Soil sampling: representation and chain-of-custody plan

Overview

# Soil sampling: representation and chain-of-custody plan

## Goal and required inputs

Deliver identifiable samples with a documented route from the planned zone to laboratory acceptance. Obtain written, purpose-specific laboratory instructions for depth, subsample count, zone separation, cleaning, containers, storage and delivery. Assign a sampler and recipient, and confirm safe access. Do not start collection while required instructions are missing. Seven days is a planning horizon, not a laboratory-result promise.

## Procedure

1. Choose Adapt to my program to create a private farm program without a public Hub profile, edit days/inputs and preview fields/start date before creating tasks. Review six tasks: laboratory instructions day 0, zones day 1, supplies day 2, collection day 3, handoff day 4, acceptance/review planning day 7.
2. Describe actual field zones and management/history differences privately. Ask the lab which zones must stay separate; do not blend visibly different areas by default.
3. Issue a unique sample ID before collection and put it on both the container label and custody form.
4. Record the actual time, depth/unit, subsample count and deviations while collecting under the approved instruction.
5. Check container/storage requirements, log every handoff and reconcile the laboratory acceptance identifier. If results are pending, record that status and schedule review later.

## Deliverables and acceptance criteria

Create `sample-plan.csv`: `sample_id,field_id,zone_id,analysis_purpose,lab_instruction_reference,planned_depth,depth_unit,planned_subsample_count,container,storage,delivery_requirement`. Create private `chain-of-custody.csv`: `sample_id,event_time_with_timezone,event,from_alias,to_alias,actual_depth,depth_unit,actual_subsample_count,deviation,lab_acceptance_id,status`.
Accept the handoff only if each container has one unique ID, plan/label/form IDs agree, required method fields are complete and every transfer has time and responsible parties. Correct a damaged label before dispatch; never invent a depth or receipt. At result review, match sample ID and units to the original plan.

## Worked example and next action

Use fictional `DEMO-20260103-01` only to test that the same identifier passes through a draft plan, blank label and handoff form. Leave depth/count empty until the selected laboratory supplies them. [Sandbox boundaries](/hub/agridigi/sandbox-field-boundaries) can test a field-ID join but cannot provide sampling locations or hectares. After genuine lab acceptance, assign result review to an authorized expert; a fertilizer rate cannot be inferred from this template alone.

## Privacy, provenance and license

Do not publish precise farm coordinates, staff names or laboratory results without permission. Keep public demonstrations synthetic and actual custody records private. AgriDigi authored these tasks; the [USDA NRCS National Agronomy Manual](https://www.nrcs.usda.gov/sites/default/files/2022-10/National-Agronomy-Manual.pdf) is a linked background reference, not redistributed content or a replacement for current lab instructions. Original text/tasks are [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/): credit AgriDigi, link source/license and identify changes. No universal sampling depth, treatment, dose or turnaround is specified.

Action plan

Crop: Crop independent · Duration: 7 days

1. Obtain the laboratory's written purpose-specific instructions

   Day 0

   Ask the chosen lab for analysis purpose, depth/unit, subsample count, zone separation, cleaning, containers, storage and delivery rules. Deliver a referenced instruction and completed required fields in sample-plan.csv. Accept only written, applicable instructions; do not fill missing requirements with universal defaults or begin collection without them.

2. Define representative zones and keep different areas separate

   Day 1

   Record real field/zone IDs and management, history or soil differences privately. Confirm zone separation and representation with the lab; do not mix unlike areas by default. Deliver a zone note linked to the plan. Accept when each planned sample has a justified zone; sandbox GeoJSON is not a real sampling-point map.

3. Prepare matching labels, equipment and custody forms

   Day 2

   Prepare clean tools and containers required by the lab. Assign each planned sample a unique ID and copy it to the label and chain-of-custody.csv. Deliver a checked kit and ID cross-check. Accept when container, plan and form agree exactly, with no duplicate sample IDs; do not substitute unapproved storage materials.

4. Collect under the approved method and record actual conditions

   Day 3

   Follow safe access and the lab's written method. Record sample/field/zone ID, actual time and zone, actual depth/unit, subsample count, collector alias and deviations. Deliver collected samples plus complete collection events. Accept composite samples only from the defined compatible zone when instructed; keep unmeasured values unknown.

5. Reconcile containers and record every transfer

   Day 4

   Check required storage and dispatch conditions. Match label/form IDs, count containers and record sender/recipient aliases, actual transfer time and lab acceptance ID/status. Deliver a reconciled custody log. Accept only traceable transfers; correct damaged or missing labels before dispatch and do not invent acceptance information.

6. Confirm acceptance and schedule qualified result review

   Day 7

   Record whether the lab accepted the samples, requested correction or still has results pending. When results arrive, match IDs and units to the plan and assign an authorized expert review. Deliver a status summary and next task. Seven days is not a result guarantee; this template alone supplies no diagnosis or application dose.