Reducing Tillage in Vegetable Crops

This spring and summer our team visited 100 small-scale vegetable farms in Minnesota to do soil health assessments, and one of the key drivers of healthy soil was tillage. Soils with less tillage had better aggregate stability, faster water infiltration, and less compaction. While tillage is harmful in the long-term, it provides short-term benefits that can make growing vegetables easier. This article covers some of the main reasons that farmers till their soil and provides other ways to get the same benefits.

Tillage is the practice of disturbing soil by digging, stirring, or turning. It is commonly used in vegetable farming to loosen compact soils, add residues to the soil, prepare fields for planting, incorporate fertilizers, and manage weeds.

Reducing tillage provides long-term benefits to soil health. Soils that have less tillage tend to:

• Have more stability
• Resist compaction
• Hold more water
• Have less erosion
• Have enhanced biological activity

Reason 1 for tilling: Loosening compact soils

Loosening compact soils is one of the primary reasons that people till their soil. Tillage can be used to create new plots in areas like lawns or pastures. It is also used annually to help loosen soils before planting.

Alternative 1: Cover crops

One of the most important strategies growers can use to manage compact soils is planting deep-rooted cover crops. Cereal rye does an excellent job of loosening compact soils. Other common choices include cover crops with taproots like tillage radish and sugarbeet, or cover crops with very deep root systems like sorghum sudangrass (sometimes called Sudex).

Do not plant cover crops in the same families as your main vegetable crops. This helps to avoid disease and insect pest pressure. For example, planting tillage radish in the fall might be risky if you will plant broccoli in the same field the next year because they are in the same family and experience the same diseases and insect problems.

Alternative 2: Less aggressive tillage implements

Tillage implements like rototillers or moldboard plows cause a lot of soil disturbance. Switching over time to tools that disturb the soil less can help reduce compaction. Light-intensity tillage implements include tools like broad forks and tilthers. Medium-intensity tillage implements that can help loosen compact soil include chisel plows, discs and vertical tillage.

Keep in mind that while tillage aerates soil in the short term, it breaks up beneficial soil aggregates and leads to more compaction in the long-term. Lower and medium intensity tillage implements are better than traditional tillage tools like the moldboard plow. But, they can lead to similar problems if used too often. In some cases, growers find that they need to make multiple passes with these tools to get the benefits they need.

Each farm is different, and the success of these less intensive tillage implements will depend on soil type and other management factors.

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