Crop Estimate Cluster Count Method

Expand equal-probability sampled vine cluster counts to block yield with caller mature-cluster mass and count-sampling error only; no weight/selection uncertainty, harvest guarantee or optimum crop load.

Description

Randomly sampled vine cluster counts can be expanded to block yield using a supplied mature-cluster mass.

Randomly sampled vine cluster counts can be expanded to block yield using a supplied mature-cluster mass. Sampling error in counts is only one uncertainty source.^[1]

When to use Crop Estimate Cluster Count Method

Use this tool to expand equal-probability sampled vine cluster counts to block yield with caller mature-cluster mass and count-sampling error only; no weight/selection uncertainty, harvest guarantee or optimum crop load.

Prepare vineyard measurements, dates or block records for the intended growing period. Keep weights, counts and weather observations in the stated units.

How to use Crop Estimate Cluster Count Method and understand its results

Prepare vineyard measurements, dates or block records for the intended growing period. Keep weights, counts and weather observations in the stated units.
Enter randomSampleClusterCountsPerVine, representedBlockVineCount, callerMeanMatureClusterMassKg using the field table and calculation rules, then run the tool.
Read sampleMeanClustersPerVine, clusterMeanStandardErrorPerVine, modeledBlockYieldTonnes, clusterSamplingOnlyYieldStandardErrorTonnes. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
randomSampleClusterCountsPerVine	Random sample cluster counts per vine	list of number	Required
representedBlockVineCount	Represented block vine count	integer	Required
callerMeanMatureClusterMassKg	Caller mean mature cluster mass kg	number	Required

Use nonnegative integer counts and block size with positive cluster mass. Compute sample mean and sample-standard-deviation/√n, then scale both into yield and count-sampling-only standard error.^[2]

Sample variance requires at least two samples and uses the n−1 denominator.

yield tonnes = mean clusters/vine × block vines × cluster kg/1000

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
sampleMeanClustersPerVine	Sample mean clusters per vine	number
clusterMeanStandardErrorPerVine	Cluster mean standard error per vine	number
modeledBlockYieldTonnes	Modeled block yield tonnes	number
clusterSamplingOnlyYieldStandardErrorTonnes	Cluster sampling only yield standard error tonnes	number

json

{
  "input": {
    "randomSampleClusterCountsPerVine": [
      10,
      20,
      30
    ],
    "representedBlockVineCount": 100,
    "callerMeanMatureClusterMassKg": 0.2
  },
  "output": {
    "sampleMeanClustersPerVine": 20,
    "clusterMeanStandardErrorPerVine": 5.773502691896258,
    "modeledBlockYieldTonnes": 0.4,
    "clusterSamplingOnlyYieldStandardErrorTonnes": 0.11547005383792516
  }
}

Limitations and assumptions

Equal-probability sampling is assumed; cluster-mass and selection uncertainty are excluded.

Numbers and computed results must be finite; overflow produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Sample Bunch Weight Scaling Tonnage: Scale stratified measured bunch mass using caller known sample inclusion probabilities and actual represented bunch counts, explicitly Hájek weighted mean; not equal-weight count method, exact unbiased population total or random-sample claim. For a complementary task, use Lag Phase Weight Yield Forecast: Forecast heterogeneous lag-phase cluster masses using supplied calibrated maturity growth factors and represented cluster inventories; unlike count-only yield expansion, weight growth is explicit and not guaranteed.

Further background: Veraison to harvest: vineyard and winery considerations.

References

Veraison to harvest: vineyard and winery considerations — Penn State Extension
Crop Estimate Cluster Count Method — tool.io

Similar or alternative tools

Sample Bunch Weight Scaling Tonnage
Scale stratified measured bunch mass using caller known sample inclusion probabilities and actual represented bunch counts, explicitly Hájek weighted mean; not equal-weight count method, exact unbiased population total or random-sample claim.
Lag Phase Weight Yield Forecast
Forecast heterogeneous lag-phase cluster masses using supplied calibrated maturity growth factors and represented cluster inventories; unlike count-only yield expansion, weight growth is explicit and not guaranteed.