Crop Yield Interpretation for North Dakota: I. Sequential Sampling

Sequential sampling techniques were used to collect crop yield data to develop soil‐productivity indexes for soil interpretation in North Dakota. Hard Red Spring (HRS) wheat ( Triticum aestivum L.) data from four extensive agricultural soils in three northeastern counties are presented to illustrate the procedure and application of results. Soils on concave landscape positions that received runon surface water had the highest average yield and greatest range in yield. Soils on convex upper slopes had significantly lower yield than soils on other landscape positions. Results were generally comparable to current productivity estimates. Data relating A‐horizon thickness to yield indicated an average increase in yield of 1.79 bu/acre for each inch of A horizon. Sequential sampling proved to be an efficient means of collecting data for soil‐crop yield interpretation.