The Evolution of Spectral Sensing and Advances In Precision Turfgrass Management.

Since the advent of agriculture, sites have been predominantly managed in a homogenous, uniform manner.  Plant growth and yield, however, typically vary significantly within a relatively small area because of the dynamic interactions of climatic, plant, and soil factors.  A focus on increasing input efficiency and implementing more environmentally conscious practices has occurred in the agriculture industry over the past 20 years.  The concepts of precision agriculture (PA) and more recently precision conservation (PC) have been the driving forces behind research geared toward maximizing efficiency and addressing environmental concerns.  As a corollary to PA and still in its infancy, the concept of precision turfgrass management (PTM) is gaining momentum as an approach to a greater degree of micromanagement involving resources (e.g., water, amendments, labor, energy, etc.) for efficient irrigation, salinity, nutrient, pest, and cultivation management.  Golf courses, athletic fields, and other complex sites do not exhibit uniform conditions.  There is normally a significant degree of spatial variability that creates a number of microclimates, or site-specific management units (SSMUs) that have variable input requirements.  PTM utilizes intensive soil and plant site assessment to acquire detailed information for more precise, responsible, and efficient management than what is currently conducted.  In 1998 and 1999, a vehicle-mounted optical sensor was used to map turf canopy NDVI on a creeping bentgrass (Agrostis stolonifera L.) golf course putting green.  The maps based on NDVI highly correlated (r² = 0.98) to plots fertilized with varying N rates, as the turf response and cover mimicked the spatial maps.  Poor nutrition, sparse turf cover, and some irrigation patterns were revealed by the maps.  NDVI mapping could reduce fertilizer and pesticide use, increase turf uniformity, and potentially provide an early warning system for turfgrass managers.  In this chapter, PTM is used to denote a concept or approach toward a greater degree of site-specific management than the current practice.  Increasing efficiency, including resource sustainability, is of greater importance than the economic aspects.  The “key factor” for the turfgrass industry is that the only means of achieving increased input application efficiency on a site is by practicing a greater degree of site-specific management – which in turn requires that we develop better means to obtain up-to-date, site-specific, spatial and temporal information in order to make wise decisions.  Thus, these challenges must be addressed as a natural progression in turfgrass management and science.