FERTILIZER APPLICATION

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FERTILIZER APPLICATION
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• What is fertilizer application?
• Fertilizers are used daily by farmers and
  families to help crops and gardens grow. Whether
  for a small garden of flowers and plants, or a
  large farm with thousands of acres of crops, a
  wide range of fertilizers have been developed to
  help different crops grow in different soil and
  weather conditions.

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Three Types of Pasture Species
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• 1. Frequency of defoliation in pasture species
• Defoliation is defined as a widespread loss of
  leaves or stripping of leaves on a plant. There
  are many things that can cause this, such as
  grazing animals like deer or rabbits, insect
  infestation, disease or chemical run off from
  herbicides.

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• 2 . Intensity of defoliation in pasture species
• Defoliation intensity treatments consisted of a
  range of percentage leaf area removal (0, 25, 50,
  75, or 100). These treatments were applied in
  parallel to a set of plants previously
  undefoliated, and to a second set of plants which
  had been defoliated several times at a constant
  height.

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• Impact of defoliation intensity and frequency on
  N uptake and mobilization

A (15)N tracer technique was used to
quantify N uptake, mobilization, and allocation
over a 7 d period. A significant reduction in
plant N uptake was observed with the removal of
more than 75 of lamina area, but only with high
N supply. As defoliation intensity
increased, the amount of N taken up and
subsequently allocated to growing leaves during
the labelling period was maintained at the
expense of N allocation to roots and adult
leaves.
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• Increasing defoliation intensity increased the
  relative contribution of roots supplying
  mobilized N to growing leaves and decreased the
  relative contribution of adult leaves.
  Defoliation frequency did not substantially alter
  N uptake, mobilization, and allocation between
  roots, adult and growing leaves on a plant basis.
  However, tiller number per plant was largely
  increased under repeated defoliation, hence
  indicating that allocation and mobilization of N
  to growing leaves, on the basis of individual
  tillers, was decreased by defoliation frequency.

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• Defoliation of broad-leaved
  Defoliation of grasses

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• 3. Morphological structure of pasture species
• The root morphology of ten temperate pasture
  species (four annual grasses, four perennial
  grasses and two annual dicots) was compared and
  their responses to P and N deficiency were
  characterized. Root morphologies differed
  markedly some species had relatively fine and
  extensive root systems (Vulpia spp., Holcus
  lanatus L. and Lolium rigidum Gaudin), whilst
  others had relatively thick and small root
  systems (Trifolium subterraneum L. and Phalaris
  aquatica L.).

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• Most species increased the proportion of dry
  matter allocated to the root system at low P and
  N, compared with that at optimal nutrient supply.
  Most species also decreased root diameter and
  increased specific root length in response to P
  deficiency. Only some of thRoot morphology was
  important for the acquisition of P, a nutrient
  for which supply to the plant depends on root
  exploration of soil and on diffusion to the root
  surface. Species with fine, extensive root
  systems had low external P requirements for
  maximum growth and those with thick, small root
  systems generally had high external P
  requirements.

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• These intrinsic root characteristics were more
  important determinants of P requirement than
  changes in root morphology in response to P
  deficiency. Species with different N requirements
  could not be distinguished clearly by their root
  morphological attributes or their response to N
  deficiency, presumably because mass flow is
  relatively more important for N supply to roots
  in soil species responded to N deficiency in this
  way.

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• Morphology and response of roots of pasture
  species to phosphorus and nitrogen nutrition
• The root morphology of ten temperate pasture
  species (four annual grasses, four perennial
  grasses and two annual dicots) was compared and
  their responses to P and N deficiency were
  characterized. 
• Root morphologies differed markedly some
  species had relatively fine and extensive root
  systems (Vulpia spp., Holcus lanatus L. and
  Lolium rigidum Gaudin), whilst others had
  relatively thick and small root systems
  (Trifolium subterraneum L. and Phalaris aquatica
  L.).

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•   Root morphology was important for the
  acquisition of P, a nutrient for which supply to
  the plant depends on root exploration of soil and
  on diffusion to the root surface. Species with
  fine, extensive root systems had low external P
  requirements for maximum growth and those with
  thick, small root systems generally had high
  external P requirements. 

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THATS ALL AND THANK YOU