University of Hawaii at Manoa

What you'll study

The PhD is structured around an intensive period of coursework followed by independent research leading to a dissertation. Core areas of study include soil genesis and classification, soil chemistry, soil physics, soil microbiology and biogeochemistry, and land‑use impacts on soil properties. Students typically take advanced seminars in statistics and experimental design, soil mapping and pedometrics, remote sensing and GIS for soil studies, and tropical soil management.

Field and laboratory methods are emphasised: courses and practicals cover soil sampling and characterisation, nutrient cycling assays, greenhouse gas flux measurements, soil hydrology and erosion assessment, and laboratory techniques in mineralogy and organic matter analysis. Students develop a research proposal, pass a qualifying or comprehensive examination, and form a supervisory committee to guide dissertation research. Interdisciplinary electives allow integration with related areas such as hydrology, volcanology, forestry, agronomy, ecology and climate science.

Entry requirements

Applicants are expected to hold a relevant graduate degree (typically an MSc) in soil science, geology, agronomy, environmental science, ecology or a closely related discipline; exceptional candidates with a strong bachelor’s degree and substantial research experience may also be considered. Typical application materials include academic transcripts, a statement of research interests, a curriculum vitae, and at least three letters of recommendation from academic or professional referees. A clear research proposal that aligns with faculty expertise strengthens an application.

Because the programme is taught and researched in English, international applicants must demonstrate English proficiency through recognised tests or equivalent qualifications where required. Prior experience with fieldwork, laboratory techniques and quantitative data analysis is highly desirable. Funding decisions and assistantship offers are competitive and often depend on availability of faculty supervision and research grants.

Career prospects

Graduates of the PhD in Soil Sciences pursue careers across academia, government, industry and the non‑profit sector. Common roles include university faculty and postdoctoral researchers, soil scientists and research scientists in national and state agencies (for example in agriculture, natural resources and environmental protection), consultants in environmental and agricultural firms, and technical experts for international development agencies addressing land management and food security.

Because of the programme’s emphasis on tropical and island soils, alumni are also well‑placed for specialist positions dealing with volcanic soils, coastal and watershed management, restoration ecology, and climate‑related issues such as carbon sequestration and greenhouse gas emissions from soils. Skills in field methods, quantitative analysis and interdisciplinary collaboration are readily transferable to roles in conservation organisations and private sector R&D.

Why study at University of Hawaii at Manoa

The University of Hawaii at Manoa provides a unique setting for soil‑science research through its focus on tropical and Pacific island environments. The programme is housed within colleges and departments that specialise in tropical agriculture and environmental resources, offering access to long‑term field sites across multiple Hawaiian islands and diverse ecosystems—from volcanic substrates to tropical forests and coastal plains.

Students benefit from established collaborations with state and federal agencies, extension services and international research partners, as well as well‑equipped laboratories for soil chemistry, mineralogy, physical measurements and stable isotope analyses. The local landscape and climate enable hands‑on study of processes that are less accessible elsewhere, such as rapid weathering of volcanic soils, tropical nutrient cycling and land‑use change impacts. The university’s emphasis on community engagement and applied research also creates opportunities for extension, outreach and policy‑relevant projects that connect science to local and regional needs.