Category Archives: Volume 27 No. 2 (2005)

Status of phosphorus in the rain forest ecosystem of Mt. Pangasugan, Leyte, Philippines


Author(s): Janice P. Susaya1 and Victor B. Asio1,2

Abstract

Phosphorus (P) is generally considered to be the most limiting mineral nutrient in tropical soils. This study was conducted to determine the amounts of Pin various components of the rainforest ecosystem. Composite samples of rocks, soil, stream sediments, stream water, rainwater, leaves of dominant vegetation, forest litter, wood and moss were randomly collected from a portion of the rain forest in Mt. Pangasugan, Leyte, Philippines. Samples were analyzed for their total P contents.
Findings revealed that P concentration varied substantially in the various ecosystem components evaluated. Higher P concentrations were found in the biosystem components particularly in the leaves of the vegetation than in the geosystem components. The P concentrations decreased in the following order: fresh leaves > moss > litter > soil > sediment >rock > wood > stream water > rainwater. Trace amount of P is brought into the ecosystem by rain. On the other hand, considerable amounts of P are found in the stream water and stream sediments which represent P losses from the rainforest ecosystem. This substantial loss of P is attributed to human disturbance in the forest ecosystem.

Keywords : phosphorus status, rain forest ecosystem, nutrient cycling

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Physical and chemical characteristics of two wetlands in Lake Danao Natural Park, Ormoc City


Author(s): Nadia P. Alfante and Teofanes A. Patindol

Abstract

The study was conducted to characterize the wetlands located at Sitio Quinto Limbo and Tasakan in Lake Danao Natural Park, Ormoc City based on some physicochemical parameters.
The two wetlands are generally shallow. Salinity ranged from 0.3 to 0.5 ppt which is characteristic of an oligohaline wetland. Sediment and water were slightly acidic. Concentrations of ammonium ions were lower than the normal value. Levels of nitrate and phosphate ions exceeded the normal value of 1mg/L and 0.025 mg/L, respectively.
Lead ion concentrations were generally within the normal range (10-100 mg/kg). Mean cadmium ion concentration was normal (0.01-1.0 mg/kg) although in some sites concentrations beyond the normal range were observed.
Based on the findings, it is recommended that conservation program be urgently implemented in the study area to ensure the conservation of the wetlands and their resources.

Keywords : Lake Danao Natural Park, physico-chemical characteristics, salinity

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Biology of Coccinella transversalis Muls. (Coleoptera: Coccinellidae)


Author(s): Brenda C. Balbarino and Ma. Juliet C. Ceniza

Abstract

The biology of Coccinella tranversalis reared on black bean aphid, Aphis craccivora was studied in the laboratory. The beetle passed through the egg, 4 larval instars, pupa and adult stages. The eggs were spindle-shaped and had an incubation of 2-3 days with an average of 2.85 days. The larvae which were typically black with orange bands or tinge on the methoracic region and some part of the abdomen had a total development period of about 6-9 days, with an average of 7.27 days. The pupal period lasted for about 3-4 days, or 3.83 days on the average. The total developmental period from egg to adult emergence took about 13-15 days. The adults which were typically red orange with black inverted v markings on the elytra lived for an average of 51.34 days. The female laid an average of 1000 eggs under laboratory conditions.

Keywords : Coccinellidae, Coccinella transversalis, biology of coccinellid beetle, Aphis craccivora

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Effect of dates of sowing on dry matter production and partitioning in yam bean (Pachyrrhizus erosus (L) Urban)


Author(s): M. Nedunchezhiyan and R. C. Ray

Abstract

Climatic factors like temperature, relative humidity, rainfall, day length, and soil edaphic factors influence the growth and yield of a crop. The rate of dry matter accumulation remains faster at higher than lower temperature. However, high temperatures decrease the proportion of dry matter translocated to the tuber. Hence a field experiment was conducted in 1995 to 1996 at the Regional Centre of Central Tuber Crops Research Institute, Bhubaneswar to study the effect of climatic factors on dry matter production and partitioning in yam bean (Pachyrritizits erosus (L) Urban). The results revealed no genotypic differences in dry matter production and yield, indicating that all genotypes used were equally efficient in dry matter production and partitioning, However, date of sowing has marked influence on dry mater production and yield. Sowing on the 17th of August led to the production of higher dry matter with the highest tuber yield comparable with those sown on the 1st of September because of their higher partitioning efficiency. Although the partitioning efficiencies of the October 1st and September 16th sowings were higher, these resulted in lower yield due to lack of sufficient dry matter. These findings clearly indicated that early sowing between the 17th of August and the 1st of September is essential for higher tuber yield in fertile acid laterite soil.

Keywords : distribution ratio, dry matter production, partitioning, yield

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Evaluation of a simple re-circulating hydroponic system for sweet pepper (Capsicum annum L.) and pechay (Brassica napus L.)


Author(s): Misael T. Diputado, Jr.1, Manolo B. Loreto, Jr.2 and Jonathan I. Mangmang1

Abstract

This study assessed the growth, yield and profitability of sweet pepper and pechay grown in a simple, locally designed re-circulating hydroponics system (RHS) provided with coarse river sand and coco-coir dust as aggregates at different ratios. The system consisted of 6 pans (40-cm wide, 2.2 m long, 10 cm deep) made of galvanized iron (G.I.) sheets. The nutrient solution is delivered from a plastic drum by gravity to the aggregates through a system of polyvinyl chloride (PVC) pipes provided with small holes. Each end of the pan is provided with a hole where excess solution drains into a collecting container, which is then re-circulated back into the drum. The performance of the crops under this system was compared to those grown under the conventional (soil-grown), and Simple Nutrient Addition Program (SNAP) hydroponics system.
Pechay plants grown in the RI-1S were taller, produced more leaves, had faster growth and development and had higher yield compared to those grown in SNAP hydroponics and conventional system. Sweet pepper plants grown in the RHS also had better growth and higher yield compared to the SNAP hydroponics and conventional production systems. The ratio of coarse sand and coco-coir dust as aggregate for the RHS did not significantly affect growth and yield of the two crops. A projected cost and return analysis considering a pechay-pechay-sweet pepper-pechay-pechay-sweet pepper 1-year crop rotation scheme revealed that the use of RHS had higher profitability compared to the other two production systems.

Keywords : sweet pepper, pechay, hydroponics, coco-coir dust

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Farmers’ knowledge and adoption of sustainable land-use management systems in Matalom, Leyte, Philippines


Author(s): Fe M. Gabunada1 and Agnes C. Rola2

Abstract

This study compared the knowledge levels between adaptors and non-adaptors of sustainable land-use management system in Matalom, Leyte, investigate the influence of farrners’ knowledge and other factors on the extent of adoption of technologies, and identify implications that may enhance technology adoption.
The sustainable land-use management systems considered in this study included contour hedgerow and agroforestry technologies. The adoptors of sustainable land-use management systems have significantly higher knowledge than the non-adoptors. Their knowledge is significantly and positively affected by their level of education, attendance to related trainings, and contact with extension agents.
Results of the Tobit regression analysis showed that the extent of adoption of sustainable land-use management system in the study area is significantly and positively influenced by farmers’ knowledge and other factors such as access to credit and membership in alayon (labor-sharing group)

Keywords : Farmers’ knowledge, sustainable land-use management systems

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