Judul: Analisis Salinitas dan Dampaknya terhadap Produktivitas Padi di Wilayah Pesisir Indramayu
Abstrak: Indramayu District is one of main rice production centre in West Java. Most of rice fields locate next to Java’s North Coast and some of the areas are influenced by salinity problem. The problem of salinity increases during dry season particularly when irrigation water is limited as salt water intrusion will increases under this condition. The salinity problem will be more severe when dry season extends. Under high salinity condition, yield of rice will decrease significantly. This study analyzed the spatial distribution of salinity and its changes in the rice field during dry season and its impact on rice yield. The salinity were measured during dry season (July, October and November) in a number of location and yield of rice was measured in the same location from a plot with size of area of size 2.5x2.5 m2 in November. It was found that the salinity decreased with distance from the coast. In some area near the cost, the salinity could go up to 9 dS/m and most this area had been converted to pond or salt mining or other uses. In most of paddy fields affected by salinity have salinity level of less than 5.5 dS/m. The area of paddy field affected by salinity expanded as the rainfall in the dry season decreased. The rice yield was not significantly affected by the salinity. This study suggests that the current rice variety used by farmers is tolerant to salinity. However, the risk of salinity may increase in the future due to change in sea level and coastal characteristics (e.g. degradation and conversion of mangrove forests). Current rice variety may be tolerant to salinity of not more than 5.5 dS/m. Adapting to increasing risk of salinity, it is very important to introduce alternative rice varieties which are more tolerant to salinity, restoration of mangrove forest and also improvement of irrigation facilities.
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Judul: Efisiensi Produksi Usaha Garam Rakyat di Kabupaten Indramayu
Abstrak: Indramayu is one of salt production center in West Java with character of having higher rainfall. Some problems faced by Indramayu, such as low farm gate price and fluctuating production level. These problems have caused farmers do not get any profit or having business inefficiency and higher business cost. The aims of the research carried out are (1) to identify the production factors that affecting the salt production, (2) to analyse the resources of efficient production techniques, (3) to analyse the economic and allocation efficency level of of salt production in Indramayu. Data was collected from 100 farmers, divided into 3 groups based on tenurial ownership (selected by multistage sampling technique and analysed using statistic inferencial) with production function Cobb-Douglas stochastic-frontier and cost function. The probability of OLS resulted RTS which salt production in increasing return to scale area where RTS of cash-rent farmers 2.670, share-rent farmers 1.350 and farmers owner-tenant 1.153. Farm size is the most responsive production factor to increase the production level. Technical and allocation inefficiency affected the salt production as described by estimation of gamma which significant in each of farmer’s type. The parameter of gamma shows 80.1%, 99% of output variances of salt business among the cash-rent farmers, share-rent and owner-tenant farmers is the difference in technical efficiency. The result of research also showed that increasing of farm size, income and access of capital loan in labour-farmer, significantly causing the efficiency increasement. The use of additives could also increase the efficiency of self-own farmers. The average of technical efficinecy is 68% in scale of 0.7 and the rest is under this scale. The allocation efficiency level is only 5% out of total samples which is dominated by farmers owner-tenant. With optimalisation test of production input through ratio of product marginal value of cost (in output price Rp. 450/kg), showed that the land and human resource factor is more than 1 which means it is needed to add farm size and human resources quality. The phenomena of high technical efficiency and low allocation and economic efficiency is the characters of agribusiness which still has problem in high price production input and low output price. By reducing the level of fuel for providing the sea water, it is able to increase the allocation efficiency of salt production. The farmers could do substitution by using the low cost technology of sea water supplier. The policy of extensification of salt-farm is one of strategies to increase the salt production and the intensification policy is improvement of infrastructures and technologies that could increase the production quantities with the available land
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf