A quick‐test procedure for soil and plant tissue nitrates using test strips and a hand‐held reflectometer

Abstract

Development of a nitrate quick‐test for use by fanners or field consultants would likely encourage the use of plant tissue and soil nitrate tests as a means to improve nitrogen management. To evaluate a quick‐test method, nitrate concentrations in plant tissue and soils were measured using commercially available nitrate test strips and a hand‐held reflectometer. The results were compared with those obtained with standard laboratory methods. Test strip accuracy and precision and reflectometer precision were determined over a 10 day period using standard KNO₃solutions and colored paper strips. Coefficients of variation ranged from 22.4 to 9.5 percent for the test strips and from 3.5 to 1.6 percent for the reflectometer. Quick‐test results were highly correlated with laboratory results for both plant tissue nitrate (r=0.87) and soil nitrate (r=0.98) concentrations. Results indicated that test strips provide a rapid, reasonably accurate and precise method to determine nitrate concentrations in both soil and plant material

Key words:

• Quick‐test
• nitrate test strips
• reflectometer soil nitrate
• stalk nitrate

Notes

Paper No. 7858 of the Journal Series of the Penna. Agr. Exp. Station, University Park. Authorized for publication February 18, 1988.