Organic Plant Production

Germination: Processes start in the seed, enzymes are activated, first root is 2mm

Emergence: Once you can see a part of the plant (above the soil)

Fast

- better competiveness against weeds
- fast resistance against pest and diseases
- homogenous plant stand

time periods can vary

tomatoes, rapeseed

~1/3 less in organic

e.g. wheat in EU 7-8t/ha in conv, 4-6t/ha in org.

A cross between two lines >> heterosis effects (higher yield)

sugar beet: - high input required (>> nearly no org.)

sugar cane: -lower sugar contens
- on the same field for several years (perennial)

total sugar yield is the same

the middle east

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1. Leaf develoment, tillering(, winter dormant)

2. Stem elongation

3. Booting (ear develoment in the stem)

4. Heading and flowering

5. Grain development

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amount of grains decreases (only the strongest tillers develop ears)

HI = harvested part (grains) / total above ground biomass

conventional:
- fat and short stem (applying stem shortener)
- big ears
- small rooting system (nutrients easily available)
- erectophil leafs

organic:
- longer stem (using the stem > straw, risk: lodging, reduce fungi/soilborn diseases)
- more planophil leafes >> weed suppression
- more space inbetween >> lower intrespecific competition
- wider root system >> better nutrient uptake
 

= leaf surface / ground area

for cereals ~8-10 before getting brown

erectophil = vertical (good for mixed cropping)

planophil = horizontal (weed suppression)

leaf cover x time

LAD= 300

= 100days LAI 3 or = 30days LAI 10 etc.

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Light Compensation Point = Respiration = Photosynthesis

Net Gas Exchange

<0 more respiration
>0 more photosynthesis
 

C4 can make better use of high light intensity

C4 higher optimum temp

C4 need higher CO2 levels

C3 beneficial in poor light conditions e.g. mixed cropping

A combination of crops in time and space.

monocropping: maize, wheat, rice

mixed/intercropping: milpa

ratoon cropping: crops that regrow e.g. sugar cane

mix of plant families (less diesease transfer), spring and winter varieties (weed suppression), N demanding and N supply

catch crops often mustard

Grass clover >> N

Winter wheat: high N demanding

Oat: less N demanding

Bean: N fixation

Spelt

farmyard manure >> Tiricale

Triticale + clover undersown

N fixation

3-4x cutting > fodder (fresh,silage), biogass, mulching

2-3 years >> avoid soil erosion (soil cover, priod of non till >SOM,soil sturcture), weed control (cutting)

- Seed costs
- compatibility with main crops
- cold hardiness/no cold hardiness
- fodder use
- time of sowing/growing duration

-reduce soil erosion (soil covered)
-take up N-surplus and thus reduce nitrate leaching
-preserve the soil structure
-reproduce soil organic matter (green manure)
-“feed" the soil organisms (earthworms, bacteria, fungi)

-Accumulation of nitrogen (symbiotic fixation by legumes + Rhizobia bacteria in root nodules)
-Weed control (i.e. perennial weeds, e.g. thistles)
-Improved soil structure
-By feed use for animals: results in manure (slurry, farm-yard manure)
-Reproduction of soil organic matter (below ground biomass)

•disease control, pest control, weed control
•crop residue (litter) management
•soil moisture and fertility utilization
•seed bed preparation
•sowing/planting and harvesting times
•Gross returns (economy)

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-improve or maintain soil fertility,
-supply nutrients (following crop use surplus of previous crop)
-control soil erosion,
-reduce the level of pests and diseases (mainly soil-born, harvest residues etc.)
-spread the workload on family labor, use of farm equipment, hired labor etc.,
-break reproductive cycles of pests and diseases,
-Annually changed environment for weeds: lower infestation
-mitigate risk of weather changes,
-less reliance on agricultural chemicals,
-stabilize yield,
-increase net profits

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Mineralization: Breakdown if organic matter >> nutrients/mineral compunds can be taken up by plants

Immobilization: Use by bacteria >> Minerals are not available for plants

 conv. 1-2%

org. 2-4%