Optimasi Dosis Pupuk Kalsium dan Magnesium pada Bibit Kelapa Sawit (Elaeis Guineensis Jacq.) di Pembibitan Utama

Oil palm is one of the important plantation crops in the plantation sector. Increased oil palm plantation area causes the need for the availability of oil palm seedlings in large quantities. Good quality oil palm seedlings were obtained through intensive maintenance especially fertilization. Fertilizers needed for the growth of oil palm seedlings include calcium and magnesium fertilizers. The objective of this experiment was to determine the optimum rates of calcium and magnesium fertilizer for oil palm seedling (Elaeis guineensis Jacq.). This experiment was conducted at Cikabayan Experimental Station, IPB Darmaga, Bogor, from December 2011 to November 2012. The experimental design used was factorial randomized block design with three replications. The first factor was Ca fertilizer rates i.e., 0, 5, 10, and 20 g CaCO3 plant-1. The second factor was Mg fertilizer rates, i.e., 0, 24, 48, and 96 g MgSO4 plant-1. The results showed that calcium affected stomatal density, whereas magnesium fertilizer affected morphological and physiological variables (stomatal density and chlorophyll content) of oil palm seedling. Based on the plant height and stem diameter, the recommended rate of magnesium fertilizer for 8 months oil palm seedlings in the main nursery was 58 g plant-1. This total rate should be applied at different amount every month from 1-8 month, at 2.0, 2.0, 8.0, 9.3, 8.8, 9.3, 9.4 and 9.3 g MgSO4 plants-1, respectively. The optimum rate of calcium fertilizer was not able to be determined in this research

Fisiologi Daya Adaptasi Kedelai (Glycine Max (L.) Merr.) Terhadap Cekaman Ph Rendah Dengan Al Tinggi

Two AI-tolerant genotypes (KB 44001 and Genjah Jepang) and two AI-sensitive genotypes of soybean (Kedelai Lumut and KB 46015) were subjected to Al concentration (1.50 mM Al with pH 4.0) in hydroculture for 3 weeks; the growth and their physiological responses were identified by measuring the changes of pH media, NO3ˉ /NH4+ uptake, ion absorption and organic acid content in the tissues. The result revealed that Al-tolerant genotypes soybean show a much better growth than the sensitive genotypes. Moreover, the tolerant genotypes showed the different responses to Al stress; they changed the pH media more significantly, accumulated less Al in the roots and accumulated more oxalate acid than the sensitive genotypes. Both the tolerant and sensitive genotypes had similar pattern n in N03ˉ /NH4+ uptake and other cation uptake. The results suggested that tolerance of soybean genotypes to Al toxicity is associated with their ability in the exclusion AI

Evaluasi Konsumsi Air Beberapa Genotipe Padi untuk Potensi Efisiensi Penggunaan Air

Water use efficient varieties in rice may have good opportunity in term of economic value and scarcity of water. This study was conducted to determine water consumption among rice genotypes that conventionally cultivated as low land (IR64, IPB97-F-15, Ciherang, Mentik Wangi, and Rokan hybrid), up land (Jatiluhur, Silugonggo), and amphibian type (Way Apo Buru, that could be planted both as lowland and up land). Rice seedlings at 14 days old were transplanted in a plastic container containing 83 kg of air dried soil, 1 plant per whole and 6 plants per container. The experiment was conducted in a vinyl house, using randomized complete block design with three replications. During rice growth, water table was maintained at 2 cm above soil surface, and water was added and recorded weekly. The results showed that varieties reveal production components and yield were different significantly. Water consumptions among varieties were significantly different, ranged from 15.93 L plant-1 for IR64 to 24.13 L plant-1 for Jatiluhur, or equal with 3,639 to 4,827 m3 ha-1. Jatiluhur was the most efficient variety in using water. This finding may guide us to explore benefit of water use efficient variety as sustainable option in water management of rice cultivation

FISIOLOGI DAYA ADAPTASI KEDELAI (Glycine max (L.) Merr.) TERHADAP CEKAMAN pH RENDAH DENGAN Al TINGGI

Two AI-tolerant genotypes (KB 44001 and Genjah Jepang) and two AI-sensitive genotypes of soybean (Kedelai Lumut and KB 46015) were subjected to Al concentration (1.50 mM Al with pH 4.0) in hydroculture for 3 weeks; the growth and their physiological responses were identified by measuring the changes of pH media, NO3ˉ /NH4+ uptake, ion absorption and organic acid content in the tissues. The result revealed that Al-tolerant genotypes soybean show a much better growth than the sensitive genotypes. Moreover, the tolerant genotypes showed the different responses to Al stress; they changed the pH media more significantly, accumulated less Al in the roots and accumulated more oxalate acid than the sensitive genotypes. Both the tolerant and sensitive genotypes had similar pattern n in N03ˉ /NH4+ uptake and other cation uptake. The results suggested that tolerance of soybean genotypes to Al toxicity is associated with their ability in the exclusion AI

Toleransi Tanaman Kedelai Terhadap Cekaman Air: Uji Lapang Beberapa Genotipe Toleran

The purpose of this field verification was to determine the stability of yield of several drought-tolerant soybean genotypes selected from green house evaluation. The plants were planted at Muneng, Probolinggo in dry season (June-September 1995) with and without irrigation. From 5 tolerant genotypes, Mlg 2999 and Mlg 3474 gave a good stability of tolerance as evidence by less significance of growth and grain yield reduction. The tolerant genotypes of Mlg 2805 and Mlg 2984 suffered from tremendous leaves and pods abcission, leading to low yield