Session 5.4 arbuscular mycorrhizal assoc and growth response of faidherbia

Arbuscular mycorrhizal association and growth response of Faidherbida albida (Del.) A. Chev. as influenced by land use type, in the Northern Ethiopia

By: Mengsteab Hailemariam

February 2014

1. Introduction1. Introduction

1.1. Background and justification

Faidherbida albida:Leguminous agroforestry tree, used in arid and semiarid zones of Africa for soil conservation and soil fertility improvements.

Establishment and growth in dryland areas is very slow due to hostile environmental conditions.

plants possess against stress, grow in association with number of soil micro-organisms that can alleviate the stress symptoms.

AM are common underground symbiosis in revegetation by contributing to nutrient cycling processes

Cont’d…

before considering inoculation, a site's native inoculum potential should be evaluated Relationship between propagule abundance and plant

growth response is almost certainly not linear.

important to include plant response to different soil inoculum sources.

Cont’d…

The objectives of the study were: To determine spore abundance of AM in the soils

of F. albida trees grown in different LUs;

To estimate the extent of AM colonization of root of F. albida trees grown in different LUs, and

To investigate the effect of inoculation on the growth performance of F. albida seedlings;

2. Materials and methods2. Materials and methods

GH experiment was conducted in MU (130 290 N and 390 28 E altitude 2200 m.a.s.l.)

F. albida trees grown on different Lus, same agro-climatic condition and season were selected.

samples were collected for Spore analysisSpore analysis, AM colonization, , AM colonization, physico-chemical physico-chemical

analysisanalysis and and green house experimentgreen house experiment. .

Cont’d…

Soil properties OM, Total N, Ava. P, Exchangeable bases (Na, K, Ca

and Mg), and CEC, BD, pH and EC, and Soil texture

Spores: Extracted from 100g of air-dried sub-samples by wet

sieving and decanting method followed by flotation-centrifugation in 50% sucrose (Brundrret et al., 1996).

identified to genius level (Brundrett et al., 1996, and INVAM)

Cont’d…

AM colonization %estimated by the gridline intersect method

(Giovannetti and Mosse, 1980).

AM fungal inoculum preparation propagated on Sorghum bicolor plants 50 gm of fungal inoculums was added to each

experimental seedlings. controls were prepared without AM fungal propagules

Cont’d…

Seed treatment, planting and growing conditionsSeed treatment, planting and growing conditions

Seeds collected were surface sterilized and allowed to germinate on petridish and sown

Potted seedlings watered to field capacity.

Four treatments, arranged in CRD of five replication

Plants harvested after 12 weeks of growth and growth parameters were determined.

Cont’d…

Statistical analysisStatistical analysis

Data were subjected to ANOVA using SAS statistical software (SAS, version 9).

Relationship were evaluated by employing Pearson’s correlation coefficient.

Result and discussionResult and discussion

Soil properties and vegetation characteristicsSoil properties and vegetation characteristics

Significant difference in N, P, K, OC, Ca, Mg, Na, CEC and textural classes (P<0.05) showed in the three LUs.

Cul. and gra. Lands: weeds and variety of grasses, but area exlo. : grasses, herbaceous plants, shrubs species.

Significant (P<0.05) difference in DBH and Height of trees observed

Table 1: Mean plot characteristics of each LUT (Mean ± S.E of three replicates).

 Soil properties

Unit  

Land use type    Cultivated land Grazing land

Area exclosure F P

pH (H2O, 1:2.5) 6.90 ± 0.09 6.71 ± 0.29 6.97a± 0.17 0.16 0.8522EC (ds/m) 0.15 ± 0.03 0.18 ± 0.05 0.11 ± 0.03 1.12 0.3857O.C (%) 1.003a ± 0.019 1.028 a± 0.061 0.8 b± 0.049 7.16 0.0257N (%) 0.074a ± 0.002 0.062a ± 0.06 0.035b ± 0.005 19.68 0.0023

Av.P (ppm) 13.07a ± 0.91 10.17 a± 1.46 1.46b ± 0.4925.68 0.0011

K (centmol(+)/kg 1.078a ± 0.057 0.778b ± 0.075 0.221c ± 0.03455.68 0.0001

Ca (centmol(+)/kg 2.67a ± 0.291 2.6 a± 0.208 1.4b ± 0.116 10.8 0.0103

Mg (centmol(+)/kg 2.58a ± 0.265 1.78b ± 0.104 1.18c ± 0.25710.09 0.0121

Na (centmol(+)/kg 0.507a ± 0.023 0.362ba ± 0.029 0.217b ± 0.00245.96 0.0002

CEC meq/100gm 6.20ba ± 0.378 7.733a ±0.698 4.80b ± 0.378 8.33 0.0185BD (g/cm3) 1.616 ± 0.039 1.471 ± 0.039 1.529 ± 0.037 3.64 0.0924

sand % 68.33b ± 0.67 86.33a ± 2.91 91.00a ± 1.1642.04 0.0003

silt % 19.00a ± 1.16 5.67b ± 1.76 3.0b ± 1.5538.15 0.0004

clay % 12.67a ± 0.67 8.0b ± 1.15 6.0b± 0.019.75 0.0023

Tex. Class   Sandy loam Sandy Sandy    DBH cm 49.4a±2.5 48.8a±6 16.4b±1.2 23.88 0.0014Height m 9.7a±0.9 7.9ba±0.4 6b±0.8 5.92 0.0381Crown diameter m 11.7b±0.7 14.6a±1.2 7.6c±0.5 15.75 0.0041

AM spore abundanceAM spore abundance

significant differences (F=24.01, P<0.0014) observed among samples collected from three LUs.

highest spores on soil samples from area exclo. and lowest from gra. land.

four genera recorded in all LUs. Glomus: abundant and frequent genus in all LUs

followed by Gigaspora Scutellospora and Acaulospora

AM root colonizationAM root colonization

Significant (F= 11.62, P= 0.0086) variation observed among tree root grown on different LUTs (Table 2).

Table 2: Spore abundance (100 gm-1 of dry soil) and AM root colonization of F. albida trees grown on different LUs. Mean ± S.E of three replications.

Land use type Spore abundance

F P AM root colonization

F P

Area exclosure 3041.3a ±148.34

24.01

0.0014 71.1a±1.7 11.62 0.0086

Grazing land 1364.0c ±205.56

66.5a±1.4

Cultivated land 2002.7b ±159.02

61.5b±1.1Means in the same column followed by same letter do not differ significantly at P<0.05

Growth parametersGrowth parameters Inoculated seedlings were colonized by AM fungal

structures (A, V, H) (Table 3).

None from control group were colonized.

the greater growth attained by the plants which were colonized by AM fungi.

significant (P<0.05) growth enhancements of seedlings inoculated with AMF was recorded.

AM colonization was not significantly correlated (r = 0.317, P = 0.376) with spores abundance.

Means in the same row followed by same letter do not differ significantly at P<0.05

Table 3: growth parameters of F. albida seedlings inoculated with AM fungal inoculums collected from the rhizosphere soils of F. albida trees grown on different LUs and AM un- inoculated seedlings. Mean ± S.E of five replicationsGrowth Parameters Unit Soils collected land use type

(AM-) Control

(AM+) Area exclosure

(AM+) Grazing land

(AM+) Cultivated land F value

P value

Height cm 44.0b ±4.16 96.67a±8.09 99.0a±8.96 67.0ba±6.56 13.32 0.0018

Shoot dry mass gm 2.06c±0.17 8.51a±0.39 8.21a±0.32 5.32b±0.49 67.57 <.0001

Root dry mass gm 1.09c±0.13 5.31a±0.79 5.19ba±0.48 2.73b±0.22 18.24 0.0006

Root: Shoot gg-1 0.529a±0.008 0.618a±0.063 0.629a±0.034 0.516a±0.008 2.64 0.1211

Root length cm 607.8d±100.5 3149.1a±189.9 2416.3b±309.8 1605.3c± 204.1 25.93 0.0001

Leaf number num 244.3c±20.4 725a±59.5 715.7a±59.29 609b±66.46 17.12 0.0007

Branch number num 2.33b± 0.88 5.00ba± 1.73 9.00a± 2.31 8.00ba±1.53 3.19 0.0840

AM

colonization % 0.0c±0.0 32.89a±1.60 30.25ba±2.14 25.23b±2.37 71.11 <.0001

Conclusion and recommendationConclusion and recommendation AM association can be influenced by LU systems, age of

trees, and environmental conditions

higher number of spores with low AM colonization observed in cultivated land compared with grazing lands, implies low level of infective AM populations.

Significant growth enhancement was recorded on AM inoculated seedlings.

Cont’d… higher growth performance observed on area exclo and

gra. Land soils emphasis the importance of prior native soil mycorrhizal

potentials for better plant growth improvement and environment protection.

investigating the potential of AM on growth performance of this tree spp. associated with different water levels and fertilizer application is needed, and

field experiment is needed to confirm the inoculation effects of these AM inocula, and