Here’s how rainwater harvesting for agriculture and livestock can play a bigger role in the future for water conservation. Another informative article by Doug Pushard.
Agriculture and ranching consume a substantial amount of potable and pumped water around the country, and to some extent in Northern New Mexico. In some areas of the US, farms and livestock consume up to 60% of overall water use. This water is usually either clean, highly processed potable water or well water pumped from precious underground aquifers. This is not a great use for this water given that a cheaper, better and proven alternative is readily at hand. Rainwater is FREE and sometimes very plentiful even in the arid southwest; it is no wonder its use is growing for agriculture and for ranching purposes. Not only does using rainwater save processing and/or transporting water; it also saves energy and helps the environment (see article on the Energy/Water relationship).
A question I occasionally get from readers is, – “Is rainwater good for plants”. I must admit I take long pause when I get this question. It is as if we have forgotten that our primary water source is the sky. If it were not for rain we would live in a very parched world. My great aunt caught rainwater for use on her summer garden; it has been a source of water for generations for both crops and livestock. My typical response is, – “Would you pour chlorine on your plants?” (Chlorine is used by most water utility companies to purify water before it arrives at your spigot.)
Yes, rainwater is good for your plants. It is naturally clean and in fact requires the addition of minerals to offset its lack thereof. Paul Cross, owner of Charybda certified organic farm in Arroyo Hondo, New Mexico, captures 45,000 gallons of rainwater a year to use in his greenhouses. Rainwater is the only water he uses on his tomatoes that he sells at various venues around New Mexico, including Santa Fe Farmers Market, Taos Farmers Market, Whole Foods and La Montanita Co-op (under the Chef’s Edition label). Cross started his farm on a parcel typical of northern New Mexico — one not blessed with rich soil or abundant water. He quickly learned to use what he had — wide open space, abundant sun and rain. According to Cross, “You only have to get caught outside in one summer monsoon to realize the water is abundant at times and very scarce at others. The trick is to capture it when abundant for use when it is not”. Stored properly and used wisely, he found he could grow an amazing tomato crop using only rainwater.
At Charybda Farms, Cross captures rain off the roofs of both his house and green house, a total of nearly 6,000 square feet. The rainwater is channeled from the roofs to his cisterns. He then uses drip irrigation to judicially water the tomatoes as needed. Any excess water is caught and recycled. Cross is always looking for new ways to make his farm more energy and water efficient, to be sustainable, and yet produce a delicious crop year-round. To offset the lack of minerals in rainwater and to meet the specific mineral requirements for tomatoes, Cross adds the minerals calcium and magnesium to the rainwater. He also adjusts the notoriously soft rainwater to the more acidic pH tomatoes love using only vinegar.
Rainwater can also be used for livestock and in fact is used extensively throughout Texas as a way to augment pumped water and in some cases as a sole source. Although Cross stores his rainwater in cisterns, rainwater for agricultural use is often held in ponds instead of stored in tanks or cisterns. While evaporation is a downside to this approach, it is more than offset by the effectiveness of the ponds in capturing large quantities of rainwater inexpensively.
To create large catchment areas usually required for livestock, rainwater is captured right off the ground with soil or rock being pretreated to quickly shed water without absorbing it. This captured water is typically channeled to a low point for pumping into a cistern. The harvested rainwater is then fed into small troughs filled automatically by float valves to create systems that require little to no maintenance and yet provide livestock water year-round.
The Texas AgriLife Extension Service of Texas A&M University has researched and written extensively on the use of rainwater for livestock (www.agrilifebookstore.org). Billy Kniffen, Water Resource Specialist at the Department of Biological and Agricultural Engineering with the Texas AgriLife Extension Service, states that adding rainwater catchment provides water for existing livestock while attracting other species, making wildlife viewing more enjoyable and hunting leases more valuable, and reducing the cost and maintenance of mechanical pumped systems.
Harvesting rainwater for agriculture and livestock use is expanding just like it is in the residential and commercial markets. Vegetable producers view high quality rainwater as ideal for organic production, and nurseries particularly like this “pure water” in their mist systems, in cooler pads as well as for irrigation. Ranchers and animal owners utilize rainwater to irrigate small areas of pasture temporarily, supplement a windmill or low producing well, or as backup in case a well fails mechanically or runs dry. All these uses, plus it saves energy by eliminating the electricity required to pump and transport water.
Charybda Organic Farms proves it is quite possible to farm using rainwater exclusively and produce a great crop. Cross’ farm uses almost no water pumped or piped from the earth. Using rainwater for agriculture and ranching makes good business sense, and it’s good for the environment. Pumping, cleaning and transporting water consumes vast quantities of energy as well as water. Harvesting rainwater saves energy, reduces pollution, and eliminates the draw on our streams and aquifers. Farms and ranches across the country are doing it — why not you? Please help conserve our most precious resource. The solution starts with each of us doing what we can.