OC-13.1: Change in soil macro-nutrient content

Owned by Enrico Bonaiuti
May 05, 2020
2 min read

Definition: This indicator will focus on soil nutrients that are in most demand by crops and supplied by fertilizers: nitrogen (N), phosphorus (P), and potassium (K).

Unit of Measure: Percentage

Disaggregated by: Agro-ecological zone, geographical area (national, sub-national)

Method of Calculation:
Step 1: Follow the instructions in this manual to measure soil macronutrient content
Step 2: Compute the change in soil macronutrient content as per the equation below
Change in soil Macronutrienti=Macroitn-MacroitoMacroito×100
Macroito denotes content of soil macronutrient i in the first reporting period (e.g baseline) and Macroitn denotes content of soil macronutrient i in subsequent reporting periods (e.g mid-term, end-term).

Data sources: Farmers' fields/plots

Data collection method: Soil sampling.
Additional remark on soil sampling: A soil sample should be composed of several sub-samples representing a seemingly uniform area or field with similar cropping and management history. It is recommended that eight sub-samples are taken per hectare (ha) in a diagonal pattern for obtaining one composite sample. Soil sampling Should be done at depths of about 20-cm and 60-100 cm. See detailed information in the Manual.

Data collection and reporting responsibility: Program leader, project leader, project M&E focal point person

Data Collection and Reporting Frequency: Annual, bi-annual, baseline, mid-term, end-term.
Additional remarks on soil sampling:

  • Soil samples can be taken any time that soil conditions permit, but sampling directly after fertilization or amendment application should be avoided.

  • Samples taken during the crop growth period will help in knowing the nutrient status of the soil in which plants are actively taking up nutrients.

  • It is important to sample at similar times year after year for comparing analysis at regular time intervals.

Evidence required:
For internal evaluation or research studies: Study protocol, data collection tools, dataset, report, laboratory analysis records
For external evaluation or research studies: Request for proposals (RFP) document, inception report, final report, dataset

Rationale: Soil is a non-renewable resource upon which mankind depends for survival, since the productivity of the soil determines what can be grown on and harvested from the soil. Soils vary greatly across the region ICARDA operates and the worldover. Soils have inherent weakness, primarily deficiencies in nutrients that are essential to crop cultivation across space and time, and hence the need to measure results related to this indicator. The insights generated from reported indicator values will help contextualize the observed crop productivities, inform the requisite interventions and help measure changes achieved through ICARDA's work on improving soil conditions.

Comments and limitations: