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Title: REAL-TIME NITRATE EXTRACTION FROM SOIL CORES

Author
item PRICE, RANDY - UNIV OF ILLINOIS
item Hummel, John
item AHMAD, IRFAN - UNIV OF ILLINOIS
item BIRRELL, STUART - UNIV OF ILLINOIS

Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Commercialization of a real-time nitrate sensing system would allow site-specific control of fertilizer application rates. Better control of fertilizer application could have a positive effect on crop production profitability while also reducing the amount of nitrate that leaches from farm fields and contaminates drinking water sources. In this research, an intact core extraction procedure was tested that might be used in the field for real-time prediction of soil nitrates. An extracting solution was pushed through a soil core held between two filters, and an ion selective field effect transistor/flow injection analysis (ISFET/FIA) system was used to sense soil nitrates in real time. Laboratory tests were conducted using four soil types, and two levels of nitrate concentration, soil moisture, core length, core diameter, and extraction solution flowrate. The extraction solution flow was sampled at the exit face of the core and routed to the ISFET/FIA system. The ISFET output voltage was sampled at 100 Hz. Results of the test indicate that nitrate extraction and washout occurred in the soil cores, and that peak slope, and cumulative area data descriptors of the nitrate extraction curve indicate prediction in a few seconds. The presentation will include discussion of the significance of the variables tested with regard to the development of a real-time nitrate sensor for field use.