STAND ESTABLISHMENT: Influencing factors

1. STAND ESTABLISHMENT: Influencing factors Frank J. Dainello, PhD Ext. Horticulturist Com. Veg. Crops Dept of Hort. Sci. ATM

2. STAND ESTABLISHMENT “the sins of planting will haunt you all season”Anonymous A thought worth remembering!!

3. 3 Phases of Established n 3. Seedling establishment STAND ESTABLISHMENT 2. Seed germination & emergence • Seed bed • preparation/planting

4. Establishment –Phase I n STAND ESTABLISHMENT • Seed bed • preparation/planting

5. SEEDBED PREPERATION “The facet of stand establishment in which the greatest sins are committed!”

6. SEEDBED PREPERATION • The 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 problems • Reduce yield • Increased production cost

7. 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

8. PLANTING SEED PLACEMENT IMPACTS STAND ESTABLISHEMT • TOO DEEP: • 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 Lateral placement Depth placement Depth: 3 times the seed width

9. OVER SEEDING CAN CAUSE PROBLEMS WITH UNIFORMITY/QUALITY Poor in-row spacing

10. Establishment- Phase II PHASE 2 2. Seed germination & emergence

11. GERMINATION • The process by which a viable(living) seed imbibes water, triggering respiration, protein synthesis and other metabolic activities which cause radicle emergence.

12. GERMINATION Seeds are considered to have germinated once radicle emergence has occurred Germinated seed (Radicles emergenced)

13. GERNIMATION (ENVIRONMENTAL FACTORS) • Moisture • Seed content • Soil content • Temperature • Oxygen/gas exchange

14. SEED MOISTURE CONTENT • Seeds stored 4 - 5 % moisture content • Water needed to active metabolic processes • Excess moisture • inhibits gas exchange(stops metabolic processes) • leakage of sugars, organic and amino acids • increase pathogen susceptibility(substrate)

15. 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

16. 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.

17. GERMINATION(Soil physical properties) • Soil moisture content • Soil temperature • Soil insect and disease pressure • Soil impedance

18. FACTORS IMPACTING GERMINATION & EMERGENCE • Soil temperature

19. TEMPERATURE & GERMINATION • Generally 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 inhibited • temperature impact pathogen activity which can have a detrimental effect on germination

20. INFLUENCE OF SOIL TEMPERATURE ON GERMINATION

21. INFLUENCE OF SOIL TEMPERATURE ON EMERGENCE

22. SOIL TO SEED CONTACT • Onset of germination delayed at soil matrix potentials • Highest germination % between -0.3 & -0.1 • Soil matrix potentials outside of this range – DELAYED GERMINATION

23. 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

24. SOIL FACTORS IMPACTING GERMINATION & EMERGENCE • Soil impedance – the pressure or barrier effect soil has on emergence.

25. 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 force • Crust and/or deep planting very disastrous to crops lacking good emergence force

26. EMERGENCE VIGOR • The ability of a hypocotyls to rapidly emerge through the soil profile and emerge above the soil surface.

27. FACTORS IMPACTING GERMINATION & EMERGENCE • Soil insect and disease pressure

28. Establishment- Phase III Seedling establishment PHASE3

29. 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

30. STAND ESTABLISHMENTGOAL • TO REDUCE THE TIME REQUIRED FOR SEED GERMINATION TO SEEDLING ESTABLISHMENT

31. n 3. Seedling establishment STAND ESTABLISHMENT 2. Seed germination & emergence • Seed bed • preparation/planting

32. 3 COMPONENTS OF STAND ESTABLISHMENT • Good Soil Conditions • Viable Seeds • Favorable Microclimate

33. GOOD SOIL CONDITIONS (COMPOENT # 1)

34. IDEAL SEED BED SOIL CONDITIONS • Well pulverized • Free of clods and plant residue • Firm and level • Provide good soil to seed contact

35. MEANS of ACHIEVING GOOD SOIL to SEED CONTACT • Ovoid working soil when wet • Ovoid excessive disking, causes compaction restricts root growth & yield • Pulverize soil to the point that it is free of clods and debris • Rotovators are ideal implements

36. VIABLE SEEDS (COMPOENT # 2)

37. SEEDS • Embryonic orNew plants • plant in miniature - • Contained in a Dispersing structures • protected in a cover (the seed coat) until a self sufficient autotrophic organism can be established

38. VIABLE SEED • Seed Having The Ability To Germinate and develop into a seedling once planted!

39. FACTORSINFLUENCING SEED VIABILITY • Seed coat (testa) • Food reserves • Dormancy • Condition under which seed produced • Storage conditions

40. SEED COAT CHARACTERISTICS • Surface area • Nature of the surface • Mucilage content • Thickness • Porosity

41. 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

42. SEED FOOD RESERVES • Quantity determined by the quality of the seed crop • Growing conditions • Harvest • Storage

43. CONDITIONS UNDER WHICH SEED CROP IS GROWN • Stressed plants are weak plants which in turn produce unviable or poor germinating seed

44. SEED DORMANCY • The failure of seed to germinate even under apparently favorable conditions • Due to a inherent blocking mechanism within the seed

45. SEED DORMANCY • Causes: • Chilling requirement • Excessive temperature • Inhibitors • Seed coat thickness

46. FAVORABLE ENVIRONMENT (COMPOENT # 3)

47. ROOT ZONE MICROCLIMATE (POST GERMINATION TEMPERATURE & MOIUSTURE STRESS) • Radicle injury or death • Hypocotol injury or death • No, or poor or uneven stands • reduced yield

48. INFLUENCE TEMPERATURE ON EARLY GROWTH

49. INFLUENCE OF MICROCLIMATE ON STAND ESTABLISHMENT Covered Trenches Fruit nearing maturity No fruit Non Covered Std. beds

50. SEEDING RATE • Inadequate rates, poor stands due to lack of potential seedlings emerging • Excessive rates, over crowding weak spindly plants