DATA - Self-thinning principle in reduced light and suboptimal nitrogen nutrition in miniature Brachiaria swards

This dataset contains the experimental data underlying the study Self-Thinning Principle in Reduced Light and Suboptimal Nitrogen Nutrition in Miniature Brachiaria Swards. The data quantify how light limitation (45% shade) and nitrogen deficiency (50 kg N ha⁻¹) alter the size–density compensation (SDC) mechanism, the leaf area index (LAI), orthogonal distance to the −3/2 self-thinning line, and dry-matter production of Brachiaria brizantha cv. Marandu maintained under constant canopy heights.

The dataset supports the evaluation of allometric shifts, morphological plasticity, productivity responses, and deviations from the theoretical Yoda’s −3/2 rule under controlled resource constraints.

Experimental design

The experiment followed a randomized block design with three replicates.

Factors:

Environmental condition (3 levels):

MA – Optimal: full light + adequate N (300 kg N ha⁻¹)

MA-N – Nitrogen deficit: full light + 50 kg N ha⁻¹

MA-L – Reduced light: 45% shade + 300 kg N ha⁻¹

Management height (4 levels):

12 cm, 24 cm, 36 cm, 48 cm

Sampling lasted 50 days (January–March 2023), with weekly cuts to maintain height and periodic destructive measurements of morphology and leaf area.

File

YODAIA.xlsx – Main analysis dataset
Contains all variables used for:

Log–log size/density regressions

LAI and morphological analyses

Orthogonal distance to the −3/2 line

Dry-matter production calculations

Nitrogen Nutrition Index (NNI)

Sheets and Variables
Sheet “Data” – Primary dataset (one row per environment × height × block)
Variable Description
Env Environmental treatment (MA, MA-N, MA-L)
Height Target sward height (12, 24, 36, 48 cm)
Block Experimental block (1–3)
TPD Tiller population density (tillers m⁻²)
TS (g) Mean tiller size (g tiller⁻¹)
LogTPD Base-10 log of TPD
LogTS Base-10 log of TS
LAI Leaf area index
SLA Specific leaf area (cm² g⁻¹)
R Leaf area:volume ratio per tiller
DM Cumulative dry-matter production (g DM m⁻² day⁻¹)
NNI Nitrogen Nutrition Index
Distance Orthogonal deviation from the theoretical −3/2 self-thinning line
Prod_rate Daily production rate (if included)
Units and data quality

Units are included in each column header.

All continuous variables were screened for completeness, consistency and outliers.

Logarithmic variables were computed only from positive values.

Shading structures were monitored for constant 45% light reduction; nitrogen applications were verified by mass balance.

Keywords

Self-thinning rule; Yoda’s law; allometry; size–density compensation; forage productivity; nitrogen limitation; light limitation; Brachiaria; functional traits; canopy structure.

Funding & acknowledgments

This dataset was generated within the doctoral research conducted at Santa Catarina State University (UDESC/CAV). Funding was provided by FAPESC (projects TR 1417, TR 813, TR 543).