Are there plants in your garden that bit the dust long ago? If so, your soil may actually be thanking you. According to blog writers Kelley House and Kate Norvell, both certified professional social scientists, leaving plants in your garden over the winter is a good thing, and it’s something everyone should consider doing on a yearly basis.
The Soil Science Society of America (SSSA) February 15 Soils Matter blog post explains that plant “litter” that remains after a harvest is called “residue.” Leaving the residues in place over the winter instead of pulling them up or tilling them into the soil surface offers these benefits to the soil and your garden:
- Plant residues reduce erosion and the loss of valuable topsoil.
- Having plant residues on the soil surface prevents soil crusting.
- Residual plant material reduces weeds by covering and shading the soil.
- Plant residues provide shade and regulate soil temperature.
- Cooler soil temperatures also aid in the retention of soil moisture, which in turn is favorable for seed germination in the spring and crop growth.
- Crop residues provide micro-habitats that protect and benefit the germinating plant seeds and establishing seedlings.
- Plant residues provide a source of organic matter for the soil.
The concept of leaving plants in your garden over the winter is in line with another growing trend in U.S. agriculture. “No-till farming” — where crops are grown in undisturbed soil, without tillage or plowing — has been on the rise since the 1980s.
While it may seem like a simple concept, it has some important larger-scale connotations. Because plowing and tillage have been major sources of soil erosion around the world (as well as key factors behind the Dust Bowl), leaving soil undisturbed offers numerous environmental benefits. Farmers who began using the no-till approach found that they could conserve water, reduce erosion, and use less fossil fuel and labor to grow crops. Between 1982 and 1997, cropland erosion in the U.S. dropped nearly 40%.
The technique hasn’t caught on in all countries, however. But if it did, the U.N. Environmental Program (UNEP) says we could see big climate benefits. It would lock more carbon in the soil and curtail fossil-fuel use in farm operations. The UNEP estimates that no-tillage operations in the United States have helped avoid 241 million metric tons of carbon-dioxide since the 1970s — the equivalent to the annual emissions of about 50 million cars.
In a report, the UNEP argues that governments will have to step in to encourage the practice to get it to spread, either by offering research and training or by providing financial support.