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Projection of Rice Blast Diseases in West Java Region based on Climate Change Scenario
Full text linkRice production in Indonesia has faced many challenges including disease outbreak leading to crop failure. Blast is a common disease, which is often found in paddy, that able to inhibit its growth and development. Here, we present simulation modeling to predict blast outbreak under climate change projection scenario in west Java, Indonesia. Two climate projections namely RCP4.5 and RCP8.5 were employed as input for EPIRICE epidemiological model. With this model we anaysed the potency of blast outbreak for 2021-2050. Then we compared the area of the projected blast with the output from current climate condition (1996-2005, as a baseline). Our results show that the potency of blast outbreak was in a low level under baseline. The area indicating a low level of outbreak was observed for both climate projections. Our findings revealed that a decreasing trend on the outbreak is expected for 2021-2050. However, an increased number of area having blast outbreak was observed especially in mountains region as many of 2%.day and 6%.day for RCP4.5 and RCP8.5, respectively.
Pengaruh Ketinggian Tempat dan Curah Hujan Pada Penyakit Diare (Studi Kasus: Kabupaten Bogor)
Full text linkThis study aimed to determine the effect of altitude and rainfall on the incidence of disease ( IR ) diarrhea, and to obtain threshold values of rainfall that often cause diarrhea. Determination category of normal rate of diarrhea IR is based on diarrhea IR by DINKES Bogor in the amount of 20-25/1000 population per year, while the determination of precipitation category is based on consideration of Oldeman climate classification. The results showed that there were two districts with very high levels of vulnerability i.e. Cisarua and Cijeruk, while the other regions only at a moderate level. The negative influence of altitude (or positive influence of temperature) on the IR will be evident if the analysis is separated between in the highlands (> 600 asl) and the lowlands (< 600 asl). This influence is significant, especially at altitudes above 600 meters above sea level. The correlation of the precipitation is significant negative linear to the incidence of diarrhea in the district Cisarua, Cibinong, Jonggol, and Jasinga. In districts Cibinong, Jonggol, and Jasinga, precipitation should be anticipated in the range of 100-200 mm/month, where moderate IR often occurs, while in the district Cisarua, is in the range of precipitation 300-400 mm/month, where high IR often occurs
Penentuan Awal dan Durasi Musim Kemarau Menggunakan Fungsi Polynomial dengan Aplikasi Visual Basic for Applications (VBA)
Full text linkForecasting the occurrence of the onset of dry season and its length is important in determining the availability of water for irrigation, domestic and industrial uses. The length of dry season is used for reference in calculating water demand. Prediction of drought can be studied based on the rainfall patterns that have occurred. This is possible because there is a tendency that the rain will repeat a certain pattern at a certain time. The purpose of this study was to predict the onset of dry and rainy seasons as well as their length. Determination of the onset of dry season and its length was conducted using polynomial function of the cumulative amount of rain every single day based on the rain data. The research was conducted using rainfall data from Climate Station III in Serang from 1989 to 2010. The sum of daily rainfall could form a polynomial function. If the magnitude of daily rainfall in a certain period of time is less than the slope of the cumulative annual rainfall, then at that time the dry season is occurred. Determination of the dry season peak can be done by finding the maximum (extreme) point from the polynomial function by getting the second derivative which value is close or equal to zero. In average, the dry season occurred in Serang city started on the 132nd until 300th day. Deviation value for the onset of dry and rainy seasons were 23 and 38 days, respectively, with an average of length of 168 days. The average of R2 value for polynomial function was 0.9937
Development of Early Detection Method for Drought and Flood on Rice Paddy
Full text linkDroughts and floods due to extreme climate events has caused yield loss in various regions of Indonesia, including the Provinces of Aceh and North Sumatra. An early detection model needs to be developed to anticipate the negative impacts of extreme climate event. The model may describe the association of surplus and rainfall deficits with paddy damage due to drought and flood. We used Standardized Precipitation Index (SPI) to explore drought and flood characteristics in period 1989-2016. The study aimed: (i) to analyze the relationship between SPI and paddy damage due to drought and flood events, (ii) to analyze the critical value of the duration and intensity of SPI which causes paddy damage, and (iii) to determine which districts were prone to drought and flood in the Provinces of Aceh and North Sumatra. The results concluded that SPI-3 and -6 months can better describe the frequency of drought and rice flooding. In addition, drought on paddy occured mostly if the SPI was smaller than -1 which took place within 4-5 months, whereas flood occured if the SPI was greater than 1. Short duration drought (2-3 months) were observed in five districts in Aceh (2) and North Sumatra (3). On other hand, more flood districts were identified (9 districts)
Kaitan Ruang Terbuka Hijau dengan Kenyamanan Termal Perkotaan
Full text linkThe existence of green open space in urban areas is very important in influencing the conditions of thermal comfort. The objective of this research was to analyze the relationship between green open space and human comfort for the city of Yogyakarta. We employed Temperature Humidity Index (THI) with input air temperature and relative humidity. The THI value was obtained from four green open space categories those are point, line, area and non-green space. The results showed that the green open space has a positive effect on lowering the air temperature through the cooling effect and providing more comfortable conditions than the place with non-green open space. Based on this research, the city of Yogyakarta could be categorized as quite comfortable
Comparison of Aerodynamic, Bowen-Ratio, and Penman-Monteith Methods in Estimating Evapotranspiration of Oil Palm Plantation
Full text linkOil palm is one important agricultural commodity that has high economic value. Oil palm productivity is significantly influenced by its water use (needs). Measurement and estimation of oil palm evapotranspiration is needed for determination of its water needs. Various methods are available and this study compare three methods, consisting of aerodynamic, Bowen-Ratio and Penman-Monteith methods in analyzing water needs/use of oil palms plantation located in PTPN VI Jambi. Peak of evapotranspiration rate occured in the afternoon around 13.00 and 14.00 local time. Bowen-Ratio method has higher estimation value of evapotranspiration than the other two methods. Ratio between evapotranspiration and global radiation of two and ten-years old oil palm plantations remain similar, around 47%. Penman Monteith method has the nearest estimation value to reference method (aerodynamic method) showed by the smallest RMSE value, 0.087 for two years oil palm and 0.157 for ten-years old oil palm
Evapotranspiration of Sandalwood (Santalum Album L.) Seedlings with Several Primary Host Plants
Full text linkSandalwood (Santalum album L.) seedlings planted with different primary host plants should require different amounts of water. In practice, however, sandalwood seedlings with different primary host plants are irrigated with similar amount of water. Thus, it is interesting to study the amount of water expressed as evapotranspiration for the sandalwood seedlings and their primary host plants because there are hemiparasitic symbiosis plants in one planting medium. The purpose of this research was to compare and analyse evapotranspiration (ET) and water use efficiency (WUE) of sandalwood seedlings with different primary host plants, namely chili (Capsicum annum), krokot (Alternanthera sp.), and sengon (Albizia chinensis). The experiment was conducted in a greenhouse and designed using completely randomized design. Results showed that different primary host plants already influenced ET at 6 days after sowing of primary host (DASH). The sandalwood seedlings with chili and krokot as primary hosts, had the highest ET during 6-22 DASH. From 24 to 36 DASH, ET for all types of host plants were similar. After 36 DASH, ET of sandalwood seeding with primary host sengon increased, and had the highest ET. Sandalwood seedling with primary host krokot had the highest WUE to produce sandalwood above ground biomass with value 0.3 g/l during the 0-3 weeks after sowing of primary host (WASH), 0.6 g/l during the 3-6 WASH, and 0.9 g/l during 6-9 WASH
Model Simulation of Soybean (Glycine Max (L.) Merrill) Growth by Energy Balance Approach
Full text linkIntercepted solar radiation by leaf will influence energy balance in plant. The energy balance in leaf is a complex process, which results in biomass growth. Here, we modeled leaf energy balance to estimate dry matter growth in soybean. In the field, we measured intercepted radiation in canopy (1 meter above surface) with two treatments: soybean with 50% shading (N50%M0) and no-shading (N0%M0) twice a week. Then we sampled a biomass with destructive technique every week in each treatment. Our results showed that the intercepted radiation in no-shading treatment was higher (400 J/m2) than those in shading one (250 J/m2). The results were consistence with the high biomass growth at 12 weeks after planting, which observed in no-shading treatment. Then we validated our model by 1:1 plot test. Our finding revealed that no-shading treatment showed a good agreement with the observed biomass (closed to 1:1 plot), whereas the shading treatment tended to predict under estimate of biomass
Determination of Thermal Comforts Threshold on Students and Domestic Tourists in Lombok Island
Full text linkThe research aims to identify the comfort level on Lombok island, and to determine the comfort threshold values based on various thermal indices for indoor and outdoor. We applied three different indices namely Wet-Bulb Globe Temperature (WBGT), Temperature Humidity Index (THI), and Heat Stress Index (HSI). We observed climate variables including air temperature, relative humidity, wind speed, and black-globe temperature for periode February-March 2018. Then we correlated the indices against comfort and heat perceptions. Our results showed that altitude has influenced on the comfort index. Location on the higher altitude will have low index values, which were consistent for all indices. For the comfort threshold values, adaptation to local climate is the key to determine the values. The adapted people (students) will have a higher threshold value than those whom they were tourists. Our finding revealed that the threshold values for the indices were 28.5, 27.5, 92 for WBGT, THI, HSI, respectively. Based on our statistical analysis, we found that HSI was the best index to determine the comfort level in Lombok for the observed period, as the HSI has strong correlation with comfort and heat perceptions. Further, we recommend the wider used of HSI as the index uses more easily obtained climate variables
Prediksi Awal Musim Hujan di Jawa Menggunakan Data Luaran Regional Climate Model Version 3.1 (RegCM3)
Full text linkMonsoon onset information plays an important role in setting up planting strategy for achieving optimum yield. This study aimed to develop forecasting model for the monsoon onset in main rice growing area of Java used Regional Climate Model Version 3.1 (RegCM3). The forecasting models of the monsoon onset and September-Oktober-November (SON) rainfall data were developed using regression model that have the highest coefficient determination and the models were tested using likelihood ratio test. It was found that the forecasting models of the monsoon onset and September-Oktober-November rainfall data were polynomial orde 2 or cuadratic that have coefficient determination 69%, 74%, 80% and 86%. Likelihood ratio test found that RegCM3 rainfall data was not significantly different with observation rainfall data (α = 0.05). Onset in Java between 25th until 34th of 10-days period (early September until early December)