Judul: Perfomance of Shallot Production at Various Levels of Soil
Pottasium Content in Andisol and Inceptisol
Abstrak: Hara merupakan faktor yang penting dalam pertumbuhan tanaman bawang merah. Salah satu hara utama yang mendukung pertumbuhan bawang merah adalah kalium. Penelitian bertujuan untuk mengetahui pertumbuhan bawang merah yang dibudidayakan pada berbagai tingkat kadar hara kalium di tanah andisol dan inceptisol. Penelitian dilakukan di Rumah Plastik Kebun Percobaan Tajur PKHT IPB, Kecamatan Bogor Selatan, Kota Bogor, Jawa Barat pada bulan Februari sampai September 2021. Metode yang digunakan pada penelitian adalah rancangan kelompok lengkap teracak (RKLT) faktorial dengan perlakuan jenis tanah dan kadar hara kalium. Peubah pengamatan yang diamati adalah tinggi tanaman, jumlah daun, jumlah anakan, rata-rata diameter, jumlah umbi per rumpun, bobot basah tanaman, bobot basah umbi, bobot kering tanaman, dan bobot kering umbi. Berdasarkan hasil penelitian didapatkan bahwa interaksi antara jenis tanah dan kadar hara K berpengaruh terhadap bobot basah tanaman, bobot basah umbi, bobot kering tanaman, bobot kering umbi. Hasil penelitian juga menunjukkan bahwa secara umum pertumbuhan bawang merah di tanah andisol lebih baik daripada di tanah inceptisol., Nutrients are an important factor in growth of shallot plants. One of the main nutrients that support the growth of shallots is potassium. The objective of this study was to find out the growth of shallots cultivated at various levels of potassium nutrients in andisol and inceptisol soils. The study was conducted at the Plastic House of Tajur Experimental Garden, PKHT IPB, South Bogor, Bogor, West Java, from February until September 2021. This study was designed according to randomized complete block design (RCBD), two factor. The factors are soil type (andisol and inceptisol) and potassium nutrient levels as treatments. The observed variables included plant height, number of leaves, number of tillers, average diameter, number of bulbs per clump, wet weight of plants, wet weight of bulbs, dry weight of plants, and dry weight of bulbs. Based on the results of the study, interaction between soil type and potassium nutrient had an effect on wet weight of plants, wet weight of bulbs, dry weight of plants, and dry weight of bulbs. The result of study also shown in general, the growth of shallot in andisol soil better than inceptisol soil.
Keyword: pottasium, allium ascalonicum, andisol, inceptisol

Judul: Consistency and Shrink-Swell Soils in Shallot Field, Brebes Regency, Central Java
Abstrak: Bawang merah merupakan salah satu komoditas yang sangat dibutuhkan dalam kehidupan sehari-hari. Sentra produsen bawang merah terbesar di Indonesia adalah Kabupaten Brebes. Namun pada kenyataannya produktivitas bawang merah di Kabupaten Brebes mengalami penurunan. Salah satu upaya untuk meningkatkan produktivitas bawang merah yaitu dengan melakukan pengolahan tanah yang baik, misalnya dengan mengkaji konsistensi tanah di lahan tersebut. Kemampuan mengembang dan mengerut tanah yang tinggi dapat beresiko terhadap pertumbuhan umbi bawang merah. Resiko tersebut dapat diminimalisir dengan cara memperhatikan nilai COLE (Coeficient Of Linear Extensibility) yang merupakan indikator dalam penetapan sifat mengembang dan mengerut tanah. Penelitian ini bertujuan menganalisis konsistensi dan nilai COLE serta kaitannya dengan sifat fisik dan kimia tanah pada lahan bawang merah di Kabupaten Brebes, Jawa Tengah. Hasil penelitian menunjukkan bahwa Konsistensi dan Nilai COLE tanah berbeda antar jenis tanah. Indeks plastisitas, jangka olah, dan nilai COLE memiliki korelasi terhadap kadar klei dan bahan organik. Ketiga jenis tanah memiliki Indeks plastisitas yang tinggi, jangka olah yang sempit, dan nilai COLE yang baik. Hal ini menunjukkan kualitas tanah pada lahan ini masih perlu diperbaiki untuk memperoleh kondisi yang lebih baik bagi pertumbuhan bawang merah., Shallots are one of the commodities needed in everyday life. The largest shallot producing center in Indonesia is Brebes Regency. But in reality, shallot productivity in Brebes Regency has decreased. One of the efforts to increase shallot productivity is by doing good tillage, for example by assessing the consistency of the soil. The high ability of soil to swell and shrink can be a risk to the growth of shallot bulbs. This risk can be minimized by paying attention to the COLE (Coeficient Of Linear Extensibility) value which is an indicator in determining the soil swelling and shrinking. This study aims to analyze the consistency and value of shrink-swell soil and its relation to the soil physical and chemical properties on shallot fields in Brebes Regency, Central Java. The results showed that soil consistency and shrink-swell value were different among soil types. Plasticity index, tillage period, and shrink-swell value have a correlation with clay and organic matter content. All three soil types have high plasticity index, narrow tillage period, and good shrink-swell value. This shows that the quality of the soil on this land still needs to be improved to obtain better conditions for the growth of shallots.
Keyword: gleisol, cambisol, mediteran, productivity

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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