Many of the small farms that dotted the countryside a hundred years ago had enclosures where horses, cows, and hogs were kept. The remnants from these enclosures impact soil properties today. Management that occurred on these farms 50 or even 100 years ago influences our ability to collect representative soil samples. Aerial photographs stored by USDA Farm Services Agronomy offices provide clues to past management. The objectives of this chapter are to (1) demonstrate the importance of considering the impact of human activities on collecting representative soil samples and (2) provide a data set that can be used as a GIS application for testing these concepts. The data set consists of data collected from a grid-soilsampled field located in South Dakota. Historical aerial photographs provide a view of prior uses of the land. A comparison between prior uses and current soil nutrient concentrations showed that when considering immobile soil nutrients like P and K, farmers and agricultural consultants need to realize that fields maintain a memory. Old homesteads should be sampled separately from the rest of the field. Other human-induced factors that should be considered include fence lines and rotational
sequence. Isolating areas impacted by historical management prior to soil sampling is paramount for developing reliable crop nutrient plans. Including samples from old homesteads may compromise the resulting fertilizer recommendation. Although not directly considered in this chapter, it is important to point out that soil properties, such as landscape position, pH, drainage, and soil texture, which are not directly impacted by man, also influence soil variability and soil test results.