abdul gafur | Indonesian Capital Market and Financial Institution Supervisory Agency (Bapepam-LK) (original) (raw)
Papers by abdul gafur
Mycorrhiza, 2007
In order to characterise the effect of ectomycorrhiza on Na+-responses of the salt-sensitive popl... more In order to characterise the effect of ectomycorrhiza on Na+-responses of the salt-sensitive poplar hybrid Populus × canescens, growth and stress responses of Paxillus involutus (strain MAJ) were tested in liquid cultures in the presence of 20 to 500 mM NaCl, and the effects of mycorrhization on mineral nutrient accumulation and oxidative stress were characterised in mycorrhizal and non-mycorrhizal poplar seedlings exposed to 150 mM NaCl. Paxillus involutus was salt tolerant, showing biomass increases in media containing up to 500 mM NaCl after 4 weeks growth. Mycorrhizal mantle formation on poplar roots was not affected by 150 mM NaCl. Whole plant performance was positively affected by the fungus because total biomass was greater and leaves accumulated less Na+ than non-mycorrhizal plants. Energy dispersive X-ray microanalysis using transmission electron microscopy analysis of the influence of mycorrhization on the subcellular localisation of Na+ and Cl− in roots showed that the hyphal mantle did not diminish salt accumulation in root cell walls, indicating that mycorrhization did not provide a physical barrier against excess salinity. In the absence of salt stress, mycorrhizal poplar roots contained higher Na+ and Cl− concentrations than non-mycorrhizal poplar roots. Paxillus involutus hyphae produced H2O2 in the mantle but not in the Hartig net or in pure culture. Salt exposure resulted in H2O2 formation in cortical cells of both non-mycorrhizal and mycorrhizal poplar and stimulated peroxidase but not superoxide dismutase activities. This shows that mature ectomycorrhiza was unable to suppress salt-induced oxidative stress. Element analyses suggest that improved performance of mycorrhizal poplar under salt stress may result from diminished xylem loading of Na+ and increased supply with K+.
Ganoderma root rot is the most serious disease affecting commercially planted Acacia mangium in p... more Ganoderma root rot is the most serious disease affecting commercially planted Acacia mangium in plantations in Indonesia. Numerous Ganoderma spp. have been recorded from diseased trees of this species and to a lesser extent Eucalyptus, causing confusion regarding the primary cause of the disease. In this study, a large collection of Ganoderma isolates were obtained from the roots of A. mangium showing early signs of root rot in disease centres in South Sumatra plantations. Isolates were also collected from Eucalyptus roots at Lake Toba in North Sumatra showing similar symptoms as well as from sporocarps connected to these samples. Phylogenetic analyses showed that a single Ganoderma sp., identified as G. philippii, is the major causal agent of Ganoderma root rot on A. mangium. Results from this study also showed that the isolates obtained for Eucalyptus trees in North Sumatra belong to G. philippii. Isolates from roots and connected fruiting bodies together with the morphology of the fruiting structures confirmed this identification. Symptoms associated with this pathogen are obvious and it should not be confused with other diseases. Other Ganoderma spp. found in disease centres are considered to be of minor importance and management strategies for root rot should be focused on G. philippii.
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Ambio, 2003
An integrated socioeconomic and erosion study on the sustainability of traditional shifting culti... more An integrated socioeconomic and erosion study on the sustainability of traditional shifting cultivation (Jhum) carried out in 1998 and 1999 in the Chittagong Hill Tracts (CHT) of Bangladesh showed the system to be nonsustainable under the current conditions with fallow periods of only 3-5 years and lack of land rights. An estimated input (mainly labor) of USD 380 ha(-1) yr(-1) results in only a total output of USD 360 ha(-1) yr(-1) and Jhum cultivated areas suffer severe loss of soil and valuable plant nutrients along with runoff during the rainy season. To compensate these losses by commercial fertilizers will cost nearly USD 2 million yr(-1) for CHT. To ensure long-term productivity of the soils, Jhum should therefore be adjusted to a tolerable level and farmers should be given rights and title to the land to motivate them to switch to improved, settled farming systems.
Ambio, 2003
An integrated socioeconomic and erosion study on the sustainability of traditional shifting culti... more An integrated socioeconomic and erosion study on the sustainability of traditional shifting cultivation (Jhum) carried out in 1998 and 1999 in the Chittagong Hill Tracts (CHT) of Bangladesh showed the system to be nonsustainable under the current conditions with fallow periods of only 3-5 years and lack of land rights. An estimated input (mainly labor) of USD 380 ha(-1) yr(-1) results in only a total output of USD 360 ha(-1) yr(-1) and Jhum cultivated areas suffer severe loss of soil and valuable plant nutrients along with runoff during the rainy season. To compensate these losses by commercial fertilizers will cost nearly USD 2 million yr(-1) for CHT. To ensure long-term productivity of the soils, Jhum should therefore be adjusted to a tolerable level and farmers should be given rights and title to the land to motivate them to switch to improved, settled farming systems.
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Journal of Hydrology, 2003
The effect of traditional shifting cultivation practices using slash and burn (locally known as J... more The effect of traditional shifting cultivation practices using slash and burn (locally known as Jhum) on runoff and losses of soil and nutrients was investigated over two years in three apparently similar small neighboring watersheds of approx. 1 ha each in the Chittagong Hill Tracts (CHT) of Bangladesh. The experiment used a paired catchment approach, comparing the effect of a one-year clearing/cultivation with long-term fallow and mixed perennial vegetation. In the year of cultivation, peak discharges increased considerably and the loss of soil and nutrients were significantly accelerated. The median peak discharge increased by a factor 7 and annual runoff increased by approx. 16%. The direct runoff from small watersheds under long-term fallow and/or perennial vegetation may typically vary between 15 and 24% of the annual rainfall. The loss of soil material from watersheds under mixed perennial vegetation or fallow is typically about 3 Mg ha -1 y -1, whereas the loss during the year of cultivation was about 6 times higher. But as indicated by the sediment delivery ratio of 0.57, a sizeable part of the soil lost from the uplands was deposited in the lower part of the main drainage line within the watershed. The soil loss from the upland part of the watershed was therefore approx. 30 Mg ha -1 yr -1, while the regional average sediment yield associated with shifting cultivation in the CHT is estimated to be 1.2 Mg ha -1 y -1, considerably lower than previous estimates. The depletion of soil organic matter and nutrients in the upland area was considerable, with sediment enrichment ratios in excess of unity. It is conservatively estimated that the net depletion of soil organic matter in the upland part of the watershed, resulting from the combined effects of slash and burn and erosion during the one year of cultivation, is at least 7%. Shifting cultivation practice in the CHT is associated with a high degree of hydraulic resilience, as indicated by the return of the flow regime and the rate of soil loss to near 'normal' levels already in the first year of fallow after one year of cultivation. The implications of the findings for the interpretation of previous soil erosion and soil loss estimates in the region and for development planning are discussed.
Puji syukur kami ucapkan kehadirat Allah SWT, karena berkat rahmat-Nya kami bisa menyelesaikan ma... more Puji syukur kami ucapkan kehadirat Allah SWT, karena berkat rahmat-Nya kami bisa menyelesaikan makalah yang berjudul "Teori Pembelajaran Konstruktivisme". Makalah ini disusun guna memenuhi tugas Kelompok mata kuliah Strategi Belajar Mengajar. Dalam makalah ini kami akan memaparkan bagaimana mengajar menggunakan Teori Pembelajaran Konstruktivisme. Kami sampaikan terimakasih kepada Ibu Siti Mawaddah, M.Pd selaku dosen mata kuliah Strategi Belajar Mengajar yang telah memberikan pengarahan dalam penyelesaian tugas ini, sehingga tugas ini tersusun dengan baik.
Mycorrhiza, 2007
In order to characterise the effect of ectomycorrhiza on Na+-responses of the salt-sensitive popl... more In order to characterise the effect of ectomycorrhiza on Na+-responses of the salt-sensitive poplar hybrid Populus × canescens, growth and stress responses of Paxillus involutus (strain MAJ) were tested in liquid cultures in the presence of 20 to 500 mM NaCl, and the effects of mycorrhization on mineral nutrient accumulation and oxidative stress were characterised in mycorrhizal and non-mycorrhizal poplar seedlings exposed to 150 mM NaCl. Paxillus involutus was salt tolerant, showing biomass increases in media containing up to 500 mM NaCl after 4 weeks growth. Mycorrhizal mantle formation on poplar roots was not affected by 150 mM NaCl. Whole plant performance was positively affected by the fungus because total biomass was greater and leaves accumulated less Na+ than non-mycorrhizal plants. Energy dispersive X-ray microanalysis using transmission electron microscopy analysis of the influence of mycorrhization on the subcellular localisation of Na+ and Cl− in roots showed that the hyphal mantle did not diminish salt accumulation in root cell walls, indicating that mycorrhization did not provide a physical barrier against excess salinity. In the absence of salt stress, mycorrhizal poplar roots contained higher Na+ and Cl− concentrations than non-mycorrhizal poplar roots. Paxillus involutus hyphae produced H2O2 in the mantle but not in the Hartig net or in pure culture. Salt exposure resulted in H2O2 formation in cortical cells of both non-mycorrhizal and mycorrhizal poplar and stimulated peroxidase but not superoxide dismutase activities. This shows that mature ectomycorrhiza was unable to suppress salt-induced oxidative stress. Element analyses suggest that improved performance of mycorrhizal poplar under salt stress may result from diminished xylem loading of Na+ and increased supply with K+.
Ganoderma root rot is the most serious disease affecting commercially planted Acacia mangium in p... more Ganoderma root rot is the most serious disease affecting commercially planted Acacia mangium in plantations in Indonesia. Numerous Ganoderma spp. have been recorded from diseased trees of this species and to a lesser extent Eucalyptus, causing confusion regarding the primary cause of the disease. In this study, a large collection of Ganoderma isolates were obtained from the roots of A. mangium showing early signs of root rot in disease centres in South Sumatra plantations. Isolates were also collected from Eucalyptus roots at Lake Toba in North Sumatra showing similar symptoms as well as from sporocarps connected to these samples. Phylogenetic analyses showed that a single Ganoderma sp., identified as G. philippii, is the major causal agent of Ganoderma root rot on A. mangium. Results from this study also showed that the isolates obtained for Eucalyptus trees in North Sumatra belong to G. philippii. Isolates from roots and connected fruiting bodies together with the morphology of the fruiting structures confirmed this identification. Symptoms associated with this pathogen are obvious and it should not be confused with other diseases. Other Ganoderma spp. found in disease centres are considered to be of minor importance and management strategies for root rot should be focused on G. philippii.
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Ambio, 2003
An integrated socioeconomic and erosion study on the sustainability of traditional shifting culti... more An integrated socioeconomic and erosion study on the sustainability of traditional shifting cultivation (Jhum) carried out in 1998 and 1999 in the Chittagong Hill Tracts (CHT) of Bangladesh showed the system to be nonsustainable under the current conditions with fallow periods of only 3-5 years and lack of land rights. An estimated input (mainly labor) of USD 380 ha(-1) yr(-1) results in only a total output of USD 360 ha(-1) yr(-1) and Jhum cultivated areas suffer severe loss of soil and valuable plant nutrients along with runoff during the rainy season. To compensate these losses by commercial fertilizers will cost nearly USD 2 million yr(-1) for CHT. To ensure long-term productivity of the soils, Jhum should therefore be adjusted to a tolerable level and farmers should be given rights and title to the land to motivate them to switch to improved, settled farming systems.
Ambio, 2003
An integrated socioeconomic and erosion study on the sustainability of traditional shifting culti... more An integrated socioeconomic and erosion study on the sustainability of traditional shifting cultivation (Jhum) carried out in 1998 and 1999 in the Chittagong Hill Tracts (CHT) of Bangladesh showed the system to be nonsustainable under the current conditions with fallow periods of only 3-5 years and lack of land rights. An estimated input (mainly labor) of USD 380 ha(-1) yr(-1) results in only a total output of USD 360 ha(-1) yr(-1) and Jhum cultivated areas suffer severe loss of soil and valuable plant nutrients along with runoff during the rainy season. To compensate these losses by commercial fertilizers will cost nearly USD 2 million yr(-1) for CHT. To ensure long-term productivity of the soils, Jhum should therefore be adjusted to a tolerable level and farmers should be given rights and title to the land to motivate them to switch to improved, settled farming systems.
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Journal of Hydrology, 2003
Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivat... more Erratum to "Runoff and losses of soil and nutrients from small watersheds under shifting cultivation (
Journal of Hydrology, 2003
The effect of traditional shifting cultivation practices using slash and burn (locally known as J... more The effect of traditional shifting cultivation practices using slash and burn (locally known as Jhum) on runoff and losses of soil and nutrients was investigated over two years in three apparently similar small neighboring watersheds of approx. 1 ha each in the Chittagong Hill Tracts (CHT) of Bangladesh. The experiment used a paired catchment approach, comparing the effect of a one-year clearing/cultivation with long-term fallow and mixed perennial vegetation. In the year of cultivation, peak discharges increased considerably and the loss of soil and nutrients were significantly accelerated. The median peak discharge increased by a factor 7 and annual runoff increased by approx. 16%. The direct runoff from small watersheds under long-term fallow and/or perennial vegetation may typically vary between 15 and 24% of the annual rainfall. The loss of soil material from watersheds under mixed perennial vegetation or fallow is typically about 3 Mg ha -1 y -1, whereas the loss during the year of cultivation was about 6 times higher. But as indicated by the sediment delivery ratio of 0.57, a sizeable part of the soil lost from the uplands was deposited in the lower part of the main drainage line within the watershed. The soil loss from the upland part of the watershed was therefore approx. 30 Mg ha -1 yr -1, while the regional average sediment yield associated with shifting cultivation in the CHT is estimated to be 1.2 Mg ha -1 y -1, considerably lower than previous estimates. The depletion of soil organic matter and nutrients in the upland area was considerable, with sediment enrichment ratios in excess of unity. It is conservatively estimated that the net depletion of soil organic matter in the upland part of the watershed, resulting from the combined effects of slash and burn and erosion during the one year of cultivation, is at least 7%. Shifting cultivation practice in the CHT is associated with a high degree of hydraulic resilience, as indicated by the return of the flow regime and the rate of soil loss to near 'normal' levels already in the first year of fallow after one year of cultivation. The implications of the findings for the interpretation of previous soil erosion and soil loss estimates in the region and for development planning are discussed.
Puji syukur kami ucapkan kehadirat Allah SWT, karena berkat rahmat-Nya kami bisa menyelesaikan ma... more Puji syukur kami ucapkan kehadirat Allah SWT, karena berkat rahmat-Nya kami bisa menyelesaikan makalah yang berjudul "Teori Pembelajaran Konstruktivisme". Makalah ini disusun guna memenuhi tugas Kelompok mata kuliah Strategi Belajar Mengajar. Dalam makalah ini kami akan memaparkan bagaimana mengajar menggunakan Teori Pembelajaran Konstruktivisme. Kami sampaikan terimakasih kepada Ibu Siti Mawaddah, M.Pd selaku dosen mata kuliah Strategi Belajar Mengajar yang telah memberikan pengarahan dalam penyelesaian tugas ini, sehingga tugas ini tersusun dengan baik.