The prevailing low food production in sub-Saharan Africa is an issue of
great concern especially since Africa south of the Sahara is the only remaining
region of the world where per capita food production has remained stagnant. This
chapter reviews long-term experiments in Africa in the context of shifting paradigms
related to tropical soil fertility management from fi rst external input paradigm right
through to the current Integrated Soil Fertility Management (ISFM) approach,
which is a culmination of the participatory methods developed along the paradigm
This book is a response to that need for a synthesis. It contains 17 chapters, each prepared by authors who are internation- ally recognized for their knowledge and expertise in a particular area of soil/plant biology.
Abiotic stresses are serious threats to agriculture and the environment which have been exa‐
cerbated in the current century by global warming and industrialization. According to FAO
statistics, more than 800 million hectares of land throughout the world are currently salt-af‐
fected, including both saline and sodic soils equating to more than 6% of the world’s total
land area. Continuing salinization of arable land is expected to have overwhelming global
impact, resulting in a 30% loss of agricultural land over the next 25 years and up to 50% loss
“Be it deep or shallow, red or black, sand or clay, the soil is the link between the rock
core of the earth and the living things on its surface. It is the foothold for the plants we
grow. Therein lays the main reason for our interest in soils.” --- Roy W. Simonson,
USDA Yearbook of Agriculture, 1957.
The British naturalist Charles Darwin (1809–1882) was probably the first scientist to
examine a soil profile and suggest factors responsible for the structure of the various
The same amount of water has been present on our planet for about 4 billion years, since shortly after the Earth was formed. Since then it has cycled through evaporation, condensation, precipitation and surface runoff multiple times. Water scarcity as an abiotic factor ranging from moderate to severe stress levels, accompanied by loss of moisture in the soil, is extremely hard for most organisms to cope with, particularly terrestrial plants and their food-chain dependents.
The papers in this book provide new information on several aspects of soil erosion
and applications of the National Resources Inventory (NRI). They were commissioned
following a planning workshop in July 1984 and were presented in December 1984
during a national convocation, “Physical Dimensions of the Erosion Problem.” The
workshop and convocation were held by the National Research Council's Board on
Agriculture in response to a request from the Soil Conservation Service of the U.S.
Cancers of the endometrium, ovary and cervix share
certain characteristics. However, etio-pathogenesis of all
the gynecological malignancies is yet to be explored. Even
though the etiologic factors are generally environmental,
the exact cause of each gynecological cancer is not known
(Senate Community Affairs References Committee,
Commonwealth of Australia, 2006). Worldwide, cancer
incidence rates vary widely between different geographic
regions and ethnic groups.
Hydrogen peroxide is particularly effective when it reacts with ferrous iron
) to produce Fenton's Reagent. Ferrous iron may be naturally present in the
subsurface soils and/or groundwater, or it can be added as a catalyst solution
together with the hydrogen peroxide to produce this aggressive chemical reaction.
Hydrogen peroxide in the presence of ferrous iron (Fe2+
) reacts to form
hydroxyl radicals (OH•), ferric iron (Fe3+
), and hydroxyl ions (OH-
). The hydroxyl
ions are very powerful oxidizers, and react particularly with organic compounds.
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....
Next, we examine predictability in both benchmark returns and fund risk loadings.
Consider the dogmatist who believes in such a predictability structure (PD-2). This
investor would experience a nontrivial utility loss of 15.1 basis points per month (1.8%/
year) in December 2002 if forced to hold the optimal portfolio of the ND. The utility loss is
even larger over the course of all 276 monthly investments. This loss averages 21.1 (39)
basis points per month over expansions (recessions).
Hedge funds increased in value to €79 billion, driven largely by revaluations of €2.2 billion
amid a net transactions outflow of €0.3 billion. The revaluation performance was tempered
by the fact that some hedge funds assumed short positions in a positively performing market.
Hedge funds have not outperformed other investment strategies in the year to date.
Other funds, comprising mostly mixed funds
, experienced negligible inflows of €0.2 billion,
despite positive revaluations of €5.1 billion, culminating in an increase in overall stock to
€152 billion. ...
As minister responsible for human settlements
issues in the Norwegian Government, I want to
underline the responsibility of governments to take
active action to improve the living conditions of the
underprivileged in society. In Istanbul we reaffirmed
our commitments to the full and progressive realisa-
tion of the right to housing and recognised an obliga-
tion by Governments to enable people to obtain
shelter and to protect and improve dwellings and
neighbourhoods. Now – five years later – we still have
a long way to go.
This survey was completed via the internet from January 7 to February 20, 2008 by 253
individuals who served on at least one audit committee for a publicly traded company in
2007. Some respondents were also given the option to complete a paper and pencil survey in
place of the online survey to increase response rate.
While conducting a probability sample with audit committee members is technically possible, it
was not feasible from a cost or time standpoint.
There are 4 million miles of roads in the United States. One hundred
years ago, roads were primarily unpaved and had half the number of
miles of the present U.S. road system. As the system grew, roads became
wider and more complex structurally to provide for more and heavier
traffic. New construction technology and greater structural stability
were needed to improve the road system.
All phases of road development—from construction and use by vehicles
to maintenance—affect physical and chemical soil conditions, water
flow, and air and water quality.
There has also been recent interest in and some field applications using sodium
persulfate (Na2S2O8) to oxidize organic contaminants or to reduce the oxidant
demand of native soils before other oxidants are applied to the contamination.
Some research has demonstrated that when mixed with ferrous iron as a catalyst,
the sulfate free radical (SO4
) can be produced, which has an oxidation potential
only slightly less than Fenton's Reagent. Field testing of this oxidant to date has
primarily involved the destruction of chlorinated organics rather than petroleum
The Guest Editors of this volume agreed in advance on the order listed on the title page, although equal editorial effort
should be recognized. Vadim Birstein, Robert Boyle and John Waldman convened the 1994 conference that was the source
for the original drafts of most of the manuscripts included in this collection. William Bemis put the volume in final shape;
he is also responsible for safeguarding the standards of all contributions as the editorial representative of Environmental
Biology of Fishes.
Decreases in pH and ANC are often paral-
leled by changes in element concentrations
including increases in Al
decreases in Ca
. High dissolved Al
trations can have toxic effects on many types of
aquatic biota, and at extreme levels few aquatic
species can survive (Table 1). Organic forms of
are much less toxic than inorganic forms.
Emerging research suggests that Ca
tions in streamwater are also an important bio-
Providing the board conducted one, the previous year’s executive performance eval-
uation most likely includes an action plan for the current year, with developmental
goals for the executive. Include these in the evaluation; if not attended to, an excel-
lent reason needs to be provided.
The executive job description should list major areas for which the executive is respon-
sible. It’s essential that the board review this in preparation for the job evaluation, espe-
cially if your board has never evaluated its director.
Species mixtures are often recommended over single-
species cover crops or sod crops because the mixtures tend to
use resources more fully and provide a more diverse habitat.
Except in situations where a legume would not establish
well, or where the nitrogen-fixing power of legumes is not
desired, at least one legume and one non-legume are recom-
Some growers establish a sod-forming crop between
rows of a cash crop, forming a living mulch which provides
soil-improving benefits without taking land totally out of
Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Diﬀerential photosynthetic and survival responses to soil drought in two evergreen Nothofagus species...