Category Archives: Volume 33 No. 2 (2011)

Heavy Metals Content of Two Red Soils in Samar, Philippines

Author(s): Ian A. Navarrete1,2 and Victor B. Asio2


The study evaluated the total and available heavy metal (Cd, Cu, Cr, Pb, Ni, and Zn) contents of two red soils in Samar, Philippines, one developed from slate near a mining site (Bagacay soil) and the other from serpentinite (Salcedo soil), a well-known source of heavy metals. Soil samples were collected from every horizon in each profile and samples were digested using aqua regia and NH4NO3 to determine total and available heavy metals content, respectively. Results revealed that Salcedo soil had high contents of total Cr (average: 1353 mg kg-1), total Ni (average: 610 mg kg-1), and available Cr (average: 0.19 mg kg-1) that exceeded the maximum allowable contents in agricultural soils but it had low amounts of the available form of the heavy metals. Bagacay soil showed very low contents of both total and available heavy metals due to their low amounts in the parent rock. The red Bagacay soil showed no effect of the nearby mining activity.

Keywords : heavy metals, soil pollution, red soils, Samar island, mining, serpentinite

Annals of Tropical Research 33(2):162-173(2011)

Significant Changes Experienced by Adopters of Sustainable Organic Agriculture Technologies in Ormoc City, Philippines

Author(s): Catherine L. Corcino1 and Editha G. Cagasan2


In an effort to help preserve the environment, several organizations have been promoting the use of sustainable organic agriculture (SOA) technologies. Many farmers have already tried adopting one or a combination of these technologies. This study was conducted in Ormoc City, Leyte, Philippines to determine the changes experienced by farmers after adopting the SOA technologies introduced to them by the Rural Development Institute in Leyte, Philippines (RDI-Leyte). Data were gathered through in-depth interviews with 30 farmer-adopters in seven villages of the city. To determine significant changes experienced by the farmer-adopters, significant change stories were collected and reviewed following the procedures of the Most Significant Change (MSC) technique outlined by Davies and Dart (2005).
Analysis of the MSC stories revealed that there were three kinds of changes experienced by the technology adopters. These include improved knowledge and skills on organic farming systems, improved food quality, and improved economic conditions. These changes correspond to the objectives of RDI-Leyte in their advocacy on SOA technologies and to higher levels (i.e., levels 5 to 7) in Bennett’s hierarchy of program outcomes. This suggests that the efforts of RDI-Leyte to promote SOA technologies have already made some impacts on the technology adopters’ lives.

Keywords : technology adoption, information dissemination, program impacts, Leyte

Annals of Tropical Research 33(2):143-161(2011)

Growth and Yield Performance of Selected Lowland Rice Varieties under Alternate Wet and Dry Water Management

Author(s): Melanie D. Ratilla and Ulysses A. Cagasan


Severe water shortage in many parts of the world has caused enormous yield losses in rice. To continue feeding the increasing number of people who are dependent on rice as staple food, there is a need to address the problem on water shortage. One possible solution may be the application of alternate wet and dry (AWD) water management in rice production.
This experiment was conducted to evaluate the growth and yield performance, as well as the profitability of selected lowland rice varieties under AWD water management. An experimental area of 450m2 with Umingan clay loam soil was laid out in randomized complete block design (RCBD) with three replications. Each replication was subdivided into six treatment plots with an area of 20m2 (5m x 4m) each. The treatments were: T1 – Masipag 45 (M45), T2 – Matatag 6 (M6), T3 – Masipag 129-2 (M129-2), T4 – Pinili-1, T5 -SL-8H and T6 – PSBRc-18 (check variety). Results showed that number of days from planting to heading and maturity, fresh straw yield (t ha-1), number of productive tillers per hill, number of filled grains per panicle and grain yield (t ha-1) differed significantly among treatments (p<0.05). Pinili-1 headed and matured the earliest and produced the highest fresh straw yield (t ha-1). However, M-129-2 and Matatag 6 had the highest number of productive tillers per hill, number of filled grains per panicle and total grain yield (t ha-1) which surpassed that of PSBRc18 (check variety). Masipag129-2 and Matatag 6 also gave the highest net profit of Php 23,805.00 per hectare.

Keywords : lowland rice production, genetic variability, water management practices, cost and return analysis

Annals of Tropical Research 33(2):130-142(2011)

Growth and Survival of Mangrove Seedlings under Different Levels of Salinity and Drought Stress

Author(s): Nit Lyn B. Estomata and Pamela P. Abit


Water availability and salinity are determinants of growth, survival and establishment of mangrove species. This study aimed to compare the ability of the mangrove species to survive extreme water stress, and to determine differences in growth performance and biomass allocation between mangrove species grown in different water levels and saline conditions. Seedlings of Lumnitzera racemosa, Rhizophora apiculata, R. mucronata and Avicennia marina were used. A dry-down experiment was done to compare the ability of mangrove species from different zonations to survive drought stress by evaluating survival rates after re-watering consequent to drought exposure. The different mangrove species were grown at different water levels (dry, well-watered, flooded) and different salinity levels such as low (3-5 ppt), high (25-27 ppt) and pure seawater (32 ppt) to evaluate the growth performance and biomass allocation of the mangrove seedlings.
L. racemosa was the most drought tolerant, followed by R. mucronata and A. marina while R. apiculata was the most drought sensitive. There is a possibility that A. marina may displace the current distribution of R. apiculata in the middle zone while the distribution of L. racemosa and R. mucronata in the landward and middle zone, respectively could be retained. The number of leaves of A. marina was significantly higher than R. apiculata and R. mucronata but was only comparable to that of L. racemosa across all salinity levels. L. racemosa was only significantly different from the two Rhizophora spp. under pure saline treatment. Root length of A. marina was significantly higher than R. apiculata but statistically similar to R. mucronata and L. racemosa. The capacity for root growth may allow roots to exploit water from dry soils and could correspond to the drought tolerance of A. marina, R. mucronata and L. racemosa. There was no significant effect of water and salinity stresses on the biomass allocation.

Keywords : drought stress, water potential, salinity, survival

Annals of Tropical Research 33(2):107-129(2011)

“Rainforestation Farming” – an Appropriate and Applied Ecological Approach for Landscape Rehabilitation and Impact Mitigation of Climate Change in the Humid Tropics

Author: Friedhelm Göltenboth1


While the last century was mainly focusing on conservation measures in landscape ecology, the present century has certainly to deal with restoration, rehabilitation and reclamation of entire landscapes.
Aspects and forms of degradation are discussed in this paper showing the complexity of the task ahead for researchers and applied agriculturists.
The tropical forested areas are of special concern under the aspect of their enormous variety of biotopes and biocoenosis and their protective functions and ecological services to man in a given landscape.
The specific responsibility of agro-forestry systems is described and the innovative “Rainforestation Farming” technology for rehabilitation of degraded landscapes in a “near-to-nature” farming system is described.
The gradual transformation of monocultures into highly diverse tree farming systems is discussed and also some aspects of global dimension, like the reduction of carbon dioxide and aspects of carbon sequestration.

Keywords : Rainforestation Farming, applied tropical ecology, landscape rehabilitation, humid tropics

Annals of Tropical Research 33(2):85-106(2011)

Fish Corral Composition, Abundance, and Distribution in the Reef Flat of Palompon, Leyte, Philippines

Author(s): Jerome Benedict P. Cabansag1, Arriane Krisna Rose T. Tuazon1 and Liezel C. Paraboles2


There is paucity of studies relating to fish corral fishery and its management particularly those operated on reef flats. This study was conducted to evaluate the fish catch composition of fish corrals situated in the reef flat of Palompon, Leyte from July 2009 to January 2010. During the monitoring, two sets of data were utilized: the semimonthly field intercept samplings and the daily fish landing data. Field intercept samplings enabled the researchers to approach fishers as they were gathering their fish catch that was eventually identified, sorted, measured, and weighed. Fish landing data recorded by local enumerators included the fish’s local name and corresponding weight. From 27 fish corrals, the intercept samplings yielded a total catch of 23.9 kg, which was composed of 81 identified species under 47 genera from 31 families. The most abundant family was Siganidae comprising 44% of the total catch, followed by Apogonidae (18%) and Pomacentridae (9%). This composition was corroborated by the fish landed data. The temporal and spatial trends of the catch composition showed that Fam. Siganidae was most abundant in the months of July, October, and December, while Apogonidae in the months of August and November. It was observed that there was an unequal spatial distribution of fish species in the study area. Of the four sampling areas, Area 2 on the northeastern part of Palompon was the most diverse due partly to the high number of fish corral units and the area’s structural complexity wherein seagrass and algal beds were most extensive interspersed with coral patches. Results of this study could serve as reference for future studies dealing with monitoring and managing fish corral fishery.

Keywords : Reef flat, fish corral, spatial distribution, temporal distribution

Annals of Tropical Research 33(2):62-84(2011)

Energy Accounting of Irrigated Wheat Production to Post Production (Baking Bread) in Doroodzan, Fars Province, Iran

Author(s): Seied Mohsen Taghay and Teodoro C. Mendoza


the total energy input (tEI) of irrigated wheat in Fars province, Iran, was estimated at 901 liter diesel oil equivalent per hectare (LDOE ha-1) (423 LDOE or 4819 Mcal, (47%) and 478.14 LDOE or 5454 Mcal, (53%) for wheat production and post production, respectively. the tEI for 1 ton wheat was estimated at 200 LDOE and for 1 ton of bread at 181 LDOE (wheat bread at 28% moisture). the direct use of fossil fuel oil in land preparation, planting, harvesting and transportation was estimated at 106 LDOE ha-1. the applications of fertilizer and pesticide contributed about 40% of the total energy bill in production while it was larger in baking the bread at 72.3 LDOE ton-1 or 75% of the energy costs of post production. At 4515 kg ha-1 average yield of irrigated wheat in Fars province, Iran, the energy output was estimated at 15848 Mcal for raw wheat, 13409.55 Mcal for bread and 2895 Mcal for straw. the energy balance for raw wheat production (field level) was estimated at 3.3. Post- production (baking bread) consumed a lot of energy. the estimated energy balance was 1.3. Measures on how to reduce the energy bill for wheat production and for post-production (baking bread) are discussed.

Keywords : energy balance, energy input, energy output, liter diesel oil equivalent (LDOE), national average yield, organic farming

Annals of Tropical Research 33(2):44-61(2011)

Bioassay-guided Identification of the Nematicidal Secondary Metabolites from Paecilomyces lilicanus for the Control of Root-knot Nematode (Meloidogyne graminicola, Golden and Birchfield)

Author(s): Ruben M. Gapasin1, Erlinda A. Vasquez2 and Giselle A. Rendon3


Meloidogyne graminicola larvae immersed for 48 hours in 100% concentration of Paecilomyces lilacinus culture filtrate had 100% larval mortality while only 7.12% and 18.72% mortality was recorded, after 6 and 12 hours immersion, respectively. Toxic metabolites present in the culture filtrate affected the larvae as there were no galls produced in rice seedlings at 100% concentration. The culture filtrate also limited egg hatching as shown by lesser galls produced in rice seedling roots. The mycelial extract was found more potent compared with the culture filtrate extract; however, both fractions affected the larvae and eggs of M. graminicola.
The dried ethyl acetate fraction gave 88.51% mortality at concentration of 500 mg/ml, followed by 76.91% at concentration of 400 mg/ml. A lethal concentration (LC) of 50% was attained at 300 mg/ml. Sixteen fractions were recovered from the crude dried extract of the fungus using vacuum liquid chromatography (VLC). Bioassay revealed that fraction 3 (combined fractions 5, 6 and 7) gave 39 percent nematode mortality suggesting that the nematoxic compounds are present in these fractions.
The fragmentation pattern in GC-MS revealed that the active fraction contains more than 20 compounds with 5 major ones. The structure of the main compound was partially identified as derivative of azulene containing two unsaturation points. The limited amount of the fraction subjected to spectroscopic analysis does not warrant its purification to be able to do other analysis such as NMR spectroscopy for structure elucidation and complete compound identification.

Keywords : nematicidal, metabolites, nematophagous, Paecilomyces lilacinus, rootknot nematode, Meloidogyne graminicola, culture filtrate, azulene

Annals of Tropical Research 33(2):22-43(2011)

The Status of Floristic Analysis of Mt. Pangasugan, Leyte, Philippines – a Conservation Priority Area Classified as “Extremely High Critical”

Author(s): Gerhard Langenberger1 and Beatriz S. Belonias2


the island of Leyte in the Eastern Visayas takes a central position between the Philippine main islands of Luzon and Mindanao. It is characterized by the Leyte cordillera, which is part of the Philippine fault line. Within the Leyte cordillera, Mt. Pangasugan takes an exceptional role since it provides a catena from lowland forest remnants on its foothills to mossy forest on its summit at 1158 m a.s.l.. recently, Mt. Pangasugan has been identified as conservation priority area classified as of ‘extremely high critical’ level.
Mt. Pangasugan has been the focus of comprehensive botanical studies within the last few years. We present the current status of the floristic assessment of the mountain and introduce the Visayas state University Herbarium, located at the foot of Mt. Pangasugan, where the majority of collected specimens are deposited. At present, the Herbarium houses c. 6100 specimens, 3000 of them originating from the primary forest of Mt. Pangasugan. based on the present status of specimen processing and identification they represent 115 families, and 418 genera of Angiosperms, 2 families, 2 genera, and 3 species of Gymnosperms, 27 families and 64 genera of Pteridophytes, and 3 classes, 38 genera and 51 species of bryophytes. the number of vascular plant species represented in the VsU Herbarium can safely be estimated at c. 800-1000. Given the small overall sampling area intensively studied so far these figures can be assumed as representing just a fraction of the total floristic richness of the area.

Keywords : bryophytes, spermatophytes, pteridophytes, Leyte cordillera, plant collections, vascular plant species

Annals of Tropical Research 33(2):1-21(2011)