Presentation on theme: "STAND ESTABLISHMENT: Influencingfactors ATMATM Frank J. Dainello, PhD Ext. Horticulturist Com. Veg. Crops Dept of Hort. Sci."— Presentation transcript:
STAND ESTABLISHMENT: Influencingfactors ATMATM Frank J. Dainello, PhD Ext. Horticulturist Com. Veg. Crops Dept of Hort. Sci.
STAND ESTABLISHMENT “the sins of planting will haunt you all season” “the sins of planting will haunt you all season” Anonymous A thought worth remembering!!
3 Phases of Established n 3. Seedling establishment STAND ESTABLISHMENT 1.Seed bed preparation/planting 2. Seed germination & emergence
Establishment –Phase I n STAND ESTABLISHMENT 1.Seed bed preparation/planting
SEEDBED PREPERATION “The facet of stand establishment stand establishment in which the greatest sins are committed!”
SEEDBED PREPERATION The seedbed is to the crop as the foundation is to the houseThe seedbed is to the crop as the foundation is to the house Improper preparation leads to uneven emergence, lack of uniformity of stands, weed and pest problemsImproper preparation leads to uneven emergence, lack of uniformity of stands, weed and pest problems Reduce yieldReduce yield Increased production costIncreased production cost
SEEDBED PREPERATION Year round undertaking –Employ practices to enhance tilth and structure Immediate crop destruction Keep weeds under control Build organic matter Pay attention to rotations
SEED PLACEMENT IMPACTS STAND ESTABLISHEMT IMPACTS STAND ESTABLISHEMT Lateral placement Depth placement TOO DEEP: TOO DEEP: Increased soil impedance pressure Increased soil impedance pressure reduced gas exchange risk of water logging and or crusting effect TOO SHALLLOW: risk of insufficient moisture for imbibition risk of high temperature injury Depth: 3 times the seed width PLANTING
OVER SEEDING CAN CAUSE PROBLEMS WITH UNIFORMITY/QUALITY Poor in-row spacing
GERMINATION The process by which a viable(living) seed imbibes water, triggering respiration, protein synthesis and other metabolic activities which cause radicle emergence.The process by which a viable(living) seed imbibes water, triggering respiration, protein synthesis and other metabolic activities which cause radicle emergence.
GERMINATION Seeds are considered to have germinated once radicle emergence has occurred Germinated seed (Radicles emergenced)
SEED MOISTURE CONTENT Seeds stored 4 - 5 % moisture contentSeeds stored 4 - 5 % moisture content Water needed to active metabolic processesWater needed to active metabolic processes Excess moistureExcess moisture –inhibits gas exchange(stops metabolic processes) –leakage of sugars, organic and amino acids –increase pathogen susceptibility(substrate)
Oxygen & Gas Exchange Seeds are living organisms. Oxygen needed in metabolic process for germination to occur in vegetables Water logged soils force oxygen out of soil microclimate and stops processes –can cause physiological breakdown –decay as a result of pathogenic attack
Moisture & Germination Moisture stress –The greater the deficit the slower the germination and radicle emergence –Greater negative effect on seed with poor vigor More advanced germination the greater the impact of moisture stress –some evidence for cycling wetting and drying prior to planting enhances germination.
GERMINATION (Soil physical properties) Soil moisture content Soil temperature Soil insect and disease pressure Soil impedance
FACTORS IMPACTING GERMINATION & EMERGENCE Soil temperature
TEMPERATURE & GERMINATION Generally the higher the temperature the better the germination for most vegetablesGenerally the higher the temperature the better the germination for most vegetables –warm temperatures increases respiration rate and other metabolic processes Each species has an optimum temperature range above or below which germination is reduced or inhibitedEach species has an optimum temperature range above or below which germination is reduced or inhibited –temperature impact pathogen activity which can have a detrimental effect on germination
SOIL TO SEED CONTACT Onset of germination delayed at soil matrix potentialsOnset of germination delayed at soil matrix potentials Highest germination % between -0.3 & -0.1Highest germination % between -0.3 & -0.1 Soil matrix potentials outside of this range – DELAYED GERMINATIONSoil matrix potentials outside of this range – DELAYED GERMINATION
SOIL TO SEED CONTACT Germination ultimately determined by: –the impedance of the soil matrix due to surface and colloidal forces –the contact of the seed with soil moisture irrespective of the initial difference between the water potential of the seed interior and the soil
SOIL FACTORS IMPACTING GERMINATION & EMERGENCE Soil impedance – the pressure or barrier effect soil has on emergence.
SOIL IMPEDANCE Emergence force of seed hypocotyls will determine how effective a specie is in over coming the negative effect of soil impedance.Emergence force of seed hypocotyls will determine how effective a specie is in over coming the negative effect of soil impedance. Small seeded crops such as carrots lack good emergence forceSmall seeded crops such as carrots lack good emergence force Crust and/or deep planting very disastrous to crops lacking good emergence forceCrust and/or deep planting very disastrous to crops lacking good emergence force
EMERGENCE VIGOR The ability of a hypocotyls to rapidly emerge through the soil profile and emerge above the soil surface.
Establishment- Phase III Seedling establishment PHASE 3
SEEDLING ESTABLISHMENT The time from seedling emergence from the soil until 2 – 4 true leaf stage Impacted by »Insects »Diseases »Soil moisture and temperature »Wind Desiccation »Sand basting »Hail »Chemical injury
STAND ESTABLISHMENT GOAL TO REDUCE THE TIME REQUIRED FOR SEED GERMINATION TO SEEDLING ESTABLISHMENT
n 3. Seedling establishment STAND ESTABLISHMENT 1.Seed bed preparation/planting 2. Seed germination & emergence
3 COMPONENTS OF STAND ESTABLISHMENT 1.Good Soil Conditions 2.Viable Seeds 3.Favorable Microclimate
IDEAL SEED BED SOIL CONDITIONS Well pulverized Free of clods and plant residue Firm and level Provide good soil to seed contact
MEANS of ACHIEVING GOOD SOIL to SEED CONTACT Ovoid working soil when wetOvoid working soil when wet Ovoid excessive disking, causes compaction restricts root growth & yieldOvoid excessive disking, causes compaction restricts root growth & yield Pulverize soil to the point that it is free of clods and debrisPulverize soil to the point that it is free of clods and debris –Rotovators are ideal implements
SEEDS Embryonic or New plantsEmbryonic or New plants –plant in miniature - Contained in a Dispersing structuresContained in a Dispersing structures –protected in a cover (the seed coat) until a self sufficient autotrophic organism can be established
VIABLE SEED Seed Having The Ability To Germinate and develop into a seedling once planted!Seed Having The Ability To Germinate and develop into a seedling once planted!
FACTORS INFLUENCING SEED VIABILITY 1.Seed coat (testa) 2.Food reserves 3.Dormancy 4.Condition under which seed produced 5.Storage conditions
SEED COAT CHARACTERISTICS SEED COAT CHARACTERISTICS Surface area Nature of the surface Mucilage content Thickness Porosity
Thickness or Porosity – can impede water uptake – restrict radicle emergence – impact gas exchange These then interact to slow or stop respiration and other metabolic processes associated with germination
SEED FOOD RESERVES Quantity determined by the quality of the seed crop –Growing conditions –Harvest –Storage
CONDITIONS UNDER WHICH SEED CROP IS GROWN Stressed plants are weak plants which in turn produce unviable or poor germinating seed
SEED DORMANCY The failure of seed to germinate even under apparently favorable conditions –Due to a inherent blocking mechanism within the seed