Soil erosion is a common problem: one that can greatly damage a farm. Sustainable options are often the solution, allowing the farm to repair eroded soil and remain profitable. However, this isn’t easily done. It is an incremental process that can be time consuming, depending on the level of damage.
Gullies are a dangerous and expensive phenomena, hazardous for wildlife, livestock, and farm workers alike. They collect and move water away from where it is most needed, in addition to moving nutritious top soil desperately needed by plant life. In most cases, gullies will continue to grow unless actively prevented.
Gullies are formed when enough surface water concentrates in a flow line amid inadequate groundcover, resulting in the scouring of soil until a deeper channel is formed. Once this occurs, gullies can spread both down and upslope. Severe instances of gully erosion usually occur due to rainfall from storms and cyclones. The issue is likely to worsen as climate change results in more frequent severe weather events.
Repairing gullies must be done in phases, depending on the severity and the cost of repairs.
-Diverting surface water from the gullies is an essential first step. Water moving to the gully should be diverted or stopped completely in order to continue the repair process. This can be done in several ways, including diverting the water to a stable waterway with a safe disposal area.
-Stabilising the eroding gully head is the next step you should take, since not all gullies erode further than at the head itself. An actively eroding gully head will require a drop structure, which can be made from a concrete flume, sandbags or gabions. Gullies in dispersive soils will require additional management. The key focus here is to keep the walls of the gullies intact.
First and foremost, familiarise yourself with the safety precautions needed to use heavy machinery. Machinery needed to manage a gully can be hazardous to yourself and the soil beneath you if used improperly.
Graders are used to move large volumes of soil laterally when repairing long gullies. Bulldozers are more suited to large and complex gully head erosion. Graders or bulldozer operations should begin by deep-ripping the gully shoulders to a distance and depth depending on the depth of the gully and optimal batter length. Similar rules apply here as for opening drains.
One of the best ways to prevent future problems with your soil is to treat the topsoil portion of the gully with care. This is especially crucial when the subsoil is infertile or dispersive.
If long stretches of gully are to be filled, it is best to split the gully repair into sections: spreading the topsoil from new areas onto areas that are previously filled. This minimises the distance required for the topsoil to be transported. Topsoil should also be pushed to the head of the gully, to later be spread on the gully centre.
Repairing gullies is an essential tool for farmers, a skill you’ll need in order to combat soil erosion.