By Sonia Howlett, VT Agency of Agriculture, Food & Markets
As the climate continues to warm, our weather is expected to become more extreme and erratic. This will include periods of heavier rainfall followed by longer periods of drier weather. Many Vermont communities have already experienced just how devastating these extreme weather events can be: Vermont has now been hit with ‘historic’ flooding two years in a row. While climate experts certainly don’t expect Vermont will experience flood events like these every year going forward, they do expect that we will experience them at a greater frequency than we did in the past. Cropland and vegetable fields are particularly vulnerable to these extreme weather events.
As we face this changing – and challenging – reality, farmers are having to make decisions on how to manage their land so that it has the best shot to remain productive even through the wetter or drier conditions which are becoming increasingly frequent. Developing this ability to better withstand the increasingly extreme weather events associated with climate change is called “building climate resilience”. Fortunately, many management-related “climate resilient” practices are likely already familiar to you – you might know them as “conservation practices”, or “soil health practices”.
Generally speaking, the following principles can increase a crop field or farm’s resilience to extreme weather:
- Keep roots in the ground (preferably living ones). Roots provide physical stability and support to resist erosion in wet conditions and retain nutrients as the weather fluctuates.
- Keep the ground covered. Bare or tilled ground is prone to rapid drying in drought conditions and erosion in wet conditions.
- Increase diversity. Increased diversity of plants and microorganisms has a lot of wide-ranging benefits for soil health. But at its most basic, know that in extreme conditions some of your plant species will be set back or die so if you have more diversity in your plants/crops, there is a higher likelihood that some of the species will survive and be harvestable.
Some management practices to consider:
Seed down crop fields – Fields in perennial vegetation (e.g., hay) are less vulnerable to flooding and erosion damage than fields in annual crops. Consider permanently seeding down fields (or parts of fields) where you consistently experience excessive saturation and/or high levels of erosion or washouts.
Incorporate perennial rotations into crop systems – Having living perennial roots in the ground for a few years can significantly increase soil health and increase soil aggregation – research shows that these soil health benefits persist even after a few seasons of annual cropping. UVM researchers have found that in forage management systems, a rotation of 4 years hay and 6 years corn (using reduced till and cover cropping) is a great way to promote environmental benefits, without sacrificing yield or forage quality.
Plant cover crops – In vigorous cover crops, the root systems help keep soil in place and the leaves protect the ground surface. Cover crops also take up fall-applied nutrients and make them available to the cash crop in the spring. They can also help manage soil moisture. Ensure that you plant cover crops early enough for them to establish well in the fall to maximize these benefits. Multi-species cover crops are even better at increasing resilience because they have increased plant diversity.
Use no till or reduced tillage – Tilling breaks up soil structure and increases the risk of erosion from wind and rain. It can also limit a soil’s ability to infiltrate and hold water. Minimizing tillage, especially when combined with cover cropping or crop rotations, can significantly decrease risk of erosion on fields where you grow annual crops and help manage soil moisture.
Plant and manage for diverse species in hayfields & pastures – Some forage species like it hotter and drier, other species do well in cooler, wetter conditions. Having a diversity of species in your hayfields and pastures can help you hedge your bets, so that you can get a reasonable harvest in a variety of weather conditions. Ensure you are managing for a diversity of grasses, legumes and forbs and consider reseeding or renovating perennial hay/pasture systems if needed.
Raise the mower bar – Cutting perennials higher has many practical non-climate benefits, from increasing the digestibility of the feed, to reducing equipment wear, to improving regrowth. Always leave at least 4 inches of residual vegetation when harvesting. With regards to climate resilience, mowing higher also leaves the soil more covered, which will help reduce excessive drying or cracking in dry conditions, speed the transpiration of excess water in wet conditions, and leave the plants healthier so that they are better able to withstand unideal conditions.
Reducing your risk of negative impacts from extreme weather will help your bottom line in the medium and long term, so these practices may pay for themselves. That said, these practices also help protect your neighboring communities, so they serve the public good. Because of that, you can find funding for many of these conservation practices through payment programs from the federal United States Department of Agriculture Natural Resources Conservation Service (USDA NRCS) or the Vermont Agency of Agriculture, Food and Markets (VAAFM). Contact your local conservation district at https://www.vacd.org/contact-nrcds/ to be directed to the programs that will work best for your farm.