Subsidy Transfer of resources to an entity, which either re-
duces the operating costs or increases the revenues of
such entity for the purpose of achieving some objective.
Subsistence Agriculture Agriculture carried out for the use
of the individual person or their family with few or no
outputs available for sale.
Sustainable Development Development that meets the needs
of the present without compromising the ability of future
generations to meet their own needs.
Sustainable Land Management (SLM) A system of tech-
nologies and/or planning that aims to integrate ecologi-
cal with socio-economic and political principles in the
management of land for agricultural and other purposes
to achieve intra- and intergenerational equity.
Sustainable Use of Natural Resources Natural resource
use is sustainable if specific types of use in a particular
ecosystem are considered reasonable in the light of both
the internal and the external perspective on natural re-
sources. "Reasonable" in this context means that all ac-
tors agree that resource use fulfils productive, physical,
and cultural functions in ways that will meet the long-
term needs of the affected population.
Technology Transfer The broad set of deliberate and spon-
taneous processes that give rise to the exchange and
dissemination of information and technologies among
different stakeholders. As a generic concept, the term is
used to encompass both diffusion of technologies and
technological cooperation across and within countries.
Terms of Trade The international terms of trade measures a
relationship between the prices of exports and the prices
of imports, this being known strictly as the barter terms
of trade. In this sense, deterioration in the terms of trade
could have resulted if unit prices of exports had risen less
than unit prices for imports. The inter-sectoral terms of
trade refers to the terms of trade between sectors of the
economy, e.g., rural & urban, agriculture and industry.
Total Factor Productivity A measure of the increase in total
output which is not accounted for by increases in total
inputs. The total factor productivity index is computed
as the ratio of an index of aggregate output to an index
of aggregate inputs.
Tradeoff Management choices that intentionally or otherwise
change the type, magnitude, and relative mix of services
provided by ecosystems.
Transgene An isolated gene sequence used to transform an or-
ganism. Often, but not always, the transgene has been de-
rived from a different species than that of the recipient.
Transgenic An organism that has incorporated a functional
foreign gene through recombinant DNA technology. The
novel gene exists in all of its cells and is passed through
to progeny.
Undernourishment Food intake that is continuously inad-
equate to meet dietary energy requirement.
Undernutrition The result of food intake that is insufficient
to meet dietary energy requirements continuously, poor
absorption,   and/or   poor   biological   use   of  nutrients
consumed.

Urban and Peri-Urban Agriculture Agriculture occurring
within and surrounding the boundaries of cities through-
out the world and includes crop and livestock production,
fisheries and forestry, as well as the ecological services
they provide. Often multiple farming and gardening sys-
tems exist in and near a single city.
Value Chain A set of value-adding activities through which a
product passes from the initial production or design stage
to final delivery to the consumer.
Virtual Water The volume of water used to produce a com-
modity. The adjective "virtual" refers to the fact that
most of the water used to produce a product is not con-
tained in the product. In accounting virtual water flows
we keep track of which parts of these flows refer to green,
blue and grey water, respectively.
The real-water content of products is generally negli-
gible if compared to the virtual-water content.
Waste Water "Grey" water that has been used in homes, ag-
riculture, industries and businesses that is not for reuse
unless it is treated.
Watershed The area which supplies water by surface and sub-
surface flow from precipitation to a given point in the
drainage system.
Watershed Management Use, regulation and treatment of
water and land resources of a watershed to accomplish
stated objectives.
Water Productivity An efficiency term quantified as a ration
of product output (goods and services) over water input.
Expressions   of   water   productivity.    Three   major   ex-
pressions  of water productivity can  be  identified:   1)
the amount of carbon gain per unit of water trans-
pired  by  the   leaf  or  by  the  canopy  (photosynthetic
water  productivity);   2)   the   amount   of water  trans-
pired   by  the  crop   (biomass  water  productivity);   or
3) the yield obtained per unit amount of water transpired
by the crop (yield water productivity).
Agricultural water productivity relates net benefits gained
through the use of water in crop, forestry, fishery, live-
stock and mixed agricultural systems. In its broadest
sense, it reflects the objectives of producing more food,
income, livelihood and ecological benefits at less social
and environmental cost per unit of water in agriculture.
Physical water productivity relates agricultural production
to water use—more crop per drop. Water use is expressed
either in terms of delivery to a use, or depletion by a use
through evapotranspiration, pollution, or directing water
to a sink where it cannot be reused. Improving physical
water productivity is important to reduce future water
needs in agriculture.
Economic water productivity relates the value of agricul-
tural production to agricultural water use. A holistic
assessment should account for the benefits and costs of
water, including less tangible livelihood benefits, but this
is rarely done. Improving economic water productivity is
important for economic growth and poverty reduction.