Tulare County’s Dairy Technology Cluster

Most of the water used by dairies is pumped from private groundwater wells. Since withdrawals from private groundwater wells have historically not been monitored or metered, the exact amount of water used by dairies is not known.

Since the dairy industry is known to be a very large user of water, extensive research is being conducted throughout the U.S. and other countries to understand which water (potable, rainwater, recycled or gray water) is being used for which functions, and where fresh water withdrawals can be reduced.

 

Figure 12. Primary Water Uses in Dairies

Source: Jim Bruer, Applied Quantum Technologies

 

One study conducted by Dr. Craig Thomas of Michigan State University² evaluated dairy water use by “direct” and “indirect” functions.

• Direct Water Use was deemed to be drinking water for dairy animals.
• Indirect Water Use consisted primarily of cleaning cows, facilities and equipment in relation to milking operations. The study included a small allowance of water use for milk cooling that was recycled, and a small contingency for “miscellaneous” water uses.  

 

Water use was then estimated for a hypothetical 1,000 cow dairy farm, with and without heifers. This study produced an estimate of 25.5 to 67.5 gallons per day per dairy cow. This estimate does not include any water for cooling cows or for irrigation of fodder crops. It also does not include recycling water within the milking parlor.

Similar studies have been conducted by university research organizations throughout the U.S. and overseas with significant variations in the quantity of indirect water use.

A general benchmark that is often cited by industry experts is 100-200 gallons per day per dairy cow. Actual usage varies significantly with climate (temperate and humidity), facility design and operations, and also whether heifers are raised on the same dairy farm.

Using the 100 gallons per day estimate, Tulare County’s 471,081 dairy cows would require 17.2 billion gallons per year (52,785 AF). Virtually all of the water used by dairies is groundwater, and the water used for cow drinking and cleaning is mostly freshwater, although there now concerted efforts to recycle water wherever it is economically feasible.

Significantly, however, water used to clean cows, the milking parlor, flushing stalls, and other uses flow to manure lagoons where large solids are removed and dried for use as fertilizer, cattle bedding, and other purposes. The remaining wastewater is typically used to irrigate crops, especially fodder crops such as alfalfa. In this manner, dairies recycle as much effluent from the manure lagoon as possible.

The primary challenge is that biosolids and other particles that are not removed during the manure sludge dewatering process clog drip irrigation systems. Consequently, dairy farmers have needed to flood irrigate alfalfa and other fodder crops.

DWR estimated that during water year 2010, alfalfa crops consumed 5.2 million acre-feet of water (1,694 billion gallons), 37% more than the next highest water consumer: tree nuts (almonds and pistachios).

 

Figure 13. Applied Water per Crop (2010)

Source: Cooley, Heather. California Agricultural Water Use: Key Background Information. Pacific Institute. April 2015. Prepared from data provided by the Department of Water Resources.

 

Technology is currently poised to substantially change alfalfa’s standing as the highest agricultural water user in California.

Sustainable Conservation, a California-based 501c3 tax-exempt organization; Netafim USA, an irrigation technology solutions provider; and De Jager Farms, a dairy farm in Madera County, have been working for several years on a technology demonstration project that mixed fresh water with dairy manure wastewater to produce a liquid manure that could be delivered to a crop’s roots via drip tape for maximum absorption. The pilot system “… increased nitrogen use efficiency by more than 50%, reduced water use by 30%, and increased crop yields. In addition, the system significantly reduced nitrous oxide, a greenhouse gas generated when fertilizer and water mix that is over 200 times more potent than carbon dioxide, compared to traditional flood irrigation.”³  

In 2016, Sustainable Conservation announced that it had received a Conservation Innovation Grant from the U.S. Department of Agriculture in the amount of $833,000 to expand its technology demonstration to additional dairies in San Joaquin Valley. The primary benefit of liquid manure over traditional drip irrigation is the ability to utilize the manure as fertilizer, avoiding need to purchase and apply synthetic fertilizers.

De Jager Farms has reported that applying liquid manure via drip irrigation has reduced applied water for corn silage by 25% and increased crop yield 20-25%, a net water efficiency gain of 40%.

 

Figure 14. Dairy Wastewater Effluent

Source: Air Resources Board Dairy and Livestock Working Group

 

Tulare County dairy farmers are currently investigating multiple technology solutions that could enable use of dairy manure effluent with drip irrigation. One farmer stated that converting his planted alfalfa acreage to drip vs. flood would reduce the quantity of applied water from 3.5 AF/acre to 2.8 AF (water use reduction of 20%) while concurrently increasing the alfalfa yield from 9 tons to 12 tons per acre (an increase in yield of 33%). The net benefit of this strategy would reduce water use from 3.5 AF of water per 9 tons of alfalfa production (0.39 AF/ton) to 2.8 AF of water per 12 tons of alfalfa (0.23 AF/ton), a savings of 41%.

Tulare dairy farmers hope to find a technology solution that will remove enough of the remaining particles in dairy manure effluent to enable using it directly for drip irrigation without the need to add more water. The ideal solution will also remove some, but not all of the nutrients, in order to comply with new regulations reducing nutrient concentration limits⁴ while also retaining sufficient nutrients to avoid the need to add synthetic fertilizers.