Crop and Water report 08-25 to 08-31

It has been three weeks since we had our last rain in SW Nebraska and we are seeing all dryland crops showing signs of drought. Reference evapotranspiration (ET) in the Upper Republican NRD ranged from 1.6 inches in Perkins Co to 2.9 inches in SW Dundy Co. This means that crops in SW Dundy Co used about 1.5 inches of water more than in Perkins Co. See 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 08-25 to 08-31

According to US Drought monitor none of the Counties in SW Nebraska are in abnormal drought, which can means that these conditions are (believe it or not) normal in SW Nebraska this time of the year. According to 30-year weather data, average August precipitation and ET are 2.50 and 9 inches, respectively. This means that the area had the August weather conditions in very close proximity to long term average.

We had very good growing conditions in May, June, July and August, so crops used all that water and heat to produce large biomass and increase yield potential. Rain is much needed to keep up with high water demands during the grain filling period in September, otherwise we will have to be satisfied with the mediocre dryland yields at the end of the year.

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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

Crop report June 18

Weather conditions

About 1 to 1.5 of precipitation has been received in past week. Nitrogen leaching is a concern! About 50-70 lbs/ac of nitrogen has been found in 3rd and 4th foot of soil profile that is probably not going to be taken up by the crop. Taking a soil test is recommended to determine how much nitrogen has been lost and make corrections on your in-season nitrogen management plan.

Hail damage causing yield loss due to stand reduction

Storm carrying 1 inch of precipitation and pea size hail came across areas of Perkins and Chase on June 16. Assess hail damage to the crop before making replant decisions.

Corn plants without damaged growing point will recover with minor yield losses. In corn, growing point is under the soil surface until V5 to V6 stage; thus, protected from hail injury. If you have corn at >V5 knife to inspect the condition of growing point to accurately determine stand reduction.

Soybean has growing point at the tip of the plant, therefore small (V1-V3) soybean plants will not be able to recover after hail damage if growing point is damaged. Larger soybeans may be able to continue growing from semi-dormant axillary buds located inside the leaf axils at first 2 nodes when top of the main stem is cut-off.

Check UNL charts for determining yield loss due to stand reduction for corn, soybean and sorghum.

Wheat

Wheat kernel at watery consistency
Wheat kernel at watery consistency

Wheat started filling grain. Kernels are in between watery consistency to milky ripe. With moisture and we had in past month it has been a paradise for spread of diseases, especially in dryland corners that didn’t received fungicide treatment. Leaves are often covered less than 50% with green healthy tissue. Good news are that this year we had enough moisture to make 100 bu dryland wheat (if rain patterns continue), which will overweight some yield loss coming from diseases and hopefully bring it to above long-term average.

Other crops

Corn growth stages range from emergence to V7. Milo from emergence to V4. Soybeans planting is 90% done and V2-V3 soybeans are found in the area. Field peas and flowering and grew about a foot in past week, potatoes are also flowering and in excellent condition, sugarbeets are at 50% cover.

Sugarbeets at 50% cover
Sugarbeets at 50% cover
Soybean at V2
Soybean at V2