Skip to main content
ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » People » Gilbert Sigua

Gilbert Sigua

Research Soil Scientist


Gilbert Sigua

Research Soil Scientist
Coastal Plains Soil, Water, and Plant Research Center
2611 West Lucas St., Florence, SC 29501-1242
843-669-5203 x105

Dr. Sigua is a nationally and internationally recognized authority in agronomic, soil, and environmental quality and management. Throughout his career, Dr. Sigua has consistently demonstrated outstanding originality and creativity for finding solutions to complex agricultural problems by conceiving and successfully conducting research projects in multifaceted scientific areas and diverse project management on protection, soil fertility management and sustainability of natural resources and water resources systems in the USA and other countries such as Brazil, Japan, Cambodia, Ethiopia, and the Philippines. Dr. Sigua’s scholarly achievements, expertise, and professional status have been widely recognized through numerous national and international honors and awards. As a testimony to this, he was recently awarded major awards, to wit: (a) Fellow of American Society of Agronomy; (b) William F. Fulbright Fellow; (c) Japan Society for Promotion of Science Fellow; (d) Department of Science and Technology “Balik Scientist” Fellow, Philippines; (e) Fellow of Soil Science Society of America; and (f) “Gintong Butil” (Golden Grain) Award for Science and Technology, CLSU Alumni. Dr. Sigua is currently serving as the U.S. government-supported mentor for the USAID-National Science of Academy funded Partnerships for Enhanced Engagement in Research (PEER) project in Cambodia.

Education and Training:

Ph.D., Louisiana State University, Agronomy Dept., major in Soil Sciences.

M.S., University of Arkansas, Fayetteville, AR, major in Soil Sciences.

B.S., Central Luzon State University, Philippines, major in Soil Sciences.

Professional Experience:

Research Soil Scientist, Coastal Plains Soil, Water and Plant Research Center, USDA-ARS, Florence, SC.

Research Soil Scientist, Subtropical Agricultural Research Station, USDA-ARS, Brooksville, FL.

Environmental Scientist, Division of Environmental Sciences, St. Johns River Water Management District, Palatka, FL.

Research Soil Scientist (Post-Doctoral), Environmental Chemistry Laboratory, USDA-ARS, Beltsville, MD.

Post-Doctoral Soil Scientist, Louisiana State University, Baton Rouge, LA

Research Assistant, Louisiana State University, Agronomy Department, Baton Rouge, LA.

Professor, Department of Soil Sciences, Central Luzon State University, Philippines.

Instructor, Department of Soil Sciences, Central Luzon State University, Philippines.

Selected Publications:

• Sigua, G.C., Novak.J., Watts, D., Myers, W.T., Ducey, T., and Stone, K.C. 2020. Urease activity and nitrogen dynamics in highly weathered soils with designer biochars under corn cultivation. Biochars. 2020.

• Olszyk, D.M., Shiroyama, T., Novak, J.M., Cantrell, K.B., Sigua, G.C., and Watts, D.W. 2020. Biochar affects essential nutrients of carrot taproots and lettuce leaves. HortScience. 55(2):261–271.

• Sohoulande, C., Szogi, A.A.Sigua, G.C., Stone, K.C. 2020. Evaluating nitrogen management for corn production with supplemental irrigation on sandy soils of the southeastern coastal plain region of the united states. Transactions of the ASABE 63(3):731-740.

• Ippolito, J. A., Liqiang, C., Kammann, C., Wrage-Mönnig, N., Estavillo, J.M., Fuertes-Mendizabal, T., Cayuela, M.L., Sigua, G.C., Novak, K., Spokas, S., and Borchard, N. 2020. Feedstock Choice, Pyrolysis Temperature and Type Influence Biochar Characteristics: A Comprehensive Meta-Data Analysis Review. Biochars /s42773-020-00067-x.

• Sigua, G.C., Novak, J.M., Watts, D.W., Ippolito, J.A., Ducey, T.F., Johnson, M.G., and Spokas, K.A. 2019. Phytostabilization of Zn and Cd in mine soil using corn in combination with biochars and mnaure-based compost. Environments. 6, 69. doi: 10.3390/ environments6060069.

• Shugang, Z., Yang, Y., Zhai, W., Tong, Z., Shen, T., Li, Y.C., Zhang, M., Sigua, G.C., Chen, J., and Ding, F. 2019. Controlled-release nitrogen fertilizer improved lodging resistance and potassium and silicon uptake of direct-seeded rice. Crop Science 59:2733–2740. doi:10.2135/cropsci2018.12.0765.

• Sigua, G.C., Stone, K.C., Bauer, P.J., and Szogi, A.A. 2018. Biomass and nitrogen-use efficiency of grain sorghum (Sorghum bicolor L.) with nitrogen and supplemental irrigation in Coastal Plain Region, USA. Agron. J. 110(2): 1119-1127. doi: 10.2134/ agronj2017.09.0533.

• Sigua, G. C., Stone, K.C., Bauer, P.J., Szogi, A.A., and Shumaker, P.D. 2017. Impact of irrigation scheduling on pore water nitrate and phosphate in Coastal Plain Region, USA with maize production. Agricultural Water Management. 186: 75-85.

• Sigua, G. C., Stone, K.C., Bauer, P.J., and Szogi, A.A. 2017. Phosphorus dynamics of soils under maize production with supplemental irrigation in humid Coastal Plains region, USA. Nutr Cycl Agroecosyst. 109: 249-267.

• Edralin, D.I., Sigua, G.C., Reyes, M.R., Mulvaney, M., and Andrew, S.2017. Conservation agriculture improves yield and reduces weeding acivity in sandy soils of Cambodia. Agron. Sustain. Dev. 37:52-62. DOI: 10.1007/s13593-017-0461-7.

• Sigua, G. C., Hunt, P.G., Stone, K.C., Cantrell, K.B., and Novak, J.M. 2016. Increasing biomass of winter wheat using sorghum biochars. Agron. Sustain. Dev. 35:739-748.

• Edralin, D.I., Sigua, G. C., Reyes, M.R. 2016. Dynamics of soil carbon, nitrogen and soil respiration in farmer’s field with conservation agriculture, Siem Reap, Cambodia. International Journal of Plant & Soil Science. Vol 11(1): 1-13.

• Sigua, G.C., Novak, J. M., and Watts. D. 2015. Ameliorating soil chemical properties of a hard setting subsoil layer in coastal plain USA with different designer biochars. Chemosphere. 142:168-175.

• Sigua, G.C., Hunt, P.G., Stone, K.C., Cantrell, K.B., and Novak, J.M. 2015. Increasing biomass of winter wheat using sorghum biochars. Agronon Sustainable Develoment. 35:739-748.

• Sigua, G.C. 2015. Phosphorus dynamics and management in forage-based agroecosystem with cow-calf operation. Sustain. Agric. Rev.17:29-60. • Sigua, G.C. Novak, J. Watts, D.. and Johnson, M. 2015. Efficacies of designer Biochars in improving biomass and nutrient uptake of winter wheat grown in a hard setting subsoil layer. Chemosphere. Chemosphere. 142:176-183.

• Novak, J.M., Sigua, G.C., Watts, D. Cantrell, K. Shumaker, P., Szogi, A. Johnson, M. and Spokas, K. 2015. Biochars impact on water infiltration and water quality through a compacted subsoil layer. Chemosphere. 142:160-167.

• Novak, J.M., Ro, K.S., Ok, Y.Y., Sigua, G.C., Spokas, K.A., Uchimiya, S.M., and Bolan, N. 2015. Biochars multifunctional role as a novel technology in the agricultural, enviornmental, and industrial sectors. Chemosphere. 142:1.

• Sigua, G.C., and Chase, C.C. 2014. Groundwater phosphorus in forage-based landscape with cow-calf operations. Environ. Monit. Assess. 186:1317-1326.

• Sigua, G.C., Novak, J., Watts, D., Cantrell, K., Shumaker, P., Szogi, A., and Johnson, M. 2014. Carbon mineralization in two Ultisols amended with different sources and particle sizes of biochar. Chemosphere. 103:313-321.

• Sigua, G.C., Hunt, P.G., Stone, K.C., Cantrell, K.B., and Novak, J.M. 2014. Contrasting effects of sorghum biochars and sorghum residues on soil chemical changes of Cosatal Plains Ultisols with winter wheat. Soil Sci. 179:369-408.

• Novak, J.M., Sigua, G.C., Busscher, W.J., Cantrell, K., Watts, D.W., Glaz, B., and Hunt, P. 2014. Plant macro and micro-nutrient dynamics in a biochar-amended wetland muck. Water Air Soil Poll. 226:1-9.

• Sigua, G.C., Coleman, S.W., Albano, J., and Williams, M. 2011. Spatial distribution of soil phosphorus and herbage mass in beef cattle pastures: effects of slope aspect and slope position. Nutr. Cycl. Agroecosys. 89: 59-70.