Soil moisture in a crop's root zone must be regularly
monitored to accurately predict crop water requirements.
Most irrigation scheduling services currently
use the neutron probe to monitor soil moisture. Unfortunately,
there is a degree of variability associated
with use of the neutron probe creating uncertainty in
measurements of soil...
Improved water use efficiencies in irrigated agriculture are necessary to assist in coping with the accelerating demand and economic competition for the world's fresh water supply and increasing ecological concerns. This will likely rely in part on optimum irrigation, which implies regulated deficit irrigation. While conventional irrigation management is intended...
Potato ground cover and spectral data were measured
in the Columbia Basin during the 1990 growing season.
Three spectral were correlated with ground cover;
normalized difference, near infrared-red ratio, and the
first derivative of the spectral curve at 750 nm. All
models were statistically significant at the 99% level.
Normalized...
This study investigated the effect of plant surface
area (plant density) on the efficiency of organic carbon
removal in a bench-scale constructed wetland.
Constructed wetlands are commonly assumed to be biofilm
reactors in which organic carbon removal occurs primarily
through sedimentation and aerobic degradation by attached
microbial biofilms. In conventional...
Recycling of water in aquaculture facilities is used to minimize the amount of energy or tempered water required to control water temperatures. The rate of heat exchange between the water and the environment can be an important variable in the design, management, and economic analysis of a recycle system. A...
Nitrate contamination in ground and surface waters is of great concern to environmentalists. A two-dimensional model of water and solute movement in soils was used to test the usefulness and relative advantages of a two-dimensional model over a one dimensional model for analysis of deep percolation and nitrate leaching in...
Deliberately underirrigating a crop may yield economic
benefits. The optimal use of water by an irrigator
should be achieved under a deficit irrigation regime. It
is important to know how water deficits affect yields and
the interaction of the deficits with the scheduling of
irrigations.
A field experiment was conducted...
Under today's environmental conditions and with the increasing worldwide competition for water, errors in irrigation management decisions can be costly. Therefore, providing both accurate evapotranspiration estimation on a daily basis and estimation of the magnitude of error associated with this estimate is vital for informed water management decisions that allow...
The shallow aquifer in Northeast Malheur County, Oregon is polluted with Nitrates at concentrations exceeding federal drinking water standards. Efforts to solve the groundwater problems in this area have focused on developing farm management practices that will increase groundwater quality while maintaining agricultural production. Furrow irrigation is the dominant practice...
This study was prompted by the need for improving the efficiency of irrigation systems at the Oregon South coastal areas. Accurate information about evapotranspiration (ET) rates is essential for maximizing the efficiency of irrigation systems. Currently, ET estimates provided by Bureau of Reclamation AgriMet Program are derived from the Kimberly...
Furrow irrigation is the dominant practice for irrigating row crops in the western Treasure Valley region near Ontario, Oregon. Though improvements have been made in management practices over the years, excessive runoff and deep percolation are still important problems contributing to surface water and groundwater degradation. Field observations were made...
The intermittent or cyclic application of water to
furrows or borders, a method known as "surge flow irrigation",
can significantly improve the advance characteristics
of surface irrigation. Numerous field studies have
shown that the advance of furrows is considerably more
rapid when irrigated by surge flow than by the conventional,...
A growth model is developed for coho salmon which accounts for
temperatures and feeding rates typically encountered in fish hatchery
operation. Feeding rates utilized by the model ranged from
maintenance to maximum utilizable rations. The model is derived from
an empirical equation for maximum growth rate, and a theoretical
equation...
The rainfall regime of the Cape Verde Islands is influenced
by the Intertropical Convergence Zone (ITCZ) resulting in strong
seasonal trends and frequent thunderstorm events. These
events are frequently responsible for the destruction of riverine
structures and valuable crop land.
A menu driven database program (RIS) was developed for
the...
Often furrow irrigation application efficiencies are low compared to sprinkler systems. The primary goal of furrow irrigation is to infiltrate a relatively uniform target depth of water necessary for the crop, while minimizing the amount of runoff. The concept is difficult because water can infiltrate differently at all locations in...
Estimations of plant water use can provide great assistance to growers, irrigators,
engineers and water resource planners. This is especially true concerning the introduction
of a new crop into irrigated agriculture. Growing hybrid poplar trees for wood chip stock
and veneer production under agronomic practices is currently being explored as...