Use of tensiometer for in situ measurement of nitrate leaching
In order to monitor nitrate leaching from non-point source pollution, this study used tensiometers to measure in situ nitrate concentration and soil-moisture potential. Instead of filling the tensiometers with pure water, the study filled the tensiometers with nitrate ionic strength adjuster (ISA, 1 M (NH{sub 4}){sub 2}SO{sub 4}). After the installation of the tensiometers at various depths along soil profiles, a portable pressure transducer was used to measure the soil moisture potential, and a nitrate electrode attached to an ion analyzer was used to measure the nitrate concentration in situ. The measurement was continuous and non-destructive. To test this method in the laboratory, eight bottles filled with pure sand were treated with known nitrate solutions, and a tensiometer was placed in each bottle. Measurements were taken every day for 30 days. Laboratory test showed a linear relationship between the known nitrate concentration and the tensiometer readings (R{sup 2} = 0.9990). Then a field test was conducted in a watermelon field with green manure mulch. Field data indicated a potential of nitrate leaching below the soil depth of 100 cm when crop uptake of nutrients was low.
- Research Organization:
- North Carolina A and T State Univ., Greensboro, NC (US)
- OSTI ID:
- 20005867
- Resource Relation:
- Conference: Field Instrumentation for Soil and Rock, Atlanta, GA (US), 06/18/1998--06/19/1998; Other Information: PBD: 1999; Related Information: In: Field instrumentation for soil and rock. ASTM special technical publication 1358, by Durham, G.N.; Marr, W.A. [eds.], 426 pages.
- Country of Publication:
- United States
- Language:
- English
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