Title: Legumes in Farming systems
1Legumes in Farming systems
- I. Papastylianou
- Senior Researcher
- Head Dept. of Horticulture
- Agric. Res. Inst./Cyprus
21st 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.)
3Historical 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
4- 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
5Symbiosis(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)
6Factors 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
7Methods 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
8Estimating 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
9- 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
10Formulas 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
11Long 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
12Amount 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
13Value of N2 fixation
- High protein products
- Fertilizer replacement
- Improvement of soil fertility
REDUNDANT
14R
NR
Productivity of barley in vetch-barley (VB) and
continues Barley (CB) systems under various N
fertilizer rates
15Role of legumes (in farming systems) for long
term sustainability
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