Judul: The adoption of conservation farming system of potatoes farming in the dryland of Upland Pangalengan, Bandung
Abstrak: Soil erotion is a serious problem in upland Pangalengan, Bandung. A study was carried out to determine factors affecting adoption of conservation farming practices, to analize factors that influence its production and to analyze impact of conservation farming practices in soil fertility and potatoes farmer's income. The data for study analysis is collected from cross-sectional data of farm households.
Keyword: Soil conservation, Upland potatoes farming, Jawa Barat, Erosi, SCUAF, Pembangunan pertanian

Judul: Potato based sustainable vegetable farming systems planning in Siulak watershed, Kerinci district, Jambi
Abstrak: Established agricultural practices in upland vegetable growing areas in Indonesia are generally implementing up and down the slope cultivation with relatively high rates of fertilizers and pesticides applications. Combined with high rainfall intensity, these practices have contributed to high runoff and severe erosion and in turn gradually decreased land productivity and farmers income, thus unsustainable farming systems. The objectives of this research were : 1) to identify and describe existing conditions of the potato based vegetable farming systems, 2) to study soil conservation measures alternatives to control soil erosion and obtain optimal net farm income, and 3) to design potato based sustainable vegetable farming systems in Siulak Watershed, Kerinci District, Jambi Province. Land biophysical and farmers characteristics as well as agrotechnologies were identified through soil survey and farmers interview, while alternatives of soil conservation measures were studied through soil erosion plot experiments. Models of patato based sustainable vegetable farming system were formulated by simulation using Universal of Soil Loss Equation (USLE) model and multiple goal programming. Results of the research showed that up and down the slope vegetable farming practices and inadequate of soil conservation practices caused soil erosion rate of 39.25 - 229.14 ton/ha/year which was higher than the local soil tolerable loss (24.09 - 20.89 ton/ha/year), and net farm income was generally not enough to support life worthed living (Rp 28 000 000/year). Planting on ridges across the slope, or ridges constructed 15 degrees across the slope, or in ridges down the slope with a mound constructed across the slope in each 4.5 m distance and silt-pit, can be considered as alternatives soil conservation methods for vegetable farming systems. Potato based sustainable vegetable farming systems in Siulak Watershed could be accomplished by improving the cultivation practices by integrating the soil conservation methods (planting on ridges across the slope and mulch, or ridges down the slope with a mound constructed across the slope, mulch and silt-pit) into the existing systems. Potato based sustainable vegetable farming systems with the cropping pattern of potato-cabbage-tomato and recommended agrotechnologies performed the most optimum models in Siulak Watershed, Kerinci District, Jambi; this system generated soil erosion about 10.59 - 18.82 ton/ha/year and the net farm income about Rp 40 714 558 - Rp 52 745 652 per hectar per year on 0.44 ha farm area. Some farmers in Siulak Watershed have started applicating the recommended agrotechnologies right after the research was completed.
Keyword: farming systems, Siulak Watershed, Kerinci District, Jambi

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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