Drought impacts on crops and livestock discussed

While the wind has been atrocious in March the moisture was scarce. You can say that from about July of 2020 to today, total moisture is significantly low.  The drought conditions and the potential continuation of lower than normal moisture in the future was the discussion at the Great Northern Wednesday March 31, 2020.

Extension Agent Marko Manoukian recently took 20 soil moisture samples with the Paul Brown (developed by Dr. Paul Brown Soil Spiciest with Montana State University in 1981) probe and found the probe would go in the stubble and winter wheat fields 17 inches.  If every foot of soil represents about 1.5 inches of moisture, then there is 2 inches of stored soil moisture in farm ground.  Paul Brown also created precipitation probability maps for Montana.  In our area we have a 70% chance of receive 4 inches of moisture during the growing season. 

Dr. Kent McVey, Montana State University Crop Specialist has updated information developed by Brown from 1981.  He created a table of yields for crops grown in Montana.  In our example, if you add stored soil moisture and precipitation probability the total expected moisture is 6 inches for crops in 2021.  You can multiply this figure by the seeds per inches of moisture (Table 1), to estimate your potential yield.

Table 1. Crop water productivity (lb/ac/in) for selected crops from the Northern Great Plains.

Dividing this number by 60 pound per bushel of wheat you find the spring wheat and winter wheat yields will be about 21.6 bu/acres and 23.6 bu/acres, respectively.

So when will it rain? For planting it would greatly help to have some moisture to germinate weeds and improve germination after planting. Dry seed decay can be a concern given the current drought conditions. This disease is caused by several soil-borne fungi and occurs when seed is planted in dry seedbeds without sufficient moisture to initiate germination and support seedling establishment. Most fungicide seed treat products can protect against dry seed decay and maintain efficacy for two to three weeks after planting. The longer seed lies dormant in the soil, the more vulnerable it will become to attacks by insect pest and pathogens.

Dr. Megan Van Emon, Extension Beef Cattle Specialist at Montana State University, met with a group of livestock producers that will face similar challenges with the low moisture outlook. Developing a drought management plan can assist producers when to make critical decisions. If grass in limiting now and into the summer, producers may need to consider early weaning their calves. Van Emon recommended weaning no earlier than 80 days of age. If this decision is necessary, calves will have to be provided a high-quality diet with 14% crude protein and 60% energy. Early weaning your calves increases labor, facility costs, and feed costs. It will be necessary to get calves to drink clean water also. Health considerations like pre-conditioning your calves before early weaning should be discussed with your veterinarian.

Producers may need to think of culling more severely during drought. Old cows and extra bulls are two categories to consider. Additionally, heifer calves that are not productive may also be culled. Reducing livestock forage demand may assist operators in lengthening the grazing season and reduce the reliance on additional feeds. None of these decisions are easy but balancing forage supply with livestock demand is critical during drought times.

Van Emon provided participants with a hard-copy drought management resource. If you would like a copy of this handout, please contact the Extension Office.