Over the past decade, rice (Oryza sativa or Oryza glaberrima) cultivation has increased in many rice-growing countries due to the increasing export demand and population growth and led to a copious amount of rice residues, consisting mainly of rice straw (RS) and rice husk (RH), being generated during and after harvesting. In this study, Eudrilus eugeniae was used to decompose rice residues alone and rice residues amended with cow dung (CD) for bio-transformation of wastes into organic fertilizer. Generally, the final vermicomposts showed increases in macronutrients, namely, calcium (11.4-34.2%), magnesium (1.3-40.8%), phosphorus (1.2-57.3%), and potassium (1.1-345.6%) and a decrease in C/N ratio (26.8-80.0%) as well as increases in heavy metal content for iron (17-108%), copper (14-120%), and manganese (6-60%) after 60 days of vermicomposting. RS as a feedstock was observed to support healthier growth and reproduction of earthworms as compared to RH, with maximum adult worm biomass of 0.66 g/worm (RS) at 60 days, 31 cocoons (1RS:2CD), and 23 hatchlings (1RS:1CD). Vermicomposting of RS yielded better results than RH among all of the treatments investigated. RS that was mixed with two parts of CD (1RS:2CD) showed the best combination of nutrient results as well as the growth of E. eugeniae. In conclusion, vermicomposting could be used as a green technology to bio-convert rice residues into nutrient-rich organic fertilizers if the residues are mixed with CD in the appropriate ratio.
This study was undertaken to determine the effects of varied salinity regimes on the morphological traits (plant height, number of leaves, number of flowers, fresh and dry weight) and major mineral composition of 13 selected purslane accessions. Most of the morphological traits measured were reduced at varied salinity levels (0.0, 8, 16, 24 and 32 dS m(-1)), but plant height was found to increase in Ac1 at 16 dS m(-1) salinity, and Ac13 was the most affected accession. The highest reductions in the number of leaves and number of flowers were recorded in Ac13 at 32 dS m(-1) salinity compared to the control. The highest fresh and dry weight reductions were noted in Ac8 and Ac6, respectively, at 32 dS m(-1) salinity, whereas the highest increase in both fresh and dry weight was recorded in Ac9 at 24 dS m(-1) salinity compared to the control. In contrast, at lower salinity levels, all of the measured mineral levels were found to increase and later decrease with increasing salinity, but the performance of different accessions was different depending on the salinity level. A dendrogram was also constructed by UPGMA based on the morphological traits and mineral compositions, in which the 13 accessions were grouped into 5 clusters, indicating greater diversity among them. A three-dimensional principal component analysis also confirmed the output of grouping from cluster analysis.
Toxic cyanobacteria blooms are increasing in magnitude and frequency worldwide. However, this issue has not been adequately addressed in Malaysia. Therefore, this study aims to better understand eutrophication levels, cyanobacteria diversity, and microcystin concentrations in ten Malaysian freshwater lakes. The results revealed that most lakes were eutrophic, with total phosphorus and total chlorophyll-a concentrations ranging from 15 to 4270 µg L(-1) and 1.1 to 903.1 µg L(-1), respectively. Cyanobacteria were detected in all lakes, and identified as Microcystis spp., Planktothrix spp., Phormidium spp., Oscillatoria spp., and Lyngbya spp. Microcystis spp. was the most commonly observed and most abundant cyanobacteria recorded. Semi-quantitative microcystin analysis indicated the presence of microcystin in all lakes. These findings illustrate the potential health risk of cyanobacteria in Malaysia freshwater lakes, thus magnifying the importance of cyanobacteria monitoring and management in Malaysian waterways.
Soybean (Glycine max L.) is one the most commonly consumed legumes worldwide, with 200 million metric tons produced per year. However, the inedible soy husk would usually be removed during the process and the continuous generation of soybean husk may represent a major disposal problem for soybean processing industries. Thus, the main aim of the present study was to investigate the possibility to convert soybean husk (S) amended with market-rejected papaya (P) into vermicompost using Eudrilus eugeniae.