** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE NITROGEN CYCLE IS ONE OF THE MOST IMPORTANT BIOGEOCHEMICAL SYSTEMS THAT SUPPORTS ALL LIFEFORMS AND UNDERPINS ALL FOOD PRODUCTION. NITROGEN FIXATION COMPRISES 2% OF ALL HUMAN ENERGY CONSUMPTION; MAN-MADE NITROGEN INPUT TO AGRICULTURAL AND INDUSTRIAL LAND NOW EXCEEDS NATURAL NITROGEN FIXATION. NITRATE IS THE MOST PROMINENT FORM OF NITROGEN NUTRIENT IN AGRICULTURAL LANDS, AT THE INTERSECTION BETWEEN PATHS OF THE NITROGEN CYCLE DRIVEN BY NATURE AND HUMANS. NITRATE CONTENT IN THE SOIL OF AGRICULTURAL LANDS DYNAMICALLY VARIES IN SPACE AND TIME. OUTSTANDING CHALLENGES PERSIST ON THE NEED FOR A REAL-TIME FIELD-DEPLOYABLE SENSOR WITH SUSTAINED CHEMICAL SPECIFICITY AND SENSITIVITY IN THE PRESENCE OF COMPLEX CHEMICAL AND ENVIRONMENTAL FACTORS.WE WILL USE LASER SPECTROSCOPY TO DETECT CHEMICALLY SPECIFIC MOLECULAR VIBRATIONS OF SOIL NITRATES. WE WILL UTILIZE METAL NANOSTRUCTURES TO ENHANCE THE SPECTRAL SIGNAL INTENSITY AND BOOST DETECTION SENSITIVITY. AFTER ESTABLISHING THE FUNDAMENTAL SCIENTIFIC ASPECTS OF NITRATE DETECTION VIA LASER RAMAN SPECTROSCOPY, WE WILL DESIGN AND TEST FOR FIELD DEPLOYMENT OF THIS SPECTROSCOPY SENSING PLATFORM. WE ENVISION THIS RESEARCH TO SIGNIFICANTLY INCREASE THE THROUGHPUT AND TEMPORAL/SPATIAL RESOLUTION OF SOIL NITROGEN MEASUREMENT WHILE YIELDING MULTIDIMENSIONAL CHEMICAL INFORMATION. THE TURN-AROUND TIME FROM SAMPLE TO DATA WILL BE REDUCED FROM DAYS TO MINUTES, A TWO-TO-THREE ORDER OF MAGNITUDE DECREASE, SIMILAR FOR COST PER DATA POINT. THIS WILL ENABLE US TO NOT ONLY QUANTIFY SOIL NITROGEN CONTENT, BUT ALSO CAPTURE THEIR SPECIATION AND DYNAMICS AT UNPRECEDENTED LEVELS.