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

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 ?

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

Young plants Fruit Flower

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

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 2008-2009

- 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.

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.

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: 2.5 5 7.5 10 12.5 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.

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

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 (2007-08)

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 (2008-09)

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 / 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

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

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

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

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 ) (139-299 plants/m2 from 10 Nov. to 9 Feb. ) Zero emergence between Apr. and Oct. mean soil temp. over 18oC

Seeds sowed 20 Oct. to 1 Dec. and 20 Feb. emerged faster (17- 22 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

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

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