Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)


This is the report of a preliminary investigation concerning the possibilities of estimating and forecasting wheat yields by an objective method of sampling the wheat crop as produced under farm conditions. The report gives a description of 1 year's work, using methods that are still in the experimental stage.

These investigations are based upon a sample taken in the eastern half of North Dakota just prior to the 1938 harvest.

The objectives of the sampling were to investigate:

1. The practicability of a route method of sampling the wheat crop to estimate and forecast yields per acre.

2. The amount of information that might be gained by the use of stratification in the sampling-by geographical division of the area sampled and the identification of the varieties in the samples taken.

3. The nature of the variation of yield among fields and the variation within fields and their relative magnitudes.

4. The kind of crop counts and measurements that may give the best basis for estimating and forecasting wheat yields, estimation being defined as the determination of the yield just prior to, or at, harvest time, while forecasting is considered as predicting the yield at some time previous to harvest.

5. The extent of the bias in the sampling.



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