Legumes in Farming systems

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Legumes in Farming systems

• I. Papastylianou
• Senior Researcher
• Head Dept. of Horticulture
• Agric. Res. Inst./Cyprus

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1st document on the role of legumes in farming
systems

• Among the leguminous plants chick pea is the
  most soil exhausting, although this crop is in
  the ground only a very short time. Faba beans are
  not a burdensome crop to the ground, they even
  seem to manure it. People of Macedonia and
  Thessaly turn over the ground when faba is in
  flower
• Theophrastus (370-285 B.C.)

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Historical scientific roots of N2 fixation by
legumes

• Saussure, 1806
• Soil and not the atmosphere was the source of
  plant nitrogen
• Jean Baptiste Boussingault (French), 1838
• Legumes enriched the soil by introducing N from
  the air
• Lawes and Gilbert (British), 1850
• Confirmed Boussingault finding in Rothamsted
  in field experiments

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• Hellriegel and Wilfarth (German), 1880
• Legumes utilize atmospheric N2
• Legumes-microorganisms symbiosis
• Root nodules are the centers of N2 fixation
• Beijerinck, 1888 isolated the Rhizobium
  leguminosarum

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Symbiosis(S??ß???leaving together in harmony)

• Legumes offer carbohydrates
• Rhizobium offers nitrogen
• Legumes vs non legumes
• Lechemoglobin (O2 control)
• Nitrogenase
• Nitrogenase
• N2 NH3 amino acids
  proteins
• ATP
• H
• Low oxygen tension

(Courtesy of Oklahoma St. University)
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Factors affecting N2 fixation

• Presence of Bacteria
• Species by strain compatibility
• Survival of Bacteria
• Climatic factors temperature, light
• Soil factors nutrients availability (P, N, K,
  micronutrients), moisture, acidity
• Crop management Defoliation, competition, pest
  and pathogen control

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Methods of Estimating N2 fixation

• Lysimeter studies (Total N)
• Determines amount of N2 fixation
• 15N 1949 KamenGest (15N2), 1970 FriedBroeshart
  (A-value method)
• Determines percentage of N2. N2 x yield
  amount of N2 fixation
• Acetylene (1966, Dilworth)
• Determines rate of N2 conversion
• System approach (Papastylianou, Agronomy J. 1999
  329-334)
• Determines the total amount of N2 fixation

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Estimating N fixation within a system

• Variables needed
• S1n sum from Year 1 to Year n
• N2 Kg N fixed per year of legume
• n years of the study
• x number of phases in the cycle
• y portion of the legume in the rotation cycle
• Foliage Zone data
• L Kg N harvested legume tops
• F Kg N in tops of the harvested non-N2-fixing
  crop subsequent to legume
• M Kg in tops of the harvested non-N2-fixing crop
  grown in monoculture

Continued on next slide
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• Root Zone Data
• o Kg N in soil before the legume
• fl Kg N in soil after the legume
• fs Kg N in soil after the non-N2-fixing crop
  grown in rotation with the legume in phase-entry
  studies
• fm Kg N in soil after the non-N2-fixing crop
  grown in monoculture
• fls kg N in soil in the areas where the legume
  and non-N2-fixing crops were rotated in
  non-phase-entry studies

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Formulas used
Single year Crops

• N2L(fl-o)
• N2L-M
• N2 (L-M)(fl-o)-(fm-o)
• N2S1nL(fl-o)/n
• N2S1n(L-M) /n
• N2S1n(L-M) (fl-o)-(fm-0)/n
• N2S1n(L-M) (fl-fm)/n

Long-term monoculture
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Long term rotation systems

• N2S1n(LF)y(fl-o)(fs-o)/x/ny
• N2S1n(LF)(fls- 0)/ny
• N2S1n (LF) xM/n
• N2 S1n (LF) xMy(fl-o)(fs-o)/x-(fm-
  o)/ny
• N2 S1n(LF) xM(fls-o)-(fm-o)/ny
• N2 S1n (LF) xMy(fls-fs)/x-fm/ny
• N2 S1n (LF) xM(fls-fm)/ny

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Amount of N2 fixation

• N15 method vs. System approach method
• 50-200 Kg N/ha
• Average100 Kg N/ha
• Grain legumes-100 Kg N/ha
• Clover 150 Kg N/ha
• Contribution of legumes worldwide
• 250 000 000 ha (140 Kg N/ha fixed)
• 35 000 000 000 Kg N fixed worldwide

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Value of N2 fixation

• High protein products
• Fertilizer replacement
• Improvement of soil fertility

REDUNDANT
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R
NR
Productivity of barley in vetch-barley (VB) and
continues Barley (CB) systems under various N
fertilizer rates
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Role of legumes (in farming systems) for long
term sustainability
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