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Drought Stressed Alfalfa and Nutrient Deficiency
Agronomy question asked by Travis in Ballard County one year ago.
We haven't had much rain in the past month and a half -- and have only gotten one measurable rainfall in September, which yielded only 0.27"; this field is not irrigated (unfortunate, for right now).
It has been 35 days since the last harvest, and the alfalfa is on average 10" tall. This field was planted in the fall of 2018 and overseeded in the spring of 2019.
Are the visual signs purely that of drought stress?
I have not taken tissue samples to send off -- as I am thinking it's just due to the drought.
4 Answers Posted
Whilst there is a very visible yellowing effect seen in the images, there is also reddening of the stems and leaves. According to Alfalfa Analyst (see https://www.alfalfa.org/pdf/AlfalfaAnalyst.pdf) this is symptomatic of a boron deficiency, which is also noted as being more readily seen in dry periods such as now.
If needed, I can take a tissue sample to confirm.
During the previous harvests, I would foliar apply boron -- however, I did not do that after the most recent 4th cutting. Most recent soil samples have shown trace to low levels of boron (< 0.5 lbs/ac), and none has been applied other than foliar.
Possibly more to the complete story, but it is seeming like boron deficiency & drought are at the top of the list.
The field did not improve with a somewhat significant rainfall. I have collected leaves and soil samples to send to the lab for analysis -- attached are closeup pictures of the leaves after collection. An external agronomist still believes that it is an issue caused by low calcium, zinc, nitrogen, and boron.
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