Monthly Archives: May 2019

Response of Yakal-yamban (Shorea falciferoides Foxw.), an endangered dipterocap tree species to nutrient addition in a problematic soil

Author(s): Johannes Reiner G. Asio1* and Marlito Jose M. Bande1


The successful establishment of dipterocarp tree species especially in problematic lands is a challenge since it is still poorly understood. The study was conducted to evaluate the effects of the addition of N, P, and K to Yakal-yamban (Shorea falciferoides Foxw.), a critically endangered dipterocarp tree species, grown in a soil derived from an ophiolitic rock. The seedlings were grown in pots inside a screenhouse and then subjected to the following treatments: control, NPK, NP, PK, and NK. Results revealed that NPK addition generally enhanced the growth of Yakal-yamban in the problematic soil, six (6) months after transplanting, particularly in terms of leaf area, biomass increment and allocation in the leaves. The allocation was enhanced in treatments that receive P, in addition to N, NK, or K suggesting that P was the most limiting nutrient in the problematic soil used. The study also revealed the occurrence of ectomycorrhiza in Yakal-yamban where P was not applied. The results imply that NPK addition is a potential nutrient management strategy for the seedling establishment of Yakal-yamban in problematic soils.

Keywords : Dipterocarp trees, Yakal-yamban, fertilization, problem soil, ophiolite

Annals of Tropical Research 41(1):92-101(2019)

Isolation and identification of bacteriocin-producing lactic acid bacteria from plants in Mount Makiling Forest Reserve, Philippines

Author(s): Emil C. Lat1, Francisco B. Elegado1* and Ida F. Dalmacio2


Sixty-three lactic acid bacteria (LAB) were isolated from trapped or stagnated water in parts of 14 different plant species in Mount Makiling Forest Reserve, Philippines and were screened for bacteriocin production. Thirteen of these isolates were found antagonistic to different indicator bacterial strains through direct assay. However, after screening of the pH neutralized culture supernatant using ‘spot-on-lawn’ method against Enterococcus faecium 79 as the indicator strain, only one isolate, designated as ML 258, was confirmed to be bacteriocin-producer. Its crude extract of bacteriocin exhibited inhibitory activity against E. faecium and Lactobacillus aciclophilus. The isolate was characterized and found to be gram-positive short rods that occurred in pairs, singly or in chains, catalase negative, microaerophilic, non-motile, non-spore forming and exhibited a heterofermentative type of fermentation. This isolate was obtained from fern (Microsorum longissimus) and was identified as Carnobacterium piscicola using API 50 CHL kit with good identification of 98%. However, the 16S rRNA gene sequencing and homology search from NCBI database using the BLAST program showed that the isolate is 93-95% similar with Carnobacterium maltaromaticum. On the other hand, phylogenetic analysis using MEGA 5 software that constructed a neighbor joining tree thru bootstrap method revealed that this isolate showed more similarity with Enterococcus sp.

Keywords : Lactic acid bacteria, bacteriocin, Carnobacterium piscicola, Carnobacterium maltaromaticum, Mount Makiling, 16S rRNA

Annals of Tropical Research 41(1):1-15(2019)

Influence of environmental disturbances on the bacteriological quality of Pagbanganan river in Baybay City, Leyte, Philippines

Author(s): Jayzon G. Bitacura


Microorganisms like bacteria are frequently used as indicators of water quality in freshwater ecosystems. Thus, this study was conducted to evaluate the total coliforms (TC) and total aerobic heterotrophic bacteria (TAHB) present in the upstream (Kantagnos), midstream (lgang), and downstream (Kan-ipa) of Pagbanganan River. The most probable number (MPN/100 mL) of TC was determined through multiple tube fermentation test while counts of TAHB present in both water and sediments were enumerated by serial dilution and plating methods. MPN of TC revealed that the river water should not be used as a source of public water supply and as a venue for contact recreational activities like bathing and swimming. Furthermore, TAHB in the sediments of the river did not differ significantly across sites although their values showed a decreasing trend. Conversely, TAHB in the water column of the river significantly increased from upstream to downstream. These results are most probably influenced by the quarrying activities present in the area. In the upstream where there is no quarrying
activity, TAHB was higher in sediment than in the water, while in the downstream where quarrying activities are present, it is otherwise. Because of these significant differences, it is believed that the ratios of TAHB present in the water column and sediments are potential indicators of sediment disturbance in the aquatic environment. The results of this study imply that proper management of Pagbanganan River by all sectors of the community is needed to keep it sustainable for safe use.

Keywords : indicator bacteria, water quality, freshwater ecosystem, anthropogenic impact

Annals of Tropical Research 41(1):81-91(2019)

Response of lowland rice (Oryza sativa L.) to fertilization when grown as main and ratoon crop

Author(s): Dionesio M. Bañoc and Victor B. Asio


Ratooning is widely considered as a strategy to increase lowland rice productivity. However, limited studies have yet been conducted in the Philippines that focus on the fine tuning of this technology. Thus, this study was conducted to evaluate the growth and yield response of main and ratoon crop of lowland rice (PSB R082) to fertilization and to assess the profitability of lowland rice production when grown as main and ratoon crop as influenced by fertilization. Both main and ratoon crop were subjected to the following treatments: T0-No fertilizer application (Control), T1– 90-60-60kgha-1 N, P2O5 and K2O (Inorganic Fertilizer), T2– 10tha-1 Organic Fertilizer, T3– 5tha-1 Organic Fertilizer + 45-30-30 kgha-1 N, P2O2 and K2O. Results revealed that application of inorganic fertilizers at the rates of 90-60-60 and 45-30-30kgha-1 N, P2O5, K2O for the main and ratoon crops, respectively, significantly increased the leaf area index (LAI), number of productive tillers, weight of panicle, number of filled grains and grain yield. The combined application of organic and inorganic fertilizers produced taller plants, heavier straw yield, abundant number of productive tillers, heavy panicle and more filled grains. Plants applied with inorganic fertilizer at the rate of 90-60-60kgha-11 N, P2O3, K2O for the main crop and 45-30-30kgha-1 of N, P2O5, K3O for the ratoon crop resulted in the highest net income.

Keywords : Lowland rice, Fertilization, Ratooning

Annals of Tropical Research 41(1):63-80(2019)

Folk Beliefs and Practices of Bagong (Amorphophallus sp.) Farmers in San Roque, Northern Samar

Author(s): Rhodora Abalajen-Bande and Michael Carlo C. Villas


This study investigated the folk beliefs and practices of bagong farmers of San Roque, a coastal town 29 kilometers from Catarman, the capital town of Northern Samar. Going by Spanish sources, initial readings suggest that bagong, a root crop of genus Amorphophallus, has long been cultivated in Samar (Alcina 1668/2005). Unlike in other parts of the country where the plant is primarily utilized for pig feeding, the bagong in San Roque is served during special occasions like Christmas and New Year. These occasions are preceded by folk practices unique to the community. This study documents bagong farming and analyzes folk practices, with their attendant narratives and beliefs. Ethnographic observations and interviews were conducted among farmers and townsfolk. Results of the study will have implications on cultural education and cultural policy formulation.

Keywords : Amorphophallus, Bagong production, Folk Beliefs and Practices, San Roque, Samar

Annals of Tropical Research 41(1):45-62(2019)

Indications of enhanced soil ecosystem functions in polyculture reforested grassland

Author(s): Angelica P. Baldos1* and Roland Rallos2


A lot of work has been doneto evaluate the effects of biodiversity on ecological functions in polyculture plantings. But attention is rarely given to soil ecosystem functions such as carbon (C) sequestration and nitrogen (N) cycling even though they play a critical role in climate regulation through the sequestration and release of greenhouse gases (GHGs). In this study, stable isotopes of C and N were used to investigate if the aforementioned soil ecosystem functions are enhanced under polyculture reforestation by determining the sources of C stored in soil, its rate of incorporation, and the degree of soil N cycling. Twenty-five years after its establishment on an Imperata cylindrica grassland, the tree plantation has contributed 54% of the measured soil organic carbon (SOC) stock at an estimated rate of 2.41Mg C ha-1 yr-1. Larger mean soil 15N values and a more negative 15N enrichment factor (ε = -5.82‰) for the whole 50cm soil depth in tree plantation indicated a better N cycling compared to grassland vegetation. Results show the potential of polyculture reforestation as a sustainable approach to restoring degraded lands and enhancing the role of soil in climate regulation by improving the capacity of soil to store C and to supply N. In addition, information generated from studies like this allow the refinement of mechanisms used in payments for ecosystem services to add more value and provide higher incentives from the ecosystem services provided by polyculture reforestation.

Keywords : stable isotopes, polyculture reforestation, payments for ecosystem services, SOC sequestration, soil nitrogen cycling

Annals of Tropical Research 41(1):32-44(2019)

Extrapolating the bypass potential of treated Madre de agua (Trichanthera gigantea Nees) leaf meal as protein source in Rumen-Fistulated Brahman Cattle

Author(s): Angelo Francis F. Atole1 and Lolito C. Bestil*


This study assessed the effectiveness of formaldehyde, heat, and tannic acid treatments of madre de agua leaf meal (MALM) in reducing the degradation of dry matter (DMD) and crude protein (CPD) in the rumen for increased supply of bypass protein at the intestinal level. The experiment utilized a rumen-fistulated Brahman bull fed with chopped Napier grass soilage (basal diet) and MALM (test diet) at 70:30 basal:test diet ratio. Nylon bags (porosity of ±53μm) containing the treated MALM were incubated in the rumen for 24, 48 and 72 hours following the “sequential addition” method forin situ degradation measurement.
Results showed that DMD of MALM was significantly reduced by formaldehyde treatment after 24-h and 48-h period of incubation than the untreated. This was followed by tannic acid treatment, though the reduction was significant only after 48-h incubation than the untreated. At 72-h period of incubation, DMD remained to be significantly lowest with formaldehyde treatment than the untreated or heat and tannic acid treatments. A similar pattern of differences in DMD rate (%/h) was observed as that of DMD (%). The CPD of MALM was also significantly reduced with formaldehyde treatment after 24-h incubation than the untreated. At 48-h incubation, all treatment methods showed significant protection of protein in MALM over that of the untreated. At 72h, formaldehyde and heat treatments significantly reduced the CPD of MALM compared to the untreated. A similar pattern of differences in CPD rate (%/h) was observed as that of CPD (%). Among treatment methods, the use of formaldehyde is the best, followed by tannic acid treatment, in achieving rumen bypass and promoting greater amino acid supply at the intestinal level.

Keywords : bypass protein, in situ degradation, cattle, formaldehyde, heat, tannic acid

Annals of Tropical Research 41(1):24-31(2019)

In vitro molluscicidal activity of wormwood (Artemisia dubia) leaves against Oncomelania hupensis quadrasi

Author(s): Charles Jardian C. Alinsub and Melvin A. Bagot*


There have been many efforts to eradicate the problem of schistosomiasis. One method is to control the growing snail population. This study aimed to determine the molluscicidal activity of wormwood (Artemisia dubia)leaves methanolic extract against adult and juvenile. Using infusion technique, 80% methanol was used as solvent. There were eight treatments used: distilled water (T0(-)1) and 1% methanol (T0(-)2) as negative controls; 0.0002% (2mg/L) niclosamide (T0(+)) as positive control; and 11.121% (T1), 12.478% (T2), 14% (T3), 15.708% (T4) and 17.625% (T5), which were replicated five times with 10 snails per replicate.
Results showed that for adults, the wormwood leaves methanolic extract was not statistically significant with the commercially available molluscicide, although 17.625% (T5) resulted in 82% mortality rate. For juveniles, the different extract concentrations resulted in 98 to 100% mortality, which were comparable to 0.0002% (2mg/L) niclosamide and were considered highly effective based on Reik & Keitz (1954) and European Agency for the Evaluation of Medicinal Products (EMEA). Thus, wormwood leaves methanolic extract has a promising molluscicidal activity against adult snails at a concentration of 17.625%, and at all concentrations for the juvenile snails of O. hupensis quadrasi. The LC50 of the adult and juvenile snails were 14.075% and 10.294%, respectively.
Secondary metabolites that were found positive during the qualitative phytochemical analysis with the extract were tannins, saponins, and terpenoids. The mortality of the snails can be attributed to the bioactivity of the secondary metabolites present that may be acting in combination or individually.

Keywords : Artemisia dubia, wormwood, Oncomelania hupensis quadrasi, molluscicide

Annals of Tropical Research 41(1):16-23(2019)