Title: Progress Report on On-farm Evaluation of Forage-stand Rejuvenation Methods to Determine the Most Effective and Profitable Methods for Northern Alberta Producers
Collaborators: Soames Smith (Rycroft) & Bill Smith (Grovedale)
Funding Received from: Alberta Crop Industry Development Fund (ACIDF)
Research Coordinator: Dr. Akim Omokanye, PCBFA
From: Peace Country Beef & Forage Association 2016 Annual Report
Producers’ questions in the Peace on forage-stand rejuvenation methods always include: How much more forage does a reseed produce? How will I gain from forage stand rejuvenation? Where will I see the benefits? What reseeding methods or seeding equipment should I use? How can I reduce soil compaction and improve water infiltration? Can I seed in fall instead of spring? Are there studies comparing emerging new ideas of methods of rejuvenation to already established methods? To answer these questions, this project seeks to examine a dozen methods of rejuvenation of depleted forage stands at two locations in the Peace.
The key results of the project will include how to increase economic returns, how to improve forage quality and how to manage degraded soil with minimal environmental effects. The project is aimed at providing producers with a practical look at potential options and methods to improve the productivity of older forage stands. The different methods will be evaluated using the systems approach, which will examine individual production components (soil & environment, forage, livestock, and economics-cost/benefit analysis) and how these components interact.
There are 2 sites for this project. Site 1 is at Uddersmith Dairy- Soames Smith (organic beef farm), near Rycroft. Site 2 is at Bill Smith’s (conventional beef farm) in Grovedale.
The tests were established using a Randomized Complete Block Design (RCBD) with three (3) replications at each site. Each treatment plot is about 0.25 acres in size making it approximately 10 acres (including gaps between treatment plots and replicates.
2015: Prior to any treatment implementation in 2015 and for baseline data, we took soil samples for soil nutrients and quality at 0-6, 6-12, 12-18 and 18-24” soil depths. We also determined forage yield and quality, plant composition/proportion, and took soil compaction readings as well as water infiltration rate. The treatments for different methods were implemented in 2015.
2016: For this report, 10 methods of pasture rejuvenation (treatments) are being examined for Site 2, while for Site 1, eleven (11) methods of pasture rejuvenation (treatments) are being reported on. In early July 2016, we measured forage yield and quality, and soil health (compaction, infiltration, nutrients, organic matter). Field notes on seeding establishment success were taken.
Site 1: Uddersmith Dairy - Soames Smith (Organic beef farm), Rycroft
The soil pH, organic matter and nutrients (N, P, K & S) as well as carbon and N and their ratios are shown in Table 1. The most obvious impact of some methods of pasture rejuvenation from Table 1 was the significant increases in soil N and P from a few methods.
The results of soil N (nitrate N) in 2016 showed that Bale grazing and Mob grazing had far more soil N (90 - 124 lbs/acre) than other methods (Table 1). Soil N for both Mob Grazing and Bale grazing was far more from 0-6” soil depth than at 6-12” depth (Figure 1). For Plow under, soil N seemed to be higher at 6-12” soil depth than 0-6” depth (Figure 1).
The soil P was highest for the method of pasture rejuvenation that involved Manure + Subsoil in Fall (120 lbs/acre), followed by Mob Grazing (76 lbs/acre) and then Bale Grazing (64 lbs/acre). Generally, soil P was higher at 0-6” than 6-12” depth, particularly higher for Manure + Subsoil in Fall.
The soil K was generally higher at 0-6” depth than 6-12” for all methods of pasture rejuvenation (Figure 3). Plow Under, Mob Grazing, Subsoil in Fall and Manure + Subsoil in Fall appeared to have higher soil K than other methods.
Soil water infiltration was higher for Subsoil in Fall, Bale Grazing, Fall Seeding with Agrowdrill, and Manure + Subsoil in Fall than other methods (Table 2).
Readings of 400 to 500 psi would indicate potential soil compaction. With a compaction reading of 399 PSI for the control, some of the methods of pasture rejuvenation being tested here seemed to have lessened the compaction issue (Table 2). On the other hand, Mob grazing and for some reason Spring seeding with Agrowdrill seemed to increased compaction.
Looking at compaction readings from 0 to 12” in Figure 4, for some reason soil compaction was least improved by Spring seeding with Agrowdrill and Fall seeding with conventional drill. Figure 4 also shows that most methods of pasture rejuvenation showed significant improvement in soil compaction reduction over check.
Forage Dry Matter (DM) Yield
The forage DM yield was highest for Bale grazing (1939 lbs/acre), followed by Spring seeding with Agrowdrill (1533 lbs/acre), Manure + subsoil in Fall (1506 lbs/acre) and then Plow under (1447 lbs/acre) (Table 3). Except for Spring seeding with plotdrill, all methods of pasture rejuvenation improved forage DM over check by 104-177%.
Comparing Subsoil in Fall and Manure + subsoil in Fall with check, it is apparent that both subsoiling and Manure + subsoil in Fall improved forage DM over check. The forage yield improvement over check was higher with Manure + subsoil in Fall than Subsoil in Fall.
Resting a pasture for a year seemed to slightly improve forage DM yield over check, by about 242 lbs/acre. It is important to note that 2015 (when the treatment was rested) was very dry and grasshopper infestation was very high as well, and this probably affected the following year’s forage production.
Site 2: Bill Smith (Conventional Beef Farm), Grovedale
The soil pH, organic matter and nutrients (N, P, K & S), as well as carbon and N and their ratios are shown in Table 4. The most obvious impact of some methods of pasture rejuvenation from Table 4 was the significant increases in soil N and P from a few methods of pasture rejuvenation.
The results of soil surface N (nitrate N) in 2016 showed that Bale grazing had more than tenfold soil N (48 lbs/acre) than other methods (Table 4) and even appeared to be higher at 6-12” soil depth than most methods of pasture rejuvenation (Figure 5).
The soil surface P varied from 12 to 22 lbs/acre (Table 4).
At a soil depth of 0-6”, Bale Grazing had the most soil K(Table 4). Most of the methods tested appeared to have higher soil K in the 6-12” region than Bale grazing (Figure 6). Generally, the soil surface (0-6”) seemed to have higher soil K than deeper depth (6-12”) (Figure 6).
Soil water infiltration rate was higher for Subsoil in Fall, Plow under and Bale Grazing in that order (Table 5). All other methods had similar infiltration rates.
Readings of 400 to 500 psi would indicate potential soil compaction. With compaction readings of 144 PSI for Subsoil in Fall and 268 PSI for Bale grazing, these 2 methods seemed to have the greatest reduction in compaction compared to most other methods, particularly those that showed >400 PSI (Table 5).