Judul: Water use efficiency on upland sugar cane
Abstrak: Low Indonesian sugar production is mainly due to low productivity and low sugar yield. The shift of sugarcane crop acreage from low land to upland was the major factor of low productivity. Cultivation of sugarcane in uplands faced many constraints, namely low availaibility of soil water, low soil nutrient and unavailability of appropriate varieties. Cane cultivation in upland is commonly done at the beginning of the wet season (in November) in order to avoid the plant from water stress at the beginning of growth period. This causes the sugarcane age of only 7 months and have not reach maturity at harvest time in June which leads to lower sugarcane productivity. Shifting planting season is an alternative that can be done to obtain plants with sufficient maturity at the harvest time. However, the consequences of shifting the planting season is that the planting occured on dry season and which means that watering is needed. The limited availability of water demands efficiency in water usage. The application of organic matter as filter cake compost is expected to reduce the frequency of irrigation. This aims of this study are (1) to study the effect of water supply on performance of several varieties of sugarcane, (2) to study the effect of filter cake compost on nutrient uptake by sugarcane at various irrigation levels, (3) to analyze the efficiency of water usage in connection with the provision of filter cake compost in some varieties of sugarcane, and (4) to develop recommendation of water supply efficiency in the field with the addition of filter cake compost. The study was conducted in three stages of the experiment, which were the performance of several varieties under water stress, the effect of filter cake compost and irrigation on plant nutrient uptake, and the application of filter cake compost and frequency of irrigation on upland sugar cane productivity. The sugarcane varieties used in the experiments of performance varieties under different moisture content were PS 851, PS 864, PS 862, PS 921, PS 951, PS 91-787 and BL. After 3 months observation, it appears that water stress began significantly affected plant growth at 50% of field capacity (FC). The results showed that seven varieties were able to grow well under soil water content up to 75% FC. Based on Drought Tolerance Index, varieties BL and PS 864 has DTI values close to tolerant, while others were considered as moderate tolerant. Although the DTI value of PS 921 was only classified as moderately tolerant, it has the highest biomass in all of the soil water content treatments. It shows that PS 921 has the highest potential among the other varieties as variety of sugarcane suitable for upland planting. To study the effect of filter cake compost and water supply on the nutrient uptake of sugarcane, the variety PS 921 was used. The dose of filter cake compost were 0, 5, 10, 15, and 20 tons per hectare and the soil water content were 100%, 75% and 50% FC, respectively. The results of this experiments show that the uptake of P by sugarcane was influenced
Keyword: Water use efficiency, Saccharum officinarum L., Saccharrum robustum L.

Judul: Studi Karakter Morfologi dan Fisiologi yang Berkaitan dengan Efisiensi Pemakaian Air Varietas Padi Gogo
Abstrak: The demand for food consumption of rice increased with the increasing population, while recently wetland experiencing a great reduction. Therefore, dry land cultivation has been developed, including cultivation of upland rice. Dry land crop management in general is constrained by the availability of water, because source of water are only the rain and the soil's ability to retain water. Upland rice cultivation required specific cultivation, particularly the use of crop varieties that have good water-use efficiency or varieties of plants that are able to adapt to the conditions of limited water availability. Research on morphological and physiological studies related to water use efficiency of upland rice varieties need to be developed in order to create optimum utilization of dry land. The research was conducted from October 2013 to April 2014 in the greenhouse IPB Experimental Station Cikabayan, Bogor. The research design was arranged in factorial experiment and using a randomized block design. The first factor was 5 upland rice varieties (Inpago 5, Batutegi, Jatiluhur, Inpago 8 and Sarinah). The second factor was 4 irrigation intervals which were 3, 6, 9, and 12 days. Thus there are 20 combinations of treatment. Each treatment was repeated 3 times and each experimental unit consisted of 3 media so that overall there are 180 growing media. Each planting medium consisted of three plant sample (one family). Plants in polythene bags are used as destructive plants, and were observed at the time of entry phase of the vegetatife phase and the generative phase based on the characteristics of each variety. Plants in buckets are used for the measurement of growth until the generative phase. Characteristics that assosiated with water saving of upland rices were higher plant height, longer panicle, larger roots volume, narrower leaves, higher evapotranspiration, faster flowering phase, greener leaves, higher number of leaves and tillers, heavier dry matter, higher number of grains, heavier 100 grain weight and dry weight of grains. The fraction of available absorbed water at panicle inisiation, flowering inisiation and harvesting phase was 83.36%, 137.14% and 116.65%, respectively, to obtain dry grains of 3.39 ton ha-1. Productivity of each variety at intervals of 3 days irrigation was 3.80 ton ha-1 (Inpago 5), 3.27 ton ha-1 (Batutegi), 3.86 ton ha-1 (Jatiluhur), 3.91 ton ha-1 (Inpago 8) and 2.12 ton ha-1 (Sarinah).
Keyword: Batutegi, evapotranspiration, productivity, water fraction

Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix