Yield Mapping and Use of Yield Map Data

A yield frequency map depicting acorn and soybean rotation in Illinoisin a five-year period (from Franzen,2008). Each individual year did notshow all of these patterns. Meaningfullong-term trends in yield were revealedwith accompanying relationshipsto soil phosphorus, potassium andpH (acidity or alkalinity) levels onlyfollowing the combination of years.in the exact same manner. In this way, two years, threeyears or 20-plus years of data can be combined tocreate a more meaningful yield frequency map.The yield frequency map has been used as a zonelayer for revealing residual soil nitrate and other nutrientsin North Dakota. The yield frequency map also can helpreveal areas that require additional management, suchas a change in nitrogen application timing or a change indrainage if permitted. It can reveal the yield drag due tohedgerows, saline spots, compacted areas or locationscontaining harmful levels of sodium.The yield frequency map also can be usedconceivably to predict the relative performance of farmsand evaluate future production potential for renting orpurchasing decisions. If the soils on a farm that youmanage have a certain level of productivity, this potentialproductivity probably also is possible on farms withinseveral miles of that farm. This information can helpdetermine whether a farm is worth renting or buying.The yield maps are a valuable archive of fi eldperformance and the changes that management mighthave had on the fi elds. These archived maps and datacan be shared with bankers to help secure loans andwith future renters or purchasers of the land. They canbe passed down to the next generation so that the thingsgrowers learn about their fi elds will not be lost to theheirs.Many growers also use a yield monitor to helpdevelop nutrient strategies on specifi c farms. Differentrates of nitrogen, for example, can be applied in stripsacross soils within a fi eld, and the yields can help thegrower determine what the best rate might be for a soilor the fi eld. In addition, new products can be tested ona small strip within the fi eld and the effi cacy of their useYield frequencymap at Williston,N.D. (top), withlower yields onthe ridge slope(southeast tonorthwest direction)and higher yieldin the more levelareas above andbelow the ridgeslope (southwestand northeast)(elevation image onthe bottom).can be much more easily seen this way than by using aweigh wagon. The many data points of each strip alsolend themselves to the use of statistics offered withinspreadsheets to provide confi dence to the growerthat the differences seen were statistically real or not.Variability within a fi eld can mask differences or createdifferences unless statistics are used to help eliminatethe clutter.ReferencesSuddoth, 2007. Yield editor software. USDA-ARS. www.ars.usda.gov/services/software/download.htm?softwareid=20Franzen, 2008. Summary of forty years of grid sampling in twoIllinois fi elds. NDSU Technical Report.The NDSU Extension Service does not endorse commercial productsor companies even though reference may be made to tradenames,trademarks or service names.This publication may be copied for noncommercial, educational purposesin its entirety with no changes. Requests to use any portion of thedocument (including text, graphics or photos) should be sent to NDSU.permission@ndsu.edu. Include exactly what is requested for use andhow it will be used.For more information on this and other topics, see: www.ag.ndsu.eduCounty commissions, North Dakota State University and U.S. Department of Agriculture cooperating. North Dakota State University does not discriminateon the basis of race, color, national origin, religion, sex, disability, age, Vietnam Era Veterans status, sexual orientation, marital status, or public assistancestatus. Direct inquiries to the Vice President for the Division of Equity, Diversity and Global Outreach, 205 Old Main, (701) 231-7708. This publication will bemade available in alternative formats for people with disabilities upon request, (701) 231-7881.1M-12-08