Judul: Pengaruh Aplikasi Hidrogel dan Interval Penyiraman terhadap Pertumbuhan Terong (Solanum melongena) pada Media Tanam Pasir Kuarsa.
Abstrak: Sebaran tanah berpasir di Indonesia cukup luas terutama di Kalimantan Tengah dan area-area bekas tambang timah di pulau Bangka dan pulau Belitung. Tanah berpasir memiliki kapasitas menahan air yang rendah karena teksturnya yang kasar. Aplikasi bahan pembenah tanah, seperti bahan organik dan hidrogel, menjadi salah satu upaya untuk meningkatkan daya ikat air pada tanah berpasir. Hidrogel adalah bahan pembenah tanah bersifat hidrofilik dengan kapasitas menahan air yang tinggi. Penelitian ini bertujuan mengkaji pengaruh aplikasi hidrogel dan interval penyiraman terhadap ketersediaan air, sifat kimia tanah dan pertumbuhan terong pada media tanam pasir kuarsa. Penelitian dilakukan di rumah kaca Kebun Pendidikan Cikabayan menggunakan polybag berisi 5 kg pasir. Rancangan penelitian menggunakan Rancangan Acak Lengkap (RAL) dua faktor, yang terdiri dari dosis hidrogel (H) 4 taraf: 0, 10, 20, 40 g, dan interval penyiraman pada media tanam (P) terdiri dari 3 taraf: Penyiraman 5 hari sekali, penyiraman 10 hari sekali, penyiraman 15 hari sekali. Hidrogel dan pupuk dasar NPK dicampurkan dengan media tanam. Parameter yang diamati adalah kandungan unsur hara pasir kuarsa, tinggi tanaman, jumlah daun, bobot basah dan bobot kering tanaman. Aplikasi hidrogel secara nyata mampu meningkatkan tinggi tanaman, jumlah daun, bobot basah dan bobot kering pada tanaman terong, serta meningkatkan K-dd dan kadar air dalam pasir kuarsa setelah panen. Namun, aplikasi hidrogel tidak mempengaruhi kandungan unsur hara seperti P tersedia, N total, Na-dd, Ca-dd, KTK, C-organik, dan Mg-dd. Perlakuan optimal untuk pertumbuhan terong terdapat pada kombinasi hidrogel 40 g dengan interval penyiraman setiap 5 hari sekali.
Keyword: drainage, hydrogel, intervals, hydrophilic polymers, quarzt sand

Judul: The Effect of Hydrogel Application and Watering Interval on Growth of Sengon (Paraserianthes falcataria) on Quartz Sand Planting Media
Abstrak: Media tanam yang tersusun dari pasir-pasir kuarsa mempunyai struktur lepas, tidak mampu menahan air, serta mudah terjadi pencucian hara, sehingga diperlukan bahan pembenah tanah untuk memperbaikinya, misalnya dengan menggunakan hidrogel. Penelitian ini bertujuan mengetahui pengaruh dosis hidrogel dan interval penyiraman terhadap pertumbuhan tanaman, serta sifat-sifat kimia tanah. Sengon digunakan sebagai tanaman indikator untuk mengetahui pengaruh hidrogel. Metode yang digunakan adalah rancangan acak lengkap dengan dua faktor perlakuan. Faktor pertama adalah empat taraf dosis hidrogel, yaitu tanpa hidrogel, 10 g hidrogel/5 kg media tanam, 20 g hidrogel/5 kg media tanam, dan 40 g hidrogel/5 kg media tanam. Faktor kedua adalah perlakuan interval penyiraman dengan tiga taraf, yaitu penyiraman dengan interval setiap 5 hari, 10 hari, dan 15 hari. Pengamatan dilakukan terhadap tinggi, jumlah daun, bobot basah dan kering tanaman serta analisis sifat kimia tanah. Hasil percobaan menunjukkan bahwa aplikasi hidrogel secara nyata mampu meningkatkan tinggi, jumlah daun, dan bobot basah serta bobot kering tanaman Sengon, tetapi tidak berpengaruh terhadap sifat kimia tanah. Perlakuan interval penyiraman tidak berpengaruh terhadap kandungan hara pasir kuarsa. Dosis terbaik diperoleh pada 20 dan 40 g hidrogel/5 kg pasir kuarsa dengan interval penyiraman masing-masing 5 dan 10 hari sekali., Planting media composed of quartz sands has a loose structure, unable to hold water, and susceptible to nutrient leaching, therefore a soil conditioner is needed to improve it, such as using hydrogel. This study aims to determine the effect of hydrogel dose and watering interval on plant grow and soil chemical properties. Sengon was used as an indicator plant to determine the effect of hydrogel application. The experiment was designed using a completely randomized design with two treatment factors. The first factor was four levels of hydrogel dose, specifically without hydrogel, 10 g/5 kg of planting media, 20 g/5 kg of planting media, and 40 g/5 kg of planting media. The second factor was the treatment of watering period interval which consisted of once in 5 days of watering, once in 10 days of watering, and once in 15 days of watering. Variables observed consist of plant height, number of leaves, fresh and dry weight of the plant and soil chemical analysis. The results showed that the application of hydrogel significantly increased the height, number of leaves, and fresh and dry weight of Sengon plants, but did not affect the chemical properties of the soil. The watering interval treatment did not affect the nutrient content of quartz sand. The best dose of hydrogel application was 20 and 40 g hydrogel/5 kg of quartz sand with watering intervals of 5 and 10 days.
Keyword: Hidrogel, Interval penyiraman, Pasir kuarsa, Sengon

Judul: Categorization in Macaca fascicularis.
Abstrak: Categorization is an ability to group individuals or events into different classes mediated by conceptualized mental images. There are several levels of categorization and within a taxonomy the levels are nested. At the most concrete level of categorization, all or most members of the category shared common physical attributes that differ from other categories. The higher the level of category, the fewer common attributes between members of the group. In addition to humans, the ability to categorize has also been proposed in animals. One example of categorization in animal is species discrimination. Using matching-tosample task, present experiment tested ability of the long-tailed macaque (Macaca fascicularis) in discriminating dichotomous-stimuli of different animals. The species has been shown to be able to see photos as representations of real object so I used facial photos of humans and animals for the stimuli. First, I tested their ability to classify humans and macaques into separate group. Second, I tested their ability to discriminate their conspecific from other macaques. And the last, I tested whether the subjects were able to discriminate non-human animals from humans. In all of these experiments I found that the subjects showed high performance in categorizing objects, even when I discarded details of visual informations, such as color and local shapes. The ability to identify objects with reduced representation of physical properties means the subjects were able to generalize attributes of members of the group. This would indicate that the subjects created a higher level abstraction. On the other hand, in discriminating intrageneric macaque species I found that they were able to extract uniqueness of each species. More over, I also found that the subjects were able to put photos of non-human animals that shared very few similarities in physical percepts into one group. I suggested that the subjects could create a more abstract concept based on non-percepts relations as a basis to put the objects into one category. Thus, I concluded that M. fascicularis were able to perform multiple levels of categorizations.
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