Delineating crop management zones in small fields using multitemporal Landsat data

Remotely sensed imagery data are widely used for monitoring crop growth and prescribing management practices. However, acquiring multiple images throughout the growing season for several years could be cost prohibitive. Moderate spatial (30m) resolution Landsat data could be a potential source for accomplishing these objectives. While delineating within-field management zones in large fields using Landsat data is well documented, fewer attempts have been made in smaller fields because of the restrictions imposed by the spatial resolution. On the other hand, Landsat data are acquired once every 16 days which increases the possibility of obtaining several images in a growing season. Landsat spectral bands are rigorously calibrated enabling multi-year comparison. This paper reports on the utility of multi-year Landsat images for monitoring crop growth and delineating management zones in small fields in Wyoming ( USA). Spectral reflectance values derived from Landsat images acquired in each growing season were converted to vegetation indices. Based on these values the pixels within the field were grouped into low, medium and high growth classes. Using multi-year growth patterns, crop management zones were delineated for each field. Results from this study could provide valuable insights for farmers to identify problem areas within their fields and better manage them.