1. Seedling emergence of Shepherd's needle (Scandix pecten-veneris)
as affected by year time and burial depth
Souipas Sp.1, Bardavakis Emm.2 and Lolas P.1
1Weed Science Laboratory, 2Laboratory of Agronomy,
Dept. of Agriculture Crop Production and Rural Environment,
University of Thessaly, Volos, Greece

2. Useful tool in weed control Prediction of weed emergence ?
INTRODUCTION:
Weed Biology-Ecology
Seed behavior in soil
Emerging time of seedlings
Useful tool in weed control
Prediction of weed emergence ?

3. Shepherd's needle (Scandix pecten-veneris) (greek name : Μυρώνι)
WHAT IS IT ?
Common broadleaf weed in winter cereals in Greece
Family: Apiaceae
Biol. cycle : winter annual
seedlings
Fruit-seed

4. Young plants
Fruit
Flower

5. Aim of study : Evaluate seedling emergence of Shepherd's needle
as affected by
I. Year time II. Burial depth

6. I. Year time seedling emergence
MATERIALS AND METHODS:
I. Year time seedling emergence
1. Natural field population
2. Population of sowed seeds
Location :
Research Farm of University of Thessaly, central Greece
Year

7. - Measurements : - Plot : 2.5 m2 - Replications : 4
Year time - seedling emergence experiment
1. Natural field population
- Measurements :
Number of seedlings emerged every
10 days
(counted and then removed by hand)
- Plot : 2.5 m2
- Replications : 4
Soil temperature (5cm) recorded by
data logger.

8. Year time - seedling emergence experiment
2. Population of sowed seeds
20 mature seeds were sown every 10 days in a field without natural population.
(spacing 20x100 cm, depth 4cm)
- Measurements :
Number of seedlings emerged, time of emergence
- Replications : 4
Soil temperature (5cm) recorded by
data logger.

9. Burial depth seedling emergence
- Location – time :
Research Farm of University of Thessaly, 2008, central Greece.
20 mature seeds were buried (field without natural population), depths:
and 15 cm
- Measurements :
Number of seedlings emerged
- Replications per depth : 4
Sowing times: 5
14 Feb, 16 Mar, 1 Apr, 18 Apr, 24 Nov
Soil temperature (5cm) recorded by
data logger.

10. RESULTS Emergence of Scandix pecten veneris in a
Year time - seedling emergence experiment
Mean density (plants/m2)
Mean soil temperature at 5cm ( 0C )
Date
Emergence of Scandix pecten veneris in a
natural field population during the year

11. Emergense of Scandix pecten veneris
Year time - seedling emergence experiment
Emergence %
Time of emergence (Days after sowing)
7/11
19/11
29/11
12/12
22/12
6/1
16/1
28/1
7/2
18/2
28/2
11/3
21/3
31/3
10/4
20/4
30/4
10/5
25/5
Sowing date
Emergense of Scandix pecten veneris
as affected by sowing date ( )

12. Emergense of Scandix pecten veneris
Year time - seedling emergence experiment
Emergence (%)
Time of emergence (Days after sowing)
Sowing date
Emergense of Scandix pecten veneris
as affected by sowing date ( )

13. Burial depth - seedling emergence experiment
24 /11/ 2008
Days after sowing 20 27 32 42 62
Depth,cm
Emergence (%)
2.5 19 66 73 86 5 12 69 72 76 91
7.5 - 50 61 75 85 10 36 47 54
12,5 11 21 41 51 15 14 26
Soil temp.
Mean min.
6.7
6.8
6.1
5.2
5.3
Mean max.
12.4
12.5
11.6
10.5
10.7

14. 14 / 2 / 2008 58 28 Burial depth - seedling emergence experiment 20 27
Days after sowing 20 27 32 39 48
Depth,cm
Emergence (%)
2.5 10 80 88 90 5 - 55 70 75
7.5 40 63 35 50 58
12,5 25 28 15
Soil temp.
Mean min.
4,4
5,4
5,7
6.6 7
Mean max.
15,2 16
16,8
17,3

15. 13 / 3 / 2008 79 61 34 Burial depth - seedling emergence experiment 18
Days after sowing 18 23 29 35 41
Depth,cm
Emergence (%)
2.5 50 65 74 75 5 55 78 80
7.5 25 85 88 10 73 79
12,5 3 60 61 15 30 31 34
Soil temp.
Mean min.
9,4
9,3
9,8
10,6
Mean max.
19,7
19,8
20,4
20,7
21,2

16. Burial depth - seedling emergence experiment
1 / 4 / 2008
Days after sowing 14 20 26 38
Depth, cm
Emergence (%)
2.5 10 35 45 46 5 15 56 59 60
7.5 - 54 65 30 48
12,5 40 3 13
Soil temp.
Mean min.
10,4
10,6
11,4 12
Mean max.
21,3
21,5
22,1

17. Burial depth - seedling emergence experiment
18 / 4 / 2008
Days after sowing 20 27 36
Depth, cm
Emergence (%)
2.5 3 5 - 8
7.5 1 10 4
12,5 15
Soil temp.
Mean min.
13,3
13,5
14,4
Mean max.
23,3 23
23,6

18. Pick in emergence occurred in December
CONCLUSIONS:
Natural population started to emerge in the beginning
of October and stopped after 15 April.
Pick in emergence occurred in December
(2760 plants/m2, mean soil temp. 7-10oC )
( plants/m2 from 10 Nov. to 9 Feb. )
Zero emergence between Apr. and Oct.
mean soil temp. over 18oC

19. Seeds sowed 20 Oct. to 1 Dec. and 20 Feb.
emerged faster ( days after sowing)
and in higher percentage (75-92%)
Seeds buried deeper than 12.5 cm :
emergence was low (10-34%).
Soil tillage at 15 cm or more can reduce plant density
of this weed

20. Practical use of results
Prediction system for weed emergence – control strategy by combining seed depth,
soil temperature and knowing optimum temperature
for seed germination

21. Thank you
for your attention