Author: Maud Powell, Small Farms Program, Oregon State University
Publish Date: Spring 2014
Last month, Governor Kitzhaber declared drought emergencies for four counties in Southern Oregon. As of this week, most of the state is considered to be in either a moderate or severe state of drought by the United State Drought Monitor. Farmers across Oregon are planning for a year with less than ideal irrigation conditions. Those farmers that rely on water from creeks or rivers face greater challenges than those who irrigate from reservoirs. Even if we continue to receive rain this spring, the lack of an adequate snowpack will cause shortages in many watersheds.
Most growers already have their farm plan set for the year and have considered the effects of drought for the upcoming season. Following is a list of ways to help mitigate the effects of drought for the coming year, along with some ideas about how to make a farm more drought-proof over the long haul.
1. Take a look at all types of irrigation systems that may be appropriate for you operation and pick the one that will conserve the most water. In many cases, this may be drip irrigation. Research has shown that drip tape uses 30-50% less water than overhead irrigation.
2. Build a water storage system that holds water for use during irrigation season. Contact your local Watermaster to find out the legalities of building ponds on your farm. Storage tanks that collect rainwater from rooftops can also provide reserve water.
3. Understand the water scheduling needs of your crops. Many farmers tend to overwater, so make sure you are watering at the most appropriate intervals for your crops. For example, onions and beans will take better advantage of more frequent waterings at shorter durations.
4. Store water in ditches along fields.
5. Install measurement devices that track your water use.
6. If possible, utilize water from deep aquifers instead of surface water.
7. Leave crop residue your field (conservation tillage) to improve the water-holding capacity of your soil and reduce evaporation and erosion.
8. Use conservation practices that reduce runoff and encourage the infiltration of water into the soil.
9. Closely monitor soil moisture and irrigate accordingly.
10. Maintain and establish riparian buffers, filter strips, grassed waterways, and other types of conservation buffers near streams and other sources of water.
11. Consider plowing with a subsoiler, ripper or Keyline plough that will increase water-holding capacity of soil and help to build topsoil.
12. Reduce the amount and depth of tillage. Moisture loss increases with both the number of passes and the depth of tillage.
13. Increase the organic matter in your soil through the application of compost, growing and incorporating cover crops into your soil, and growing green manure crops. Soils with more organic matter have a great water-holding capacity.
14. Plant species and varieties of crops that withstand dryness, hold water, and reduce the need for irrigation. Melons, tomatoes, squash and beans are better suited to dry conditions, while lettuce, brassicas and corn rely on moister conditions to thrive. Consider front-loading early-season crops. Some farmers are planting more early successions and waiting to see if they have enough water to plant fall and winter crops.
15. Mulch with straw or cardboard. Mulching with organic materials may not be feasible on a large scale, but can be highly effective for smaller plantings. Larger farms use black plastic mulch, laid out with a tractor, to manage weeds and retain soil moisture.