Written by: Akim Omokanye,
Location: High Prairie
With Collaboration from: Kelvin and Marianne Krahn (Producers, High Prairie)
From: Peace Country Beef & Forage Association 2019 Annual Report
Stock density is the number of animals or animal live weight assigned to a specific pasture area for a specific time period. Stock density is a very powerful tool to manage grassland resources (i.e. improve utilization, reduce spot grazing/selectivity, control competition, manure distribution, produce seed/soil contact, open up a sward for over-seeding.) The cows would usually be moved a few times a day, on multiple days in order to stimulate soil biology and to control prolific weeds. Cattle would primarily consume weeds along with grazing perennial forages that were growing sporadically throughout the farm.
Objectives: To assess the influence of high stock density grazing and a year of pasture rest on soil health improvement, plant diversity and forage production compared to a control paddock, which had normal grazing pressure.
Sites: Marianne & Kelvin Krahn's farm, near High Prairie
An existing pasture is being used for the project.
The following 3 treatments are being tested:
1. High stock density grazing with yearlings, which was about 150,000 lbs/acre. After the high stock grazing, the paddock was left to rest for the remaining part of the year
2. A year of pasture rest - No grazing was carried out through the year.
3. Control (normal grazing practice by the collaborating producer to be followed).
Each treatment is 1 acre in size.
The project commenced on June 25, 2019.
The following measurements will be carried out annually (baseline data in 2019 and then follow up in 2020 and 2021) before grazing commenced every year:
1. Surface soil water infiltration (0-6”)
2. Compaction from 0-12”
3. Soil bulk density from 0-6” and 6-12”
4. Soil sampling from 0-6” for chemical analysis (e.g. pH, CEC, organic matter, N, P, K, S) at A&L lab
5. Soil sampling from 0-3 & 3-6” for soil health indicators at CARA’s lab in Oyen
6. Forage yield & quality including NDF digestibility at 24 & 48 hrs
7. Forage botanical composition (% of grass, legumes and weeds in the paddocks)
8. NDVI reading to monitor pasture health (in years 2 and 3 only)
The following plant types were identified across the entire sites being used for the project: grasses (timothy, fescue), grass-like plants (sedges), legumes (clovers), others including forbs and shrubs (dandelions, yarrow, horse tail, Rose brush, straw berry).
Another set of measurements will take place in the spring of 2020.
Preliminary results are available in the 2020 Annual Report and will be uploaded to this blog at a later date.