A highly successful soil testing program has helped Rio Grande Valley farmers save almost $2 million in fertilizer expenses while protecting a body of water critical to the ecology of South Texas, according to Texas AgriLife Extension Service officials.

The AgriLife Extension educational program has helped growers significantly reduce the amount of crop fertilizer that might otherwise have ended up in the watershed of the Arroyo Colorado, said Brad Cowan, an AgriLife Extension agent in Hidalgo County.

"Since its inception in 2002, this program, Nutrient Management Education in the Rio Grande Valley, has helped farmers save an estimated 3.3 million pounds of nitrogen and 3.8 million pounds of phosphorus,” Cowan said.

At a time when increasing fertilizer prices have become a major concern for agricultural producers, the program has taken on a new importance.

“From 2002 to 2007, the cost of fertilizer more than doubled,” Cowan said. “It has more than doubled again just in the past year, so soil testing has become a critical step in reducing costs to growers and in reducing runoff to the environment.”

Through educational workshops and field days, more than 1,400 growers have received soil probes, testing forms and bags to collect soil samples. They are sent to Texas A&M University’s Soil, Water and Forage Testing Laboratory in College Station for analysis.

The soil testing is partially subsidized by the Rio Grande Basin Initiative, a project administered by Texas A&M AgriLife’s Texas Water Resources Institute.

The laboratory has tested and analyzed at least 3,000 soil samples representing more than 120,000 acres in Cameron, Hidalgo, Starr and Willacy counties, Cowan said.

The soil fertility results are returned to growers, along with nutrient management recommendations.

“Based on the test results, many growers have been able to reduce the amount of fertilizer they use which translates into huge cost savings,” said Dr. Enrique Perez, an AgriLife Extension agent in Cameron County.

“Depending on a grower’s crop and management history, they could save from $7.50 to $27.50 per acre on fertilizer costs by using the soil test results,” he said. “That puts the total economic impact from this project at an estimated $1.9 million, based on an average cost per pound of nitrogen and phosphorus.”

In addition to helping the bottom line of growers, the reduction in fertilizer use helps protect the Arroyo Colorado, which runs 90 miles from Mission to the Lower Laguna Madre and is on the state’s list of impaired waters.

The Arroyo’s watershed covers most of Hidalgo, Cameron and Willacy counties, home to about 1 million people, according to a 2006 census report.

Cecilia Wagner, who manages five water quality projects in the Arroyo Colorado for the Texas Water Resources Institute, said agricultural runoff containing excess nitrogen and phosphorus from fertilizers is one of several sources of pollution to the Arroyo Colorado.

Others are wastewater treatment plants and urban storm-water runoff.

“By reducing the amount of fertilizer applied to the fields, the nutrient management program basically translates into better water quality for the watershed,” she said. “It has helped the Arroyo Colorado Watershed Partnership move toward its goal of restoring the quality of waters in the area.”

The watershed partnership is a group of some 700 area citizens and representatives of federal and state agencies, local governments and private organizations working to restore the Arroyo Colorado.

The institute administers the partnership with funding provided by the Texas Commission on Environmental Quality and the U.S. Environmental Protection Agency.

But the key to the success of the program has been the soil testing program, said Cowan.

“It has shown outstanding results,” he said. “We consistently encourage growers to conduct annual soil testing because it’s a very important best management practice in agricultural production systems.”

In addition to Cowan and Perez, others who helped put together the multi-year educational and training program include Omar Montemayor, an AgriLife Extension agent from Starr County, and AgriLife Extension specialists Dr. Mark McFarland and Dr. Tony Provin.

In early 2007, the Arroyo Colorado Watershed Partnership completed and released “A Watershed Protection Plan for the Arroyo Colorado,” Wagner said. Among its recommendations, the plan encourages voluntary reductions by wastewater treatment facilities, improved wastewater infrastructure for “colonias” and other unincorporated areas and increased public education efforts.

More information on the partnership and projects in the Arroyo is available at www.arroyocolorado.org.

The Nutrient Management Education Program is supported by a Clean Water Act grant from the Texas State Soil and Water Conservation Board and the Environmental Protection Agency.

The program is part of the Rio Grande Basin Initiative funded by the U.S. Department of Agriculture-Cooperative State Research, Education and Extension Service.