Excessive tillage occurs on most farms, and is a common tool used to grow vegetables. Ploughing, harrowing, cultipacking, bed-formation and cultivating are all common practises. Unfortunately, these methods are damaging to the soil, especially in the long-term. There are ways to reduce damage, however. Sustainable farmers should be aware of alternatives, and how they can be implemented in an organised, cost-efficient way.
There are a few common ways to reduce tillage. Implementing some or all of these practises will ensure that your soil improves over time. Alternative methods include:
– Using chisel plough shanks, subsoilers or zone-tillers to loosen the soil up before planting. These are common substitutes for ploughing.
-Using summer crops as a cover crop to make your soil better suited for planting throughout the rest of the year.
– Mowing crop residue as opposed to disking.
-Using deep rooted plants to make the soil more robust and easier to use. Radish is a common example.
-Using special, no-till drills.
Deep zone tillage–also known as vertical tillage–is a promising and versatile method to approach soil issues. The method requires you to have access to pre-existing thick blankets of plants. Using a lead coulter, cut through the killed-cover crop residue, followed by use of a deep shank or subsoiler to break up the plough-pan. Finally, use a pair of fluted coulters and a rolling basket to prepare a narrow seedbed, to help break up soil clods.
The deep shanks are mounted onto a hinged frame, which allows the shanks to rise out of the ground when they encounter large rocks or ledge, while spring resets push the shanks back down into position after passing over the obstacle. Additional coulters are mounted on the planter in front of the planting shoes, to remove excess residue and stones. This provides finished seedbeds.
Strip-tillage is yet another alternative that reduces tillage and thus reduces overall damage to soil. The method is also known as shallow zone tillage and is similar to deep zone tillage, but minus the subsoiling shank to break up the plough pan. The implement has two or three closely spaced coulters and a rolling basket, used to prepare and smooth a narrow seedbed through the surface residue. Cover crops are the key to this system’s success: spring-planted oats and field peas are recommended.
In the end, one can also opt to simply use no tillage at all. No tillage planters use double-disk openers and closing wheels to create and close the seed furrow in unworked soil. These planters rely on down-pressure springs and/or extra weights, to assure that the seed furrow can be created even in the case of dry or compacted soil. This approach is particularly useful when planting late vegetables, or after the soil has been warmed by the use of cover crops.
Tillage is a common and time-honoured practise, but also a damaging one. Fortunately, efforts can be made to mitigate its effects, or eliminate the use of tillage altogether.