The Effect of Arbuscular Mycorrhizal Fungi Inoculation on the Quality of Seedlings for the National Greening Program in the Philippines

Transcription

1 The Effect of Arbuscular Mycorrhizal Fungi Inoculation on the Quality of Seedlings for the National Greening Program in the Philippines Angela Ferraren, Nestor Gregorio, Lourdes Agne Mayet Avela and Arturo Pasa

2 Biliran, Philippines

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4 Average erosion rate (tons ha -1 yr -1 )by region in the Philippines in Dotted line represents the average erosion rate. (FAO, 1998)

5 The National Greening Program is the Philippine government banner program for massive forest rehabilitation Target: 1.5 B trees in 1.5 M ha of public lands nationwide between 2011 to 2016.

6 Greening the Philippines NGP requirement: rapid production of high quality seedlings The successful establishment of seedlings after outplanting, especially in stressful sites, depends upon good seedling quality

7 Seedling Quality Physico- chemical characteristics of potting media are critical for the success in nursery seedling establishment and consequently in the field Growth and performance of nursery stock are oftentimes related to the nutrient supplying capacity of the potting media.

8 Seedling Quality Improving the fertility of nursery soils is essential to guarantee the production of high quality seedlings. Small scale tree seedling nurseries in the Philippines use the soils collected locally in raising seedlings and most often these soils are deficient in mineral nutrients

9 Seedling Quality Arbuscular mycorrhizal fungi (A MF) inoculation has been proposed and then adapted as a solution in attaining good growth performance of seedlings in the NGP reforestation sites

10 AMF in National Greening Program In 2013:The Department of Environment and Natural Resources (DENR) produced 155 tons of AMF inoculant and distributed them to different regions in the Philippines to ensure the supply of AMF inoculum for planting materials for the NGP

11 Why AMF inoculation? AMF can form mutualistic symbioses with most tropical forest species. AMF inoculation in the nursery may provide better growth, and vigour of seedlings to cope with transplantation stress. AMF population is low because the soils used in the nursery are often collected from barren surroundings and may have been stored for a long time.

12 Research Questions Will AMF inoculation improve the nursery growth performance of A. falcataria using a potting medium of low fertility? Will addition of small amount of chemical fertilizer improve the effectiveness of AMF inoculation in nursery seedlings with less fertile potting medium? Which will have the strongest effect (potting medium, fertilizer or AMF) on the growth, biomass production, photosynthetic rate, nutrient concentration and AMF infection of A. falcataria seedlings in the nursery?

13 Treatments & Experimental design 2x2x2 factorial in Randomized Complete Block Factor A Potting Mix : Soil alone, Soil + Rice Hull Factor B Fertilizer level: Distilled Water, Nutrient Solution - 8 mg N - 6 mg P 6 mg K/seedling Factor C AMF Inoculation: Without AMF, With AMF Replications:3 Test plant: Albizia falcataria

14 Measurements Biweekly seedling height and base diameter from two to 14 weeks after potting Photosynthetic potting, rate: at harvest, four months after Nodulation, biomass and nitrogen, phosphorus and potassium concentration, and AMF infection of harvested seedlings

15 Characteristics of Potting Mix Soil Alone Soil + rice hull ph Total OC (%) Total N (%) Total P (%) Total K (%)

16 Main effects: seedling height from two to 14 weeks after potting Source of variation Empirical Probability Values Potting mix ns ns ns ns ns ns ns Fertilizer ns ns ns ns 0.025* ns 0.053* Inoculation ns ns ns ns ns ns ns

17 Main Effects: seedling base diameter at two to 14 weeks after potting Source of variation Potting mix Empirical Probability Values ns ns ns ns ns ns ns Fertilizer ns ns ns ns 0.010* 0.006* 0.006* Inoculation ns ns ns ns ns ns ns

18 Fertilizer Effect: Height of A. falcataria from two to 14 weeks after potting Unfertilized Fertilized Biweekly Plant height 100 cm Weeks

19 Fertilizer Effect: Base diameter of A. falcataria from two to 14 weeks after potting Unfertilized Fertilized Biweekly Base diameter mm Weeks

20 Main effects: Ps rate, nodule number, nodule dry weight, shoot and root dry weight and root:shoot ratio Source of variation Ps rate Empirical Probability Values Nodule Number Nodule Dry Weight Root Dry Weight Shoot Dry weight Root: shoot ratio Potting mix 0.005** <0.001** 0.000** 0.804ns 0.019* ns Fertilizer ns <0.001** 0.007** 0.024* 0.005** ns Inoculation ns ns ns ns ns ns

21 Main Effects: Shoot and root nutrient concentration, and mycorrhizal infection Source of variation Empirical Probability Values Shoot Root Total N Total P Total K Total N Total P Total K Mycorrhizal infection Potting mix 0.012* <0.001** ns 0.007* <0.001** ns ns Fertilizer ns ns 0.050* ns ns 0.016* <0.001** Inoculation ns ns ns ns ns ns ns

22 Potting Mix Effect: Ps rate, nodule number and dry weight, shoot dry weight Ps rate Nodule Number Dry Matter Yield Potting mix (mg plant -1 ) (g plant -1 ) Nodule Shoot Soil alone 7.90b b 3.78 b 0.57b Soil + rice hull 9.17a a 7.60 a 0.72a

23 Potting mix Effect : Nitrogen and phosphorus concentration in shoot and root Shoot Root Potting mix Total N Total P Total N Total P % % Soil alone 2.19b 0.09b 1.63b 0.65b Soil +rice hull 2.46a 0.12a 1.84a 0.93a

24 Fertilizer Effect: nodule number and dry weight, root dry weight and shoot dry weight Fertilizer level Nodule Number Dry Matter Yield (mg plant -1 ) (g plant -1 ) Nodule Root Shoot Unfertilized b 4.83 b 0.38 b 0.57b Fertilized a 6.56 a 0.76 a 0.72a

25 Fertilizer Effect : Shoot and root K concentration and mycorrhizal infection Total K Mycorrhizal Fertilizer level Shoot Root % infection Unfertilized 0.79b 0.43b 27.41b Fertilized 0.84a 0.48a a

26 AMF Inoculation X Potting Mix Interaction effect: Ps rate Without AMF With AMF umol-2s Soil alone Soil + ricehull

27 Fertilizer X Potting Mix Interaction effect: Nodule number Soil alone Soil + ricehull No. of nodules Unfertilized Fertilized

28 Conclusion and Implications Potting mix of soil with organic amendment and application of small amount of chemical fertilizer enhance growth, nodulation, biomass production and shoot and root N, P and K of A. falcataria seedlings. The absence of positive influence of AMF on the growth performance of unfertilized A.falcataria seedlings grown in soil alone implies that AMF inoculation alone for growing seedlings in potting medium with low fertility should proceed with caution.

29 Conclusion and Implications Blanket recommendation of AMF inoculation of seedlings in the nursery for the NGP in lieu of fertilizer applications needs to be revisited. Is the fertility of the potting medium more limiting? Does the potting medium contain native AMF?

30 The forests of tomorrow depend on the seedlings of today