Mohd Amin Mohd Soom

Identification of homogenous regions in Gorganrood basin (Iran) for the purpose of regionalization

Estimation of flood in basins with poor condition of hydrometric stations as in quantity and quality is a dominant problem around the world, mainly in developing country where lack of funds and human resources cause more limitation in number of gauging stations. One of the areas that experience frequent floods and also suffer from small number of stations in Iran is Gorganrood basin. So there is a great need for the estimation and prediction of runoff in this area to prevent any future floods. Due to insufficient station in this area, direct prediction of flood is not applicable. Regional flood frequency analysis is a practical and widely used solution for these situations, which involves the identification of homogenous regions. Gorganrood region was hydrologically homogenized according to the extracted parameters that influence the floods. One of these parameters was Normalized Difference Vegetation Index (NDVI) driven from MODIS images. Curvature is another parameter that relates to topographic attributes. From factor analysis, the most appropriate variables were selected. According to these parameters (NDVI, curvature, area, slope…), the regions were classified into homogenous regions. For the purpose of homogenization, hierarchical (wards) clustering, fuzzy clustering and Kohonen method were applied. L-moment technique was used for the investigation of the results. The heterogeneity measure for one of the groups (Group 1) was more than two; therefore some modifications were applied. The region was grouped into two homogenous subregions. All of the clustering methods showed same results. The models showed that class 4 of NDVI is influential on flood in some return periods. The resulted models can be applied in future studies in different aspects of practical hydrology.

The importance of sullage (grey‐water) treatment in the restoration and conservation of urban streams

Abstract Sullage (grey‐water) is one of the major point pollution sources, which is discharged from residential and commercial areas into the rivers without any treatment. This study was conducted to determine the pollution characteristics of sullage from a 6.14‐hectare residential area where it is discharged into an urban stream without any treatment; and thereafter, to evaluate its probable consequences on the water quality of urban streams. Analyses of the hourly samples revealed that the sullage from residential area was polluted due to high concentration of BOD, COD, Ammoniacal Nitrogen (AN), Orthophosphate (PO4) and TKN, and low concentration of DO. Mean concentrations of the above‐mentioned parameters from 72 samples were 51, 123, 5.4, 2.15, 2.15 and 1.62 mg/l, respectively. Further analyses of data revealed that, on average, the sullage was equivalent to Class V water as defined by the water quality index (WQI) in National Water Quality Standards (INWQS) of Malaysia. Most of the urban streams drain return water (wastewater) from the settlements and lack adequate baseflow to dilute the wastewaters. As such, if the return waters are not treated then the urban streams shall never be able to achieve the required goals. Domestic sewage and industrial wastewaters are treated to some extent, to achieve the standards stated in Environmental Quality Act, 1979. On the contrary, although quantity and quality of sullage plays important role on stream water quality, it is neither taken care of by any agency nor controlled by any standard. As such, it is important to make necessary technical, institutional and legal arrangement to treat sullage up to certain standard before it find its way into the urban streams.

Relationship between apparent electrical conductivity and soil physical properties in a Malaysian paddy field

Site-specific crop management, well-established in some developed countries, is now being considered in developing countries such as Malaysia. The apparent electrical conductivity (ECa) of the soil can be used as an indirect indicator of a number of soil physical properties and even crop yield. Commercially available ECa sensors can efficiently develop the spatially dense data sets desirable in describing within-field spatial soil variability for precision farming. The main purpose of this study was to generate a variability map of soil ECa within a Malaysian paddy field using a VerisEC sensor. The ECa values were then compared with some soil variables within classes after delineation. Measured parameters were mapped using the kriging technique and their correlation with soil ECa was determined. The study showed that the VerisEC can determine soil spatial variability, and can acquire soil ECa information quickly. Spatial variability of shallow and deep ECa showed the same patterns. Estimation of soil properties based on ECa varied from one soil parameter to another and all could be estimated better by deep ECa. Cross-validation results showed that shallow and deep ECa, and also bulk density, gave more accurate estimates compared with other variables.

Physiological Analysis of Stoop Lifting Based on Heart Rate for the Malaysian Population

The growing problem of work related back injuries has contributed to the rising cost of health care, human suffering and loss of productivity. In Malaysia, back pain injury awareness is still low, but the number of casualties as a result of back pain is increasing. In this study, the physiological aspects of stoop lifting posture on heart rate for the Malaysian population were studied. Different lifting heights, frequency, twist angle and weight of loads were studied to identify and recommend the appropriate lifting tasks to be used by the workers. An experimental work was conducted involving 36 subjects between 20 and 40 years old with no history of back pain. The subjects performed stoop lifting posture to lift loads of 10, 15, 20 and 23 kg to a lifting height of 70 cm and 130 cm, with the frequency of 1 lift, 3 lifts and 6 lifts per minute and twist angle of 0° and 90°. The results of the study showed that heart rate is linearly related to height of lifting, weights, frequency and angle of twisting. These findings can be used as a guide to design lifting tasks for the Malaysian population.

Comparative Study on the Performance of Rice Seedlings Raised by Single Seedling Nursery Tray Method and Conventional System

Rising of rice seedlings is among the important factors responsible for better growth and development of rice plants as well as increasing the grain yield. Conventional method of raising rice seedlings requires larger space, time (24 hours seed soaking and 34 hours in jute bag up to sprouting) and labour intensive procedure, which limits the production capacity of rice seedlings. Transplanted seedlings raised by newly developed single seedling nursery tray have not been compared with the conventional system in the field so far. The objective of this study was to evaluate the average number of tillers per hill at 60-days after transplanting (DAT). The experimental design was one treatment [newly developed single seedling nursery tray (T1)] and three replications. The age of the seedlings raised by the newly developed single seedling nursery tray at the time of transplantation was 8 days. Plants were randomly selected and number of tillers were counted and recorded at 60 DAT from each treatment plot for further analysis. Average number of tillers (32.27 tillers/hill) in the case of the conventional system at 60 DAT using 8 days old seedlings was collected from previously published data. One sample T test was used to analyse the data using SPSS statistical analysis software (version 21) at 95% Confidence Levelof the Difference. The result of the analysis showed significant difference between them, with larger average number of tillers in T1 (68.56 tillers/hill) than the existing average number of tillers. The study depicted that using the newly developed single seedling nursery tray is one of the options to increase the number of tillers in SRI farming in order to increase the number of effective tillers, number of panicles, straw yield and grain yield of rice plants.

Spatial soil analysis using geostatistical analysis and map Algebra

Evaluating soil spatial variability through sampling is an important step in precision farming processes that aids farmers to make informed decisions on the spread of agricultural inputs. Manual sampling is essential in ascertaining soil physical characteristics and could be used to monitor the chemical components like macronutrient nitrogen (N), phosphorus (P), and potassium (K). This type of sampling however could be costly and time consuming in macronutrient sampling. In order to show the ability of manual sampling to capture the essence of variability in the agricultural fields with enough number of samples and therefore, helping the precision farming process, we conducted an experiment on different designs of random, systematic, stratified random, stratified systematic, and different sizes of samples. The experiment was carried out on the geostatistical surfaces (base maps) created from a set of data which belonged to a rice plantation in Malaysia. A krigged map for each of these schemes was created and compared with the N, P, and K base maps. The results showed that the systematic and stratified systematic schemes were the most accurate sampling schemes in terms of estimation of mean. However, both stratified schemes were not successful to create the standard deviation of populations. Concerning the standard error of mean when the schemes were used in linear mixed effect modeling grouped by the sample size, stratified samples could produce lower standard error (except for stratified random sample of P). In terms of reproducing the original spatial variability, only systematic sampling scheme could create better accuracy in most cases. The result also revealed that the most important property of a sampling scheme in the study area is representativeness of samples, and the number of samples does not play an important role in accuracy and map making. Therefore, the data could be equally valid for the precision farming.