Regeneration of Natural Pasture in Enclosures for Parthenium Weed Management in the Rangeland of

Jigjiga, Somali Regional State, Ethiopia

BY Lisanework Nigatu, Tamado Tana and

Hassen Ali

14 July 2014Nexus Hotel, Addis Ababa

Outline

1. Introduction 1.1. Objectives2. Study Methods3.Results and Discussions4. Conclusions5. Acknowledgments

1. Introduction

• Parthenium is one of the most troublesome weed:

• Invading extensive natural rangelands and agricultural fields in Eastern part of Ethiopia.

• Threatening biodiversity, natural resources, human and animal health

Pathenium Weed Population

1. Introduction Cont….

Invades Cultivated fields Invading natural rangeland

Area Enclosure as a Management tool to Combat Parthenium invasion:

1.1. Objectives

• Investigate the species composition and diversity of the natural pasture, and

• Evaluate the relationship between the regeneration of natural pasture and the soil seed bank flora.

Fig 1. Map of the study area

2. Study Methods:• The study was conducted in three land use

types:five years enclosures for parthenium management, twenty years enclosures (bench mark) and communal grazing lands.

• Data on herbaceous layer were collected from a total of 45 quadrats, each 1m × 1m, laid out randomly in 9 sample sites, each measuring 10m×10m.

2. Study methods cont..

• The data were collected on the regeneration of herbaceous species and included:– species composition, – Diversity and basal cover, – seedling number and – age categories– Data for soil seed bank flora included seedling

density, species composition and diversity

2.Study Methods cont…

• Soil sample collection for seedbank study

Soil seedbank flora study in a geen house

3. Results and discussion

• The study revealed significant (P<0.05) variation among land use types in grass species composition, basal cover, age category, and herbaceous species richness.

• Relatively higher mean values were recorded for all these parameters in the five year enclosure land use type and intermediate value scored in twenty year enclosure followed by the open grazing land use type.

Table 1. LSM SE of herbaceous (grass) score species composition, species richness, basal cover, age distribution, biomass and seedling number of the land use types.Land use

Type

Species

composition

Basal cover

( m-2)

Age

distribution

(m-2)

Species

richness

Seedling

number/

A4

Biomass (gm-

2)

Five-year

enclosure 6.730.17a 72.33 3.15 a 2.130.19a 6.660.38 a 4.600.13 a

795.449.9 a

Twenty-year

enclosure 5.060.26b 64.535.37b 4.460.13 b 5.460.44 b 4.600. 13 a 395.4028.2b

Open grazing

land 3.730.13c 26.33 1.98 c 1.600.21c 4.660.37 c 4.46 0.13a 121.78.08 c

P in ANOVA 0.00 0.00 0.00 0.00 NS 0.00

abcd Means within a column with different superscript are significantly different at P 0.05 NS= none significan

3. Result & Discussion Cont…

• A total of 39 herbaceous species were recorded in the study sites of which14(35.89%) species were grass and 25(64.10%) non-grass species.

• The study revealed that very few grass species dominated the open grazing land use type whereas a relatively good proportion of the important grass species were represented in both enclosed areas of varying years.

3. Result and Discussion cont…• Grass species such as Chrysopogon aucheri,

Cenchurs ciliaris, Cynodon dactylon, Aristida mutabilis, Digitaria abyssinicum, Digitaria spp. Hyparrhenia hirta and Tragus heptahuron occurred frequently forming the major constituents of the sites.

• The grass species composition had significantly (P<0.05) lower mean score for open grazing land use followed by twenty year enclosure (Table 1).

• Basal cover, age distribution, seedling number and dry matter biomass grass species all scored higher in five year enclosure followed by 25 years enclosure and communal grazing land types . respectively

• Determination of fresh Weight of Herbaceous Biomass in the Sampled Plots

3. Results and Discussion cont….• The soil seed bank study

revealed that a total of 38 species representing 15 families of flowering plants germinated in the green house experiment.

• The forbs comprised 63.15%, grass 31.57% & legumes 5.26%, of the total germinated plant species.

0

5

10

15

20

25

30

35

5.72.8 2.8

34.28

20

2.85.7 5.7

2.8 2.8 2.8 2.8 2.8 2.8 2.8

%of families

Figure 10.seedling families collected from the soil seed bank

3. Results and Discussion cont….

• The most common species in the soil seedbank were Parthenium hysterophorus Eragrostis spp. and Chrisopogon aucheri.

• Parthenium hysterophorus accounted for 44.25% of the total species composition followed by Eragrostis spp. (16.12%) and Chrysopogon aucheri (6.6%).

• This result, confirmed that the soil seed bank of Jigjiga rangeland was dominated by invasive weed Parthenium hysterophorus

Table 2. Mean SE for the species seedling density of layers among the three land use types.

Land use type Layer 1 (0-3 cm) Layer 2 (3-6 cm) Layer 3 (6-

9cm)

Five year

enclosure

16.061.28a 6.53.79a 4.00.55a

Twenty year

enclosure

15.81.99b 5.00.72b 3.93.45 b

open grazing

land

7.80.726c 4.26.67c 2.7.26c

P in ANOVA 0.00 0.00 0.00

abcde Means within a row with different superscript are significantly different at P < 0.05

3. Results and Discussion cont….• There was significant

(P<0.05) difference in seedling density and species composition along land use type and layers

• The highest seedling number of the layers was recorded in five year enclosure, followed twenty years enclosure and least was on the open grazing Seedling density Count from soil seed bank study

Table 3.Seedling density in m-2 (Mean SE) of forbs, Grasses and legumes along soil dept

Layer Forbs Grasses Legumes Grand Total

Layer 1(n=45) 20.13.28a 9.53.89a 0.46 .19a31.121.36 a

Layer 2(n=45) 13.201.58b 7.8.80 b 0.20.10 b 21.202.48 b

Layer 3(n=45) 9.00.81c 5.7.73 c 0.13 .13c 14.831.67c

P in ANOVA 0.000 0.006 0.000

0.000

abcd Means within a column with different superscript are significantly different at P < 0.05

3. Results and Discussion cont….• There was significant variation (P<0.05) in forbs, grasses

and legumes seedling density in the soil seed bank germination between land use types and layers

• The highest herbaceous (forbs, grasses & legumes) seedling density was recorded from the first layer followed by second layer and third layer. Seedling density decreased as the depth of the soil seed bank increased

• Both enclosures showed the highest seedling density of herbaceous species (forbs, grasses & legumes) than the open grazing land use type.

3. Results and Discussion cont….

Similarity between the soil seed bank flora and the standing vegetation:

• There was lower similarity between species composition in soil seed bank flora and standing vegetation (Jaccards similarity index=16%)

• The similarity between species numbers and composition of the soil seed banks and the above ground vegetation was low .

• The low similarity was related too many woody species in above ground vegetation and more abundance of perennial grasses and annual forbs in the soil seed bank.

4. Conclusion

• The present study revealed that the two enclosures land use type in the Jigjiga rangeland have shown relatively higher level of naturally regenerating vegetation cover with declining parthenium weed invasion and soil seed bank flora.

• Therefore, expansions of enclosure with proper grazing management options and reseeding of the enclosures areas with indigenous and compatible pasture species are recommended for improvement of the Jigjiga rangeland.

5. Acknowledgements

• USAID through IPM/CRSP- Virginia State University • Haramaya University

Thank U !!!