Judul: Pola Respon Spektral Jagung pada Berbagai Perlakuan Pemupukan dan Kenampakannya pada Citra Drone RGB
Abstrak: Kondisi fisik tanaman jagung berkaitan erat dengan kandungan hara N dan dapat diidentifikasi dengan analisis laboratorium, spektroradiometer, atau citra drone. Penelitian ini bertujuan untuk mengindentifikasi, membandingkan karakteristik pola respon spektral, dan menduga kadar-N daun jagung pada berbagai perlakuan pemupukan dan fase pertumbuhan yang diperoleh dari pengukuran spektroradiometer dan drone. Pengamatan reflektan jagung dilakukan mulai umur 2 – 10 MST (minggu setelah tanam) menggunakan alat spektroradiometer. Selain itu, pengamatan kadar-N dilakukan pada tanaman umur 4 dan 8 MST. Citra drone diolah menjadi indeks ExR (Excess Red Vegetation) dan GRVI (Green Red Vegetation Index). Hasil penelitian menunjukkan bahwa karakteristik reflektan perlakuan pemupukan jagung mempunyai kesamaan pada panjang gelombang cahaya tampak. Perbedaan karakteristik reflektan pada berbagai perlakuan pemupukan terlihat jelas pada rentang red edge dan NIR. Nilai reflektan pada rentang red edge dan NIR terus meningkat sejalan dengan bertambahnya umur tanaman, nilai reflektan tertinggi berada pada umur 8 MST dan nilai reflektan mulai turun sesudahnya. Nilai reflektan pada gelombang merah, hijau, dan red-edge mempunyai hubungan yang baik dengan kadar-N, sedangkan hubungan gelombang NIR korelasi dengan kadar-N sangat rendah. Indeks ExR dan GRVI tidak menunjukkan karakteristik spektral yang berbeda pada berbagai perlakuan pemupukan., The physical condition of corn plants is closely related to the nutrient N content and can be identified by laboratory analysis, spectroradiometer, or drone imagery. This study aims to identify, compare the characteristics of the spectral response pattern, and estimate the N content of corn leaves at various fertilization treatments and growth phases obtained from spectroradiometer and drone measurements. Observation of the reflectance of corn plants was carried out from the age of 2-10 week after planting using a spectroradiometer. In addition, observations of N-levels were carried out on plants aged 4 and 8 Weeks After Planting. Drone images are processed into ExR (Excess Red Vegetation) and GRVI (Green Red Vegetation Index) indexes. The results showed that the reflectance characteristics of the maize fertilization treatment were similar in the visible light wavelength. The difference in reflectance characteristics in various fertilization treatments was clearly visible in the red edge and NIR ranges. The reflectance value in the red edge and NIR ranges continued to increase in line with the age of the plant, the highest reflectance value was at 8 Weeks After Planting and the reflectance value began to decline after that. The reflectance values in the red, green, and red-edge waves have a good relation with the N-level. In the NIR wave the relation with the N-level is very low, this is because the NIR wave does not need chlorophyll so that it is reflected back. The ExR index and the GRVI index did not show different spectral characteristics in various fertilization treatments.
Keyword: indeks RGB, pola spektral, spektroradiometer

Judul: Pola Respon Spektral Tanaman Pangan dan Kenampakannya pada Citra Drone Multispektral
Abstrak: Salah satu cara untuk memantau kondisi lahan adalah dengan melakukan identifikasi perkembangan tanaman melalui respon spektral menggunakan spektroradiometer, yaitu alat ukur cahaya yang mampu mengukur radiasi spektral pada rentang panjang gelombang yang dipancarkan dari suatu objek. Penelitian ini bertujuan untuk melakukan analisis pola respon spektral tiga varietas padi, ubi jalar dan bengkuang berbasis dari data spektroradiometer dan membandingkan karakteristik pola spektral hasil pengukuran spektroradiometer dan citra drone multispektral. Penelitian ini dilakukan di Desa Situ Gede, Kecamatan Bogor Barat, Kota Bogor. Respon spektral tanaman padi, ubi, dan bengkuang berbeda dan respon spektral setiap jenis tanaman juga berbeda pada panjang gelombang yang berbeda. Semakin bertambah umur tanaman maka nilai reflektan pada rentang inframerah akan meningkat. Nilai reflektan varietas Nawacita pada rentang inframerah memiliki nilai reflektan yang lebih tinggi dibanding dengan varietas Siliwangi dan Palmerah karena dipengaruhi oleh struktur internal daun, lebar kanopi, dan konsentrasi air. Hubungan antara nilai reflektan citra drone dengan nilai reflektan spektroradiometer untuk tanaman menunjukan rata-rata R² diatas 0,6, One of the ways to monitor land condition is identify plant growth through a spectral response using a spectroradiometer, a light measuring instrument capable of measuring spectral radiation in the wavelength range emitted from an object. This study aims to analyze the spectral response patterns of three varieties of rice, sweet potato and jicama based on spectroradiometer data and to compare the characteristics of the spectral pattern measured by the spectroradiometer and multispectral drone photos. This research was conducted in Situ Gede Village, West Bogor District, Bogor City. The spectral response on rice, sweet potato and jicama plants was different and the spectral response of each plant type was also different at different wavelengths. The older plants age, the reflectance value in the infrared range will increase. The reflectance value of the Nawacita variety in the infrared range has a higher reflectance value than the Siliwangi and Palmerah varieties because it is influenced by the internal structure of the leaves, the width of thecanopy, and the water concentration. The relationship of the reflectance value of the drone image with the spectroradiometer reflectance value for plants shows an average of R² above 0,6.
Keyword: multispectral drone, spectral pattern response, spectroradiometer

Judul: Hydrothermal Synthesis of Biphasic Calcium Posphate
Abstrak: Biphasio calsium phosphate (BCP), which was a mixture of hydroxypatite (HA) and tricalcium phosphate (TCP), was synthesized by hydrothermal method followed by sintering process. Hydroxyapatite was produced by using natural calcium source CaO from hen's eggshell and (NH4)2HPO4 as phosphate souce, other hydroxyapatite sample was produce by using synthetic calcium source Ca(OH) and H3PO4 as phosphate source.
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