2010 Annual Report 1a.Objectives (from AD-416) ARS is interested in determining chemical properties in tropical soils and in the assessment of elemental composition of tropical plants. 1b.Approach (from AD-416) Plant (cacao, cover crops) and soil samples of tropical crops will be collected from field studies carried out in Peru and Brazil and will be transported to the U.S. under APHIS soil and plant import permits. Soil chemical (pH, C, N, macro and micro nutrients: N, P, K, Ca, Mg, Na, Zn, Cu, Fe, B, Mn, etc.) and biological properties (microbial biomass- of C, -N, -P) and plant mineral compositions (C, N, Ca, Mg, K, P, Na, S, Al, Zn, Cu, B, Fe, Mn, etc.) will be determined at the University of Florida, Indian River Research and Education Center (IRREC), Fort Pierce, Florida. Soil and plant (cacao, cover crops) samples will be collected from experiments conducted at SPCL facilities at Beltsville, MD. These soil and plant will be analyzed for macro and micronutrients (N, C, Ca, Mg, K, P, Na, Al, Zn, Cu, B, Fe, Mn, etc.) at the University of Florida, IRREC, Fort Pierce, FL. 3.Progress Report This agreement provides funds for the elemental analysis of soil and plant samples from cacao and cover crops grown in Beltsville, Maryland, Bahia, Brazil, and Tarapoto, Peru. During this reporting period 140 plant tissue samples and 7 water samples were analyzed for macro- and micro-elements. The water samples were analyzed for the concentrations of anions including fluoride, chloride, sulfate, bromide, nitrate, and phosphate using Ion Chromatography following USEPA method 300.0, and for the concentrations of Al, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, and Zn using the ICP-OES following USEPA method 200.7. The plant samples were analyzed for the total concentrations of N, P, K, Ca, Mg, Al, B, Cd, Co, Cr, Cu, Fe, Mn, Mo, Na, Ni, Pb, and Zn. The progress of this agreement was monitored by e-mails, phone or by personal communications between the principal investigators for this project.