Dr. Oriana, I think you may use ISEmaxCAS40D sensor. It is a digital ammonium and nitrate sensor produced by Endress + Hauser AG, in Switzerland. For more details you may go to www. endress.com.

You can also try compatible spark senser.

Best of Luck!

Dr. Tarafdar, thanks for the suggestion and for your efficient response!

 With recent advances in sensor technology, various techniques to quantify variability in soil nutrients have been developed and tested by many researchers. This paper describes sensor developments and related technologies that are applicable to the measurement of soil macronutrients in real-time for SSCM. First, various analytical techniques commonly used in soil N, P, and K analysis and the sensing principles of related laboratory instruments are discussed, along with considerations for the use of various soil extractants. Second, various types of soil macronutrient sensors, mainly based on optical and electrochemical methods, are reviewed.PDF enclosed

In Europe, legislation applying to “Nitrate Vulnerable Zones” requires farmers to

deal with nitrate loss from their land. Existing methods for measuring nitrate

levels in soil rely on taking samples of soil (or sometimes soil water) to a laboratory and waiting days or weeks for the data. Moreover, such sampling is

fraught with complications as nitrate levels vary with place and time,depending on environmental conditions especially water, soil type and temperature .

Nitrate transporter CHL1 also functions a nitrate sensor (transceptor). Phosphorylation statuses of CHL1 T101 residue are regulated by external nitrate concentration in the soil. ▶ Phosphorylation statuses of T101 can switch the affinities of CHL1 transport activity, and induce different levels of nitrate regulated transcriptional response...PDF enclosed

Please have a look at these PDFs

Dear Oriana

Hi, I'm not sure that the ISEmaxCAS40D sensor as indicated upper is adapted to the nitrate/ammonia soil analysis; I think this sensor is for liquid media.

what I know is there is just the technology developped by theJohn Innes Centre (Norwich, UK) and PBL society

This a Low cost in-situ electrode for detecting nitrate and other soil nutrients.  Also for rapid on-site assays, environmental monitoring and measuring plant nitrate levels.

you have to contact by mail [email protected] for this topic.

hoping this will help you

sincerely yours

Thierry

I agree with Thiery: you cannot embed conventional ISEs..  There are retrievable ion exchange membranes but then you are dealing with selectivity and diffusion rates  so you need large numbers.  But you need large numbers because of spatial variation.

Hi, there is an other system that's work very well, for nitrate and ammonium, 15N labeeled or not, this is the PRS (plant root simulator cationic and anionic membranes) . the company is western Ag in Canada. You can contact the head manager kenneth greer and indicates to him that the recommandation is from me.

for the technology developped by theJohn Innes Centre (Norwich, UK) and PBL society, you have to contact [email protected], because the sensors are not already on the market. to see with tony miller how you  can collaborate. Thierry