Specifications

2
for supporting crop water and nutrient management, but also to ob tain a descriptive, spatial
measure of the function and efficiency of these management systems. Researchers and
env ir on mental analysts are s earching for ways to increase spatial resolution of subsurface
soil properties to assist in characterizing and modeling below-ground processes in the large
(e.g., watersheds and basins).
1.2 Problem Definition
One method suggested by Morse and Kramberis is to use remote sens ing and satellite
imaging to infer the desired properties from pictures taken from low-earth orbit [2,3]. This
method is based on Evapotranspiration (ET) models and has received much attention d uring
the last twenty years. It has excelled in many areas like forest resource management, crop
yield estimation in precision agriculture, and analyzing the environmental effects of urban-
ization guiding city planners. However, it has produced little in terms of usefu l subsurface
property estimation in agriculture. The cost of access, infrequent access times, complexity,
and estimation error inherent to such appr oaches also deter agricultural pr oducers from
choosing this option. Researchers like Verhoest, on the other hand, have made use of this
technology but desire a more timely and reliable metho d. He claims that more ground data
is needed to continue refining their subsurface property estimation techniques [4].
The more common approach employed by producers and researchers alike involves th e
use of weather stations as a static means of collecting environmental data, and separately
paying for soil testing laboratories to examine the more elusive soil properties. A single
on-site weather station, similar to the one seen in fi g. 1.1, can cost thousands to tens
of thousands of dollars. These systems are also based on E T models and estimate the
amount of water in the soil from observable air characteristics. Due to the complexity of
these systems, most require experienced technicians trained to operate the measurement
equipment and manage extensive databases. In the ambit of academia, professors employ
students studying in technical fields to manage the complex field equipment used in their
research. The drawback for un iversities is that student turnover is very high and research
is put on hold to train new research assistants every one or two years.