Protecting
the Future: Mitigating Spring Soil Erosion
This spring in the Annapolis Valley,
erratic and heavy rainfall events have highlighted a critical vulnerability in
our farming systems: soil erosion, particularly on our sloped landscapes. As a
grower, watching topsoil wash away is watching your farm's future productivity
disappear. Topsoil contains the highest concentration of organic matter and
nutrients; once it is gone, your soil becomes less fertile, leading to an
increased dependency on fertilizers and, eventually, the permanent loss of land
value.
The Evidence: A Side-by-Side Lesson
The visual evidence in our fields
right now is undeniable. In the Soil erosion photos (soil erosion 1.jpg, soil
erosion 2.jpg), we see a sloped field that was prepared for planting. Without
cover, the kinetic energy of raindrops detaches soil particles, leading to
massive rill erosion.
In contrast, the Protecting soil
erosion photo (Protecting soil.jpg) shows the second half of the same field
protected by Winter Rye. The rye provides a physical canopy to break the impact
of raindrops, while the root architecture anchors the soil, effectively
eliminating visible erosion.
Because Winter Rye is a perennial-like
crop that requires termination in the spring, growers looking for a
low-maintenance alternative can plant annual species in the fall, such as:
- Radishes and Oats: These species are winter killed,
meaning they do not require termination in the spring.
- Biomass Benefits: If planted in August or early
September, these crops can grow 1 to 3 feet tall, providing significant
biomass residue and roots to protect against erosion.
Cover crops and Nutrient Cycling: In
addition to erosion control, these cover crops assist in nutrient cycling and
overall soil health.
Strategies
for High-Slope and Spring Management
To preserve our soil, we must
implement specific Best Management Practices (BMPs), especially when dealing
with steep topography:
- Contour Farming and Bed Orientation: Where high slopes exist,
utilize contour farming. Ensure beds are oriented perpendicular to the
slope rather than running up and down the hill to create "mini dams"
that slow runoff and encourage infiltration.
- Living "Walkways" and Wheel Tracks: Consider planting winter
rye or other resilient crops between beds. These green strips act as
protected lanes for foot traffic or machinery, preventing compaction of
the primary growing ground.
- Optimizing the Spring Preparation Window: We recognize that ground
must eventually be prepared for planting, but the goal is to minimize the
time soil sits bare. Do not prepare ground too far in advance; prepared
soil is more prone to erosion and takes longer to dry out after rain.
- Reducing Tillage Intensity: Every tillage pass breaks
down soil aggregates and destroys macropores. Over time, frequent tillage
leads to surface crusting and compaction, which further accelerates
erosion.
The Science of Stability: Soil aggregate stability is
maintained by organic "glues" and fungal hyphae. Tillage mechanically
disrupts these bonds, leaving soil particles easily transported by water
Even if your fields are not on a slope, integrating cover
crops into your cropping system provides numerous advantages beyond erosion
control. These crops are essential for building organic soil matter, improving
nutrient cycling, and enhancing the overall biological resilience of your farm.
By maintaining living roots in the ground as often as possible, you promote
better soil structure and water infiltration, ensuring your land remains
productive and healthy regardless of the topography.
Manphool
Fageria, PhD, P.Ag.
Vegetable
Specialist | Agricultural
Services
Perennia Food
and Agriculture Corporation
Email mfageria@perennia.ca
Mobile 902-890-7716
6-28 Aberdeen Street,
Kentville, NS B4N 2N1