Water is finite on earth. There is a fixed amount of water which neither decreases or
increases. Fresh water is a renewable resource because of the water cycle. From a human
perspective the source of freshwater is rainfall. Most of this rainfall is used directly for
vegetative growth, such as natural vegetation, pasture, rain-fed maize etc. This process,
known as transpiration, is highly productive and produces in Southern Africa the bulk of
It is widely accepted that irrigation allows for the increase and stability in agrarian
yields, being a necessary tool to support food supplies and necessities for certain raw
materials in the world. However, irrigated agriculture is also considered the most
significant fresh water consumer and one of the main causes of pollution, degradation
and depletion of natural resources. These impacts are primarily related to changes in
the water cycle, salinization of agricultural soils, and salinization and pollution of
water resources due to the use of agrochemicals....
Measurement of efficiency started with Farrell (1957) who, following Debreu (1951)
and Koopmas (1951), proposed a division of efficiency into two components: technical
efficiency, which represents a firm’s ability to produce a maximum level of output from
a given level of inputs, and allocative efficiency, which is the ability of a firm to use
inputs in optimal proportions, given their respective prices and available technology.
The combination of these two measures yields the level of economic efficiency.
As we noted in our October 1990 report on nonpoint source pollution,
obtaining data on this type of pollution is especially problematic and
costly because the sources are diffuse and the pollution from these
sources can be episodic, Project officials have been able to offset this
problem, to some degree, by ensuring that any trades clearly result in
water quality improvements. Under the DilIon Reservoir project, for
example, point source dischargers earn 1...
But what happens if interest rates unexpectedly rise
by a significant amount, say 4 percentage points
across the yield curve? Such a move has happened
only twice in the United States, once in 1980 and
again in 1981, as the Federal Reserve drove interest
rates higher in an effort to combat high inflation. But
in relative terms, if interest rates jumped from 2.9%
to 6.9%, that rise would constitute a 140% change
in rates—a change that has never occurred in the
United States, and one that would be truly significant.
The use of industrially manufactured nitrogen (N)
fertilizers increased rapidly in developed countries
between 1960 and 1980. This facilitated a large increase
in the production of feed and food grains (maize, wheat,
and rice) per unit of cultivated land, but in some regions it
also contributed to enrichment of surface and groundwater
with various forms of nitrogen. Fertilizer, however, is not
the only source of nitrogen that can cause contamination of
Nowadays, environmental issues including air and water pollution, climate
change, overexploitation of marine ecosystems, exhaustion of fossil resources,
conservation of biodiversity are receiving major attention from the public,
stakeholders and scholars from the local to the planetary scales. It is now
clearly recognized that human activities yield major ecological and environ-
mental stresses with irreversible loss of species, destruction of habitat or cli-
mate catastrophes as the most dramatic examples of their eﬀects.
IN BOTH NATURAL AND AGRICULTURAL CONDITIONS, plants are frequently exposed to environmental stresses. Some environmental factors, such as air temperature, can become stressful in just a few minutes; others, such as soil water content, may take days to weeks, and factors such as soil mineral deficiencies can take months to become stressful. It has been estimated that because of stress resulting from climatic and soil conditions (abiotic factors) that are suboptimal, the yield of field-grown crops in the United States is only 22% of the genetic potential yield (Boyer 1982).
In this section we look at data concerning 10-year government bond yields. Although
our main interest is the default risk, this presents only one channel through which
fiscal policies can affect long-term yields. There are other channels operating through
monetary-fiscal interaction, which should be reflected in the evolution of yields.
Therefore we start our descriptive analysis in this section by looking at yields,
forward rates and inflation expectations at a weekly frequency. Then we move to an
analysis of interest rate swap spreads, at a weekly and daily frequency.
Information -- or more precisely, better information -- can be viewed much like any
other commodity in that it is costly to acquire and provides benefits to the user. The goal is to
identify the kinds of situations in which improvements in data or methods are likely to yield
the greatest net benefit. From an economic standpoint, information itself has little intrinsic
value. Instead, information acquires value when it facilitates optimizing behavior. That is,
better information can lead to changes in actions, changes that themselves create value.
Coverage levels that are higher than CAT are called “buy-up” or “additional” coverage.
additional premium paid by the producer, and partially subsidized by the government, a producer
can “buy up” the 50/55 catastrophic coverage to any equivalent level of coverage between 50/100
and 75/100 (i.e., up to 75% of “normal” crop yield and 100% of the estimated market price). In
limited areas, production can be insured up to the 85/100 level of coverage.
APH policies account for more than 90% of yield-based policies sold.
What have been the impacts of the GGDP-generated maize technologies? In the absence of reliable baseline data, it was not
possible to calculate quantitative measures of project impact. Based on farmers’ qualitative judgments, however, it is clear that
adoption of the GGDP-generated technologies has been associated with significant farm-level productivity gains (measured
in terms of maize yields) and noticeable increases in the income earned from sales of maize. Impacts on the nutritional status
of rural households, however, appear to have been less pronounced.
The Water Quality Act of 1965 (WQA) was the first major statutory attempt to address
the nation’s growing water quality problems. The Act proved to be a weak basis for enforcement
authority, but did yield one major improvement: the development of ambient water quality
standards. States were called upon to set their own standards and given flexibility to determine
how standards would be met. The Act’s major weakness was that it gave no concrete authority
to force effluent reductions by specific polluters.
In the late 1980’s, a considerable amount of research addressing the
effects of acidic deposition was begun, much of it related to the Congressionally
mandated National Atmospheric Precipitation Assessment Program
(NAPAP). As a result of the 10-year NAPAP program, effects on human
health, materials, structures, visibility and terrestrial and aquatic ecosystems
were evaluated. As a result of NAPAP funded research, negative effects of
acidic deposition were documented on freshwater lakes in the Adirondacks
and on the red spruce of the Adirondacks and northern Appalachians....
How, now, are these remarks to be applied in such a way as to yield an account of our
aesthetic pleasure in some more sophisticated aesthetic object such as a dramatic work? We are
confronted, first of all, by a manifold of actions on the stage. These provoke involvement: the
aesthetic enjoyment of a drama would seem indeed to rest on a peculiar sort of `comfortable
sympathy' with the characters we perceive (cf. 151). But they provoke also empathy-feelings,
which are however experienced as phantasy-material only. And now these two sorts of feelings
Moisture deficiencies occurring early in the crop cycle
may delay the maturity season and reduce yields.
Shortages later in the season often lower quality, as
well as yields. However, irrigation surplus, especially
late in the season, can reduce both the quality and the
post-harvest life of the crop.
Uneven or surplus irrigation, above the amount
required to replace evapotranspiration, causes nitrate
leaching below the root system and the ability of
the crop to recover from the nitrogen deficiency
Aldosterone: Enhances Na+ reabsorption at the collecting duct of the kidney Aneuploidies: Abnormal numbers of chromosomes that may occur as a consequence of abnormal meiotic division of chromosomes in gamete formation Antidiuretic hormone (arginine vasopressin): Acts to conserve water by increasing the permeability of the collecting duct of the kidney Blastocyst: At the 8- to 16-cell stage, the blastomere develops a central cavity and becomes a blastocyst. The cells on the outer layer differentiate to become trophoblasts. ...
The World Bank‟s green bonds have been well received by investors since they were structured to
have simple and standard financial features, such as equivalent credit quality and yield levels to other
World Bank triple-A rated bonds so that there is no sacrifice to the end-investor in terms of returns. They
were also issues into a liquid market and can be as easily traded as other „plain vanilla‟ bonds issued by the
A seeder should place seed in an environment for reliable germination. The main objective
of sowing is to put seeds at a desired depth and spacing within the row. Uniform seed
distribution within the soil result in better germination and emergence and increase yield by
minimizing competition between plants for available light, water, and nutrients. A number
of factors affect seed distribution in soil. Seed metering system, seed delivery tube, furrow
opener design, physical attributes of seed and soil conditions all play a part in determining