GROUNDWORK / SCIENCE & RESEARCH

Groundwork.

One question keeps
becoming the next.

From microbes in Assam’s groundwater to soil health in Nebraska and long-term farming systems. A life of looking beneath the surface, and connecting what I find.

Explore the research Follow the journey

THE QUESTIONS HAVE ROOTS. Conceptual illustration

01 / CONNECT THE QUESTIONS

Research grows in connections.

Select a dot. See what the study contributed, what it could not settle, and where the question goes next.

Question to questionShared foundations

A reading path through related ideas, not a citation network. Lines show conceptual connections; years show publication dates.

QUESTION 01 / 05 2020

Better soil — compared with what?

The Soil Health Gap frames soil condition as a distance from an undisturbed reference within an agroecosystem. It gives improvement a benchmark, rather than treating an isolated test result as a verdict.

THE NEXT QUESTION

But soil and climate change the potential. Which sites can we fairly compare?

The reference and indicator matter; a gap is not a universal soil-health score.

Published paper

Soil Health Gap: A concept to establish a benchmark for soil health management

Maharjan, Das & Acharya · Global Ecology and Conservation · 2020

Read the paper

CONNECTED TOEcological units Hierarchical targets

QUESTION 02 / 05 2022

Which soils belong in the same comparison?

The Cropland Reference Ecological Unit (CREU) groups land with comparable soil-forming and climatic conditions. It helps separate differences caused by management from differences a field inherits from its environment.

THE NEXT QUESTION

A comparable area is only the start. Where, within it, should the reference come from?

CREU supplies ecological context; it does not make every soil or management history identical.

Published paper

Cropland Reference Ecological Unit: A land classification unit for comparative soil studies

Das & Maharjan · Ecological Indicators · 2022

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CONNECTED TOSoil Health Gap Reference sites Two-Tier framework Hierarchical targets

QUESTION 03 / 05 2024

What makes a reference defensible?

Reference-site selection uses ecological site descriptions and state-and-transition models to identify the appropriate reference plant community. The benchmark becomes an ecological condition to establish, rather than the nearest patch that looks undisturbed.

THE NEXT QUESTION

With a defensible reference in place, which measurements are useful enough to repeat?

Reference selection still requires field evidence and knowledge of disturbance history.

Published paper

Reference site selection based on state-and-transition models for soil health gap evaluation within cropland reference ecological units

Das, Hird, Maharjan, Stephenson & Kariyawasam · Soil Security · 2024

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CONNECTED TOEcological units Two-Tier framework

QUESTION 04 / 05 2026

Can measurement be consistent and interpretation local?

Tier 1 identifies a practical core: organic matter, pH, nitrate-N, and bulk density. Tier 2 interprets those measurements against ecologically matched reference distributions. The framework separates what to measure from what a result means in a particular soil and climate.

THE NEXT QUESTION

An ecological reference describes potential. What is a realistic next step for working cropland?

The reference dataset comes from Nebraska; broader transfer needs regional testing and calibration.

Published paper

A two-tier, reference-informed framework for soil health assessment: Minimum indicator sets and ecologically dynamic thresholds

Das, Gamage, Stephenson, Acharya, Daigh & Maharjan · Agrosystems, Geosciences & Environment · 2026

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CONNECTED TOEcological units Reference sites Hierarchical targets

QUESTION 05 / 05 2026

How do we turn potential into attainable progress?

Hierarchical Land Classification connects ecological reference, recovery, soil-building, production, and degraded states. A synthesis of 1,059 soil organic carbon observations from 105 studies examines intermediate targets between today's condition and ecological potential.

THE NEXT QUESTION

The open question: do these context-aware targets predict useful outcomes across more farms and regions?

Preprint. Recovery and soil-building states were not statistically distinguishable; targets are neither universal nor equally spaced.

Preprint · not peer reviewed

Hierarchical Land Classification for Soil Health Assessment: Linking Reference Potential, Management State, and Incremental Soil Health Targets

Das, Bora, Panday, Maharjan, Smith, Mamo, Hird, Singh & Garrity · SSRN · 2026

Read the preprint

CONNECTED TOSoil Health Gap Ecological units Two-Tier framework

STILL OPEN

Can a fairer benchmark lead to a better decision in the field?

Where research meets building

02 / THE LIFE BEHIND THE QUESTIONS

Different places. A continuing curiosity.

Water, then soil, then systems. Explore the chapters that changed what I ask and how I work.

Assam Agricultural University

Learning to see the invisible

What is happening in the water we cannot see?

Doctoral work in agricultural biotechnology took me into arsenic biogeochemistry, groundwater, and microbial communities in Assam. It built a habit that still shapes my research: look beneath the visible symptom and ask which living processes are driving it.

WHAT I CARRIED FORWARD

Follow the microbes. Pay attention to context. Start with a real problem in the field.

GroundwaterMicrobial ecologyArsenic

Explore the groundwater study

University of Nebraska–Lincoln

Learning to ask “compared with what?”

What does healthy soil mean in this particular field?

Postdoctoral and research faculty work moved those questions into agricultural soils: benchmarking, carbon and nitrogen, and the effects of management. Different soils kept resisting the same scorecard. That tension runs through the Soil Health Gap, ecological units, and reference-site work.

WHAT I CARRIED FORWARD

A measurement needs a fair comparison. A field has both a history and a potential.

Soil healthCarbon & nitrogenReference sites

Follow the benchmarking thread

Long-term farming systems research

Making the knowledge useful

How does evidence become something a farmer can use?

The journey now connects long-term farming systems research with practical indicators, attainable targets, and tools that make evidence easier to use. The same curiosity extends into building: how can careful science travel beyond a paper and become part of an everyday decision?

WHAT I CARRIED FORWARD

Connect ecological potential, present condition, and the next useful action.

Farming systemsAttainable targetsResearch into tools

See what I’m building

03 / OTHER THREADS IN THE WORK

Mechanisms, microbes & the bigger picture.

2026 · Position Paper

Soil Health in Practice: Principles, Proof, and the Path Forward

A systems-oriented look at how soil health moved from niche concept to organizing framework, and what kinds of evidence are still needed to connect management practices to measurable outcomes.

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2025 · Sustainability

Soil Carbon Sequestration: A Mechanistic Perspective on Limitations and Future Possibilities

Examines where soil carbon narratives are scientifically strong, where they become overstated, and what mechanistic understanding is required for credible long-term sequestration claims.

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2024 · Agrosystems, Geosciences & Environment

Soil Health Cycle

A framework for thinking about soil health as an iterative management cycle linking practices, indicators, functions, and human decision-making rather than as a one-time score.

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2024 · PLOS One

Nitrogen Dynamics as a Function of Soil Types, Compaction, and Moisture

Investigates how compaction and moisture regimes shape nitrogen transformations, leaching, volatilization, and emissions across contrasting soil textures.

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2018 · BMC Microbiology

Characterization of Siderophore Producing Arsenic-Resistant Staphylococcus sp. Strain TA6

A study of arsenic-resistant bacteria from contaminated groundwater in Assam and their possible role in the local arsenic geocycle.

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2017 · Genomics Data

A Metagenomic Approach to Decipher the Indigenous Microbial Communities of Arsenic Contaminated Groundwater of Assam

An early metagenomic investigation into the microbial communities inhabiting arsenic-affected groundwater systems, reflecting the foundation of my research journey.

Read the paper

THE JOURNEY IS A COLLABORATIVE ONE

Another dot to connect?

A research question, a shared field site, or an idea worth testing. I’d like to hear it.

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