for 5-7 days and estimating percent that survived. If germination rates are less than 80% fungicide treatments are highly advisable. For list of fungicide seed treatments click here.

3. Variety selection is critical part of every cropping systems. This doesn’t necessarily mean to select highest yielding variety from the book and expect highest wheat yield in the county. We need to become more familiar with other characteristics such as winter hardiness, disease tolerance, maturity, etc. For example, Byrd is one of the highest yielding varieties commonly planted in SW Nebraska, but it is very susceptible to stripe rust; therefore, you need to be tracking progression of stripe rust throughout the season and be ready to spray preventively. This year $20/ac investment on spraying stripe rust on Byrd made approximately 30 bu/ac yield difference.  For Nebraska Extension Fall Seed Guide click here.

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Crop water use 07-27 to 8-13

Reference evapotranspiration (ET) in the Upper Republican NRD ranged from 4.18 to 5.24 inches in this 17 days period (from 0.25 to 0.31 inches/day), with area to the south and with less rain having larger ET. Two storm came through SW Nebraska on August 5th and August 8th, each carrying from 0.5 to 3.0 inches. Rain really helped all dryland crops as it came at the right time and after good growing conditions we had in June and July. Hopefully the trend will continue to produce outstanding dryland yields for this area.

To more accurately estimate rain and crop water use on your farm, look at the map (attached) provided, obtain weekly reference ET value from location closest to you and multiply that value by crop coefficient provided in the table.

ET and rain data

Crops and Water report 07-21 to 07-27

Weather and crop water use

Reference evapotranspiration (ET) in the Upper Republican NRD ranged from 1.70 inches at north parts of Perkins County to 2.20 inches in south Dundy County; we received between 0 and 1.70 inches in rain. To more accurately estimate rain and crop water use on your farm, look at the map provided, obtain weekly reference ET value from location closest to you and multiply that value by crop coefficient provided in the table.

ET and rain 7-21 to 7-27

Weeds control in wheat stubble

Strip of uncontrolled downy brome next to the wheat stubble will cause problems in the future
Strip of uncontrolled downy brome next to the wheat stubble will cause problems in the future

Time to control weeds in the wheat stubble! New Cropping systems specialist from Panhandle Research and Extension center, Cody Creech, suggested 3 steps to control weeds in wheat stubble: (1) Carefully identify weeds that are present in your field, (2) spray weeds kochia, Palmer pigweed, pricly lettuce, Russian thistle and other tough to control summer annuals with tank-mix of glyphosate, dicamba and/or 2,4-D to prevent seed development (3) monitor for winter annual weeds like rye, marestail and cheetgrass and plan timely herbicide application in fall and early spring. For more information click here.

Corn

Corn is at reproductive growth stage. Adults of Western Bean Cutworm have been emerging in past week and spraying has been done in the area. UNL’s recommended threshold for insecticide application is 5-8% of corn plants have egg masses and/or small larvae.

Western bean cutworm egmass
Western bean cutworm egmass

Other crops

Sunflowers are at V5 to butonization stage. Field peas harvest is done. Soybeans are at R2-R4 growth stage (setting pods). Milo is at booth stage. Potatoes in tuberization stage. Dry beans are at 80%-full cover. Sugarbeets are at full cover.

Crop report July 21

Weather and crop water use

Isolated t-storms delivered from 0.2 to 1.8 inches across Upper Republican NRD. Reference evapotranspiration (ET) losses were 2.0 inches on average. To estimate crop water use on your farm look obtain weekly reference ET value from location closest to you and multiply that value by crop coefficient provided in the table.

ET and rain 7-13 to 7-20
ET and rain 7-13 to 7-20

Wheat

Wheat harvest is 95% done! Dryland yields range from 20 bu/ac to 90 bu/ac. Farmers that had hard winter kill and didn’t spray wheat for stripe rust had lover yield and lower test weight (about 53-55 lbs/bu). Wheat kernels diseased with ergot and/or Fusarium head scab have been observed. Although these did not appear to be a major yield limiting factor wheat can affect marketability of wheat seed. Loads can be rejected at the elevator if 0.05% of wheat kernels have ergot (about 0.5 oz/bu) or if over 1 ppm concentration of DON toxin has been detected in Fusarium-damaged kernels. Setting up your combine to blow out “chaffy” seed take care of this problem.

Ergot in wheat
Ergot in wheat
Wheat kernels infested with Fusarium head scab
Wheat kernels infested with Fusarium head scab

Corn

Corn is at V14 to tasseling growth stage. Adults of Western Bean Cutworm have been emerging in past week. If 5-8% of corn plants have egg masses and/or small larvae, consider an insecticide application either through a center pivot irrigation system of by airplane. It may be beneficial to select an insecticide that controls both spider mites and Western Bean Cutworm as mite populations are increasing in the area. Resistance of Western Bean Cutworm to proteins expressed in transgenic corn has been observed in SW Nebraska. Only the Bt corn hybrids containing Cry1Ftoxin (e.g. Herculex I, Herculex XTRA, SmartStax) are effective in controlling the pest. For more information on Western Bean Cutworm and its management click here.

Other crops

Field peas harvest is in progress; dryland yields of 40 bu/ac have been reported. Soybeans are at R1-R3 growth stage. Milo from V8 to booth. Potatoes are in tuberization stage. Dry beans are at 50-80% cover. Sugarbeets are at full cover.

40 bu field peas harvested from this on-farm research study
40 bu field peas harvested from this on-farm research study

Crop water use 6-29 to 7-6

To estimate crop water use or crop ETc look at the map provided, obtain weekly ET value from location closest to your farm and multiply that value by crop coefficient provided in the table. Assuming your soil has enough moisture on the supply side this is how much water your crop used in a past week (June 29 to July 6). Reference ET values have been around 2.15 inches.

ET and rain 6-29 to 7-6

Crop report July 1

Weather conditions

(1) Septoria leaf blotch, (2) stripe rust, (3) black chaff, (4) Fusarium head blight (scab)
(1) Septoria leaf blotch, (2) stripe rust, (3) black chaff, (4) Fusarium head blight (scab)

It is getting warmer and dryer in SW Nebraska. Last week we received 0 to 0.8 inches of precipitation, while reference evapotranspiration (ET) losses dropped 2 inches. Many farmers are irrigating corn and other crops to build up the soil moisture profile so they can keep up with water demand during the peak of the growing season. Awoid chemigating roads and neighbor fields. Wheat Most of the wheat is at dough stage, but harvest will start next week in some areas! Hard winter kill in some areas, dry early spring and very wet April and May created favorable conditions for diseases that we don’t usually expect in this semi-arid climate to develop to flourish. Many farmers were not ready for it and diseases like black chaff, stripe rust, Fusarium head blight (scab) and Septoria leaf blotch are going to cause severe yield reductions. We learned that knowing varieties you planted is the best way to fight diseases; if variety is susceptible to stripe rust, be ready to spray.

Cultivation was used to control kochia in popcorn
Cultivation was used to control kochia in popcorn

Corn Corn is at V3 to V10 growth stages. Fields reveal the consequences of planting in wet conditions. Restricted root growth due to compacted seed bet is very common. Rootworm injury has been observed in continues corn. Look at which Bt-protein is expressed in your Bt-corn hybrid. If eCry3.1ab, mCry3A or Cry13Ab1 proteins are not expressed in your hybrid chemigate with Capture LFR or Brigade to control larvae of the rootworm. Even though, tillage and cultivation are a big “NO” in this part of the country, popcorn producers started cultivating due to lack of options to control kochia and Plamer amaranth.

PPO herbicide injury in soybean
PPO herbicide injury in soybean

Soybean Soybeans are at V1-V6 growth stage. Time to inspect soybeans for nodulation. Cut nodule in half and if color of tissue is pink, nodules are active and nitrogen fixation is present. Kochia is very hard to control and it’s gaining biomass rapidly with warm weather. Severe herbicide injury has be observed on soybeans in this area. Avoid applying generic herbicides that you haven’t used before at high temperatures to reduce the risk of hearting a crop. Other crops Milo from emergence to V6. Field peas are filling pods. Potatoes are in tuberization stage. Dry beans are at VE-V3 and in good condition. Sugarbeets are at 75% cover, and some insect damage and Cercospora leaf spot is visible on leaves, but no management action is needed at this point.

dry beans at V2
dry beans at V2
field peas filling pods
field peas filling pods
sugarbeeets at 75% cover
sugarbeeets at 75% cover

Crop water use June 22- June 29

To estimate crop water use or crop ETc look at the map provided, obtain weekly ET value from location closest to your farm and multiply that value by crop coefficient provided in the table. Assuming your soil has enough moisture on the supply side this is how much water your crop used in a past week (June 22 to June 29). Reference ET values were around 2.00 inches and similar among 15 locations in Perkins, Chase and Dundy Counties.

Et and rain 6-29