LEAF LITTER STUDY AND EFFECTS OF ERTILIZATION ON TREE GROWTH

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LEAF LITTER STUDY AND EFFECTS OF ERTILIZATION ON
TREE GROWTH

• Dave A. Mays
• Alabama AM University
• Normal, AL 35762

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Question?

• How much leaf litter has accumulated under six
  year old sweetgum trees and what is its
  composition?

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PROCEDURE!

• Total litter collection from one-square meter
  area at two places in each plot
• Dry matter yield and chemical composition of
  litter determined by standard means

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• Effects of nitrogen on leaf litter accumulation
  and
• composition
• Parameters Trees N Trees - N
• Yield, mT ha-1 12.5 8.7
• Organic C 22.4 22.1
• Nitrogen 1.07 1.04
• Phosphorus 0.054 0.045
• Potassium 0.11 0.11
• Calcium 2.9 2.8
• Magnesium 0.23 0.25

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• Effects of nitrogen on yield of sweetgum leaf
  litter
• constituents, kg ha-1
• Constituents Trees N Trees - N
• Organic C 2828.0 1916.0
• Nitrogen 133.1 89.8
• Phosphorus 7.0 4.2
• Potassium 13.3 9.5
• Calcium 366.0 252.0
• Magnesium 29.8 21.5

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• Effects of cover crop species on sweetgum leaf
• litter yield and composition
• __________________________________________
• Parameter No Tall Crimson
• Cover Fescue Clover
• __________________________________________
• Yield (mT ha-1) 12.3 11.1 11.2
• Organic C 22.9 24.7 27.6
• Nitrogen 0.82 0.83 1.02
• __________________________________________

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• Effects of cover crop species on yield of leaf
• litter constituents
• __________________________________________
• Constituents No Tall Crimson
• Cover Fescue Clover
• __________________________________________
• Organic C 2879 2757 3012
• Nitrogen 105.1 92.1 114.1
• __________________________________________

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• Effects of Cover crop and prior fertilization on
• tree size in 2000.
• __________________________________________
• Treatment Height(m) DBH(cm) VI(cc)
• T C N 6.6 7.5 37712
• T C - N 5.6 6.9 26247
• T - C N 6.5 8.1 42022
• T - C - N 5.4 6.7 23908
• __________________________________________
• T Trees C Cover N Nitrogen

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Effects of Fertilizer on Tree Height
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Effects of Fertilizer on Tree Diameter

• Ground-line was used as Diameter from 1995 - 1997
• DBH was used as Diameter from 1998 - 2000

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Effects of Fertilizer on Volume Index

• Ground-line was used as Diameter from 1995 - 1997
• DBH was used as Diameter from 1998 - 2000

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• Effects of Cover crop and N fertilization on N
• Concentration in sweetgum leaves, July
• 2000.
• _______________________________________
• Treatment N Concentration
• Trees Cover N 1.55
• Trees Cover - N 1.09
• Trees - Cover N 1.54
• Trees - Cover - N 1.22
• _______________________________________

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• YIELD OF SWITCHGRASS kg ha-1
• ______________________________________
• Year Cut 1 Cut 2 Total
• ____________________________________________
• 1995 4446 ---- 4446
• 1996 4430 4000 8430
• 1997 8637 3926 12563
• 1998 7692 2453 10145
• 1999 5306 2998 8304
• 2000 4437 ---- 4437
• 2001 8270 5444 13714
• ___________________________________________
• N 1995 - 2000 _at_ 120 kg ha-1 2001 _at_ 200 kg ha-1

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• Soil Analysis 0-6 in, April 2000
• ___________________________________________
• Crop pH P K Ca Mg
• ___________________________________________
• Corn 5.8 35 135 1900 270
• Switchgrass 5.1 30 77 1135 134
• T C N 5.4 23 150 1165 170
• T C N 5.3 14 175 1140 174
• T - C N 5.3 28 117 1190 182
• T - C - N 5.5 14 145 1205 208
• ___________________________________________

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• NEEDS
• 1. Better chemical weed control
• Complete control in flat areas for 2 or 3 years
• Strip control in sloping areas. Use weeds for
  cover in center of plot instead of fescue and
  control weeds in tree rows
• As an alternative use reseeding crimson clover in
  middles

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• NEEDS
• 2. Better control of fertility fertilizer around
  trees for 2 or 3 years rather than broadcast
  fertilization.
• 3. More emphasis on machinery development to
  apply herbicides and fertilizers in an
  agronomically sound and economically efficient
  manner.