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United States Department of Agriculture

Agricultural Research Service

Title: Evaluation and Mitigation of Pollutant Transport in Agricultural Sandy Soils

Authors
item Alva, Ashok
item Alva, Ashok
item Collins, Harold
item Collins, Harold
item Paramasivam, S - SAVANNAH STATE UNIV, FL
item Paramasivam, S - SAVANNAH STATE UNIV, FL
item Sajwan, K - SAVANNAH STATE UNIV, FL
item Sajwan, K - SAVANNAH STATE UNIV, FL
item Fares, A - UNIV OF FL, LAKE ALFRED
item Fares, A - UNIV OF FL, LAKE ALFRED

Submitted to: World Congress of Soil Science
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2001
Publication Date: August 1, 2002
Citation: ALVA, A.K., COLLINS, H.P., PARAMASIVAM, S., SAJWAN, K., FARES, A. EVALUATION AND MITIGATION OF POLLUTANT TRANSPORT IN AGRICULTURAL SANDY SOILS. TRANSACTIONS OF THE SEVENTEENTH WORLD CONGRESS OF SOIL SCIENCE, (ON CD) PAPER #458, 0458.PDF. 2002.

Interpretive Summary: Agricultural production in some parts of the Pacific Northwest (PNW) and southeastern agricultural regions in the United States are being done in sandy soils which contain 95 to 98% sand in the soil profile to a depth of up to 9-10 feet with no soil horizons to restrict the downward flow of water and pollutants. The Columbia Basin region in the PNW represents the premier potato production region of the U.S. with maximum production of over 35 tons/acre of high quality processed potatoes. However, in some production areas NO3-N concentrations in the shallow groundwater have increased in excess of 10 mg per liter, which is the maximum contaminant level (MCL) for drinking water quality standards. Bromide (Br) is used as an indicator of water and pollutant transport in the soil. A study conducted in a sandy soil with application of 100 lbs/acre Br, showed that the peak Br- concentration in the soil surface disappeared within 21 d after application, and Br- was leached entirely from the top 8 feet depth soil profile by 42 d after application. In another study with sandy soils used for 25+ year old citrus trees which received 25 to 100 lbs N/acre under carefully scheduled irrigation, NO3- concentrations in the surface 8 feet depth soil profile returned to background concentrations (<1 mg kg-1 as NO3-N) by 35 to 42 d after application of N. The lateral flow rate of groundwater can be about 3 inches per day. Therefore, nitrate contamination to groundwater in one area can eventually contaminate a large body of water over a long period of time.

Technical Abstract: Sandy soils in some parts of the Pacific Northwest (PNW) and southeastern agricultural regions in the United States contain 95 to 98% sand in the soil profile to a depth of up to 2.5 m with no confining soil horizons. In some areas, these soils may have shallow groundwater, thus providing favorable conditions for leaching of surface applied chemicals and soluble nutrients that could contaminate the groundwater. In some parts of eastern Washington state, there has been an increase in groundwater NO3-N concentration in the shallow aquifer in excess of 10 mg per liter, which is the maximum contaminant level (MCL) for drinking water quality standards. The Columbia Basin region in the PNW represents the premier potato production region of the U.S. with maximum production (78 Mg/ha) of high quality processed potatoes. A Bromide tracer study, conducted in a sandy Entisol showed that the peak Br- concentration in the soil surface disappeared within 21 d after application, and Br- was leached entirely from the top 2.4 m depth soil profile by 42 d after application. In a study with 25+ year old citrus trees, with application of either 28 to 112 kg N ha-1, NO3- concentrations in the surface 2.4 m depth soil profile returned to background concentrations (<1 mg kg-1 as NO3-N) by 35 to 42 d after application of N, across all N rate treatments. The lateral flow rate in the aquifer can be about 0.08 m d -1. Therefore, the source of the non-point pollution of NO3- in one area can in turn affect a large body of groundwater.

Submitted to: World Congress of Soil Science
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2001
Publication Date: August 1, 2002
Citation: ALVA, A.K., COLLINS, H.P., PARAMASIVAM, S., SAJWAN, K., FARES, A. EVALUATION AND MITIGATION OF POLLUTANT TRANSPORT IN AGRICULTURAL SANDY SOILS. TRANSACTIONS OF THE SEVENTEENTH WORLD CONGRESS OF SOIL SCIENCE, (ON CD) PAPER #458, 0458.PDF. 2002.

Interpretive Summary: Agricultural production in some parts of the Pacific Northwest (PNW) and southeastern agricultural regions in the United States are being done in sandy soils which contain 95 to 98% sand in the soil profile to a depth of up to 9-10 feet with no soil horizons to restrict the downward flow of water and pollutants. The Columbia Basin region in the PNW represents the premier potato production region of the U.S. with maximum production of over 35 tons/acre of high quality processed potatoes. However, in some production areas NO3-N concentrations in the shallow groundwater have increased in excess of 10 mg per liter, which is the maximum contaminant level (MCL) for drinking water quality standards. Bromide (Br) is used as an indicator of water and pollutant transport in the soil. A study conducted in a sandy soil with application of 100 lbs/acre Br, showed that the peak Br- concentration in the soil surface disappeared within 21 d after application, and Br- was leached entirely from the top 8 feet depth soil profile by 42 d after application. In another study with sandy soils used for 25+ year old citrus trees which received 25 to 100 lbs N/acre under carefully scheduled irrigation, NO3- concentrations in the surface 8 feet depth soil profile returned to background concentrations (<1 mg kg-1 as NO3-N) by 35 to 42 d after application of N. The lateral flow rate of groundwater can be about 3 inches per day. Therefore, nitrate contamination to groundwater in one area can eventually contaminate a large body of water over a long period of time.

Technical Abstract: Sandy soils in some parts of the Pacific Northwest (PNW) and southeastern agricultural regions in the United States contain 95 to 98% sand in the soil profile to a depth of up to 2.5 m with no confining soil horizons. In some areas, these soils may have shallow groundwater, thus providing favorable conditions for leaching of surface applied chemicals and soluble nutrients that could contaminate the groundwater. In some parts of eastern Washington state, there has been an increase in groundwater NO3-N concentration in the shallow aquifer in excess of 10 mg per liter, which is the maximum contaminant level (MCL) for drinking water quality standards. The Columbia Basin region in the PNW represents the premier potato production region of the U.S. with maximum production (78 Mg/ha) of high quality processed potatoes. A Bromide tracer study, conducted in a sandy Entisol showed that the peak Br- concentration in the soil surface disappeared within 21 d after application, and Br- was leached entirely from the top 2.4 m depth soil profile by 42 d after application. In a study with 25+ year old citrus trees, with application of either 28 to 112 kg N ha-1, NO3- concentrations in the surface 2.4 m depth soil profile returned to background concentrations (<1 mg kg-1 as NO3-N) by 35 to 42 d after application of N, across all N rate treatments. The lateral flow rate in the aquifer can be about 0.08 m d -1. Therefore, the source of the non-point pollution of NO3- in one area can in turn affect a large body of groundwater.

Last Modified: 7/30/2014
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