Soil Maintenance and Refurbishment

Dominic Lajoie- Maine Farmer and Andrew Plant- Maine Potato Board

As farmers, at the end of a long growing season when temperatures drop, when crops get harvested and put into storage, and when thoughts (daydreams) stray to traveling to warmer destinations or taking a snowmobile trip, we are often snapped back to the reality of one last thing to do: Put things away for the winter.

All the tools, implements, tractors need to get serviced and put under cover in preparation for next year’s crop. We do it because it’s the right thing to do. They are investments. They cost money. We want them to last as long as possible in order to maximize their financial efficiency. Pick out the greatest investment you have on your farm, and think about how you care for it….. Did you pick land as your investment? If yes, good. If no, here’s why you should. (More specifically, it’s not necessarily the land, but the soil that resides on that land.)

Your land (soil) is the piece of equipment that when properly cared for, won’t depreciate in value, and should grow much more valuable in the future considering future global land and food needs. Often, however, it isn’t considered as the investment it really is; it’s a tool, instrument, implement, piece of equipment that helps you grow your crops. It may not have the single greatest monetary value of the things you own, but it’s the one thing common to producing the crops you make your living from year after year, decade after decade, generation after generation.

Our point? Treat it like your greatest on-farm possession. Consider ways to maintain it, improve it, update its operating system, grease its wheels. At a recent Soil Health Initiative meeting we attended sponsored by the National Potato Council and Soil Health Institute, soil and its health in potato production systems was discussed and defined as a vital, living ecosystem that sustains plants, animals and humans.

Five principals for soil health were discussed at this meeting. We list them below, with ways we think we can fit these into potato production systems.

1. Minimize Soil Disturbance— Every time we till we burn off soil carbon and negatively impact soil physical structure and microbiology.

  • Minimize tillage— One-pass hilling, chemical tillage, improve tillage timing
  •  No-till— Incorporate no-till systems into our crop rotations such as grains, beans, and cover crops

2. Cover Your Soil— Much like we put our equipment and implements under cover for the winter months, we should also do the same for our soils. Essentially, think of this as keeping your soil where it belongs.

  • Spring tillage— consider leaving grain stubble or underseeded crops untilled through the fall and winter. Consider underseed or cover crops that will winter-kill or look at chemically desiccating cover crops in late fall to help with spring breakdown. If wanting to prepare fields for potatoes in the fall, consider putting a winter-killing cover crop on it after it’s prepped.
  • Nurse crop— consider using a nurse crop of a small grain to help hold soil in place after potato planting. The time period between planting and potato emergence and root growth can be a precarious one with the potential to lose a large amount of soil in short period of time. Many farmers in the area have a good luck with broadcasting small grains just ahead of potato planting, and then desiccating them 20-30 days after planting.
  • Cover crop at potato harvest— consider using a small grain to spread 24-48 hours ahead of harvesting potatoes. The harvest activity itself will serve to incorporate the grain and provide a cover to the ground going into the winter months.

3. Maximize Diversity— Diversifying the types of plants your soil sees will help diversify and build the numbers of soil microbial communities your soil will have.

  • Consider growing something new- A general recommendation is to have your rotation include a cool-season broadleaf (potatoes, clovers, canola, mustard) , cool-season grass (small grains, timothy), warm-season broadleaf (bean crops, chickpea, sunflower), and warm-season grass (sorghum sudan, millet).
  • If you can’t fit it into your rotation, consider fitting it into your cover crop. Once you get used to cover cropping, try expanding it to include multiple species or crop types.

4. Keep A Living Root for As Long as Possible— Roots (more-so living than dead) provide the food for microbial communities to live from. Roots leak out nutrients and sugars (exudates) to feed these microbial communities. In turn, they pay us back by helping feed our plants, providing better soil structure, and antagonizing pathogen communities.

  • Again, consider cover crops, ones that don’t winter-kill will do better at this than those that do.
  • Consider rotating to a perennial (timothy, clover, alfalfa etc)

5. Integrate with Livestock— This is the most difficult of the five principals to uphold, but consider now or in the future, the use of spreading manure, compost, or livestock itself on your ground. My guess is that over time this will become more of a feasible thing as the livestock industry looks north and east to expand.