Guidelines for Creating & Maintaining Irrigated Pastures
By Gale Jirik
Mosquitoes are a pest to humans and livestock (can cause a reduction in horse & cattle weight), and more importantly, can transmit disease to humans and livestock. I have put together the following guidelines to aid property owners in proper water management; giving ranchers the highest yield of grass for grazing while reducing or eliminating mosquito production in the pastures.
1. Prepare land properly for irrigation and drainage before a crop (grass) is planted. This includes grading and leveling pastures with slope from the head ditch to the tail ditch, if flood irrigating. If using sprinkler systems, the pasture should be leveled. Construct head ditches and tail ditches to the proper size to handle the flow of water needed to irrigate the pasture in 24 hours. Install permanent water control structures so that water can be turned on or off quickly. Design the pasture to exclude livestock from the head and tail ditches and levies.
2. Existing pastures with poor drainage may require releveling and/or grading to the proper slope.
3. Head and tail ditches require regular maintenance.
4. Culverts need to be maintained regularly.
5. Apply only sufficient water to wet the soil to the depth of plant roots.
6. Irrigate pastures for only 24 hours. If you irrigate for longer than 24 hours it is detrimental to grass growth and causes increased mosquito production. If you have standing water on your pasture for longer than 3 days, immediate action needs to be taken to correct the problem (repair the pasture, apply mosquito control products, or cease irrigation).
7. Irrigate only as often as needed to maintain adequate soil moisture. Irrigating at intervals of 10 days or longer may be sufficient.
8. Do not graze pastures until irrigation water has completely run off the field and the surface is dry enough to prevent deep hoof prints.
9. Divide large pastures into smaller fields for animal rotation and more efficient irrigation management.
10. Clip pastures occasionally to reduce weed and less palatable plant growth, thereby permitting more rapid water movement.
11. Graze uniformly and completely, but not below 2-4 inch stubble.
12. Irrigate immediately after grazing.
13. Allow a 20-30 day recovery interval.
14. If possible, keep livestock out of head ditches, tail ditches, and off levies.
15. If there is a local mosquito control agency, coordinate irrigation with that agency.
16. If there is no local mosquito control agency, there are pesticides that are non-toxic to livestock that can be used to control mosquito breeding.
Land owners who irrigate properly will reap benefits of optimum grass growth and their neighbors will thank them for not producing mosquitoes. If you would like more information on irrigated pastures contact your local agriculture department or farm advisor. These guidelines are for the purpose of aiding property owners in creating and managing irrigated pastures. They are not all inclusive and they do not exempt property owners from their responsibility for the production of mosquitoes breeding on their property.
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