A field study on peat soil to investigate impacts of soil water table depth and soil ameliorant (steel sludge) had been carried out on mature oil palm. Three treatments of soil water table management and four rates of steel sludge application were applied in this study. Treatments of soil water table management were WLM1, WLM-2, and WLM-3, where soil water table depth was maintained at 35-50 cm, 60-75 cm, and >75 cm below the soil surface, respectively. Treatments of steel sludge were application of this soil ameliorant at the rate of 0; 3.15; 6.51; 9.86 kg tree-1. The study was arranged as split plot randomized block design by assigning soil water table management as main plot and rate of steel sludge as sub plot. Soil Data observed were actual soil water content, peat soil properties, CO2 emission, vegetative growth, and palm yield. The results showed that maintaining soil water table depth at < 75 cm could maintain actual soil moisture up to top parts of peat soil. On the other hand, deeper soil water table (>75 cm, WLM-3) caused significant effects on decreasing of soil moisture in the 0-10 cm layer of peat soil. CO2 emission was 37, 40, dan 45 ton ha-1 year-1 under WLM-1, WLM-2, and WLM-3, respectively. The drop of soil water table to >75 cm (WLM-3) significantly increased CO2 emission to about 11-18% higher than that on WLM-1 and WLM-2. Steel sludge application did not significantly decrease CO2 emission. The highest FFB yield was observed under WLM-1, then followed by WLM-2 and WLM-3. FFB yield was significantly higher when soil water depth was maintained at 35-75 cm than that at > 75 cm, it was 7-10% and 36-60% higher in 2014 and 2015, respectively. There were no significant effects of steel sludge application on FFB yield, but there was improvement on average bunch weight.
The effectiveness of fertilization, could be influenced by the type of fertilizer and the right method. There are several methods of fertilization, such as fertilizer aplied in pockets and scattered. Relations fertilization method with root distribution of oil palm plantations and nutrients in the soil need to be known, so it can be determined in a more effective method of fertilization for oil palm plantations. The observation was performed 1 year after application, includes observation of the soil (physical and chemical properties) and the observation of the root (primary root, secondary, tertiary). Examples of soil and roots were taken at depths of 00-20 cm, 20-40 cm, 40-60 cm, 60-80 cm, and 80-100 cm at a distance of 50 cm, 100 cm, 150 cm, 200 cm, 250 cm, 300 cm, 350 cm, 400 cm from the base of the stem. The results showed that the distribution of nutrients in the soil surface is greater than the layer underneath and root production decreased due to lower soil layers. ABSTRAKEfektifitas pemupukan, salah satunya dapat di pengaruhi oleh jenis pupuk dan metode yang tepat. Ada beberapa metode pemupukan, antara lain pupuk sebar dan pupuk pocket. Hubungan metode pemupukan dengan distribusi akar tanaman kelapa sawit dan hara dalam tanah perlu diketahui, sehingga dapat ditentukan metode pemupukan yang lebih efektif untuk perkebunan kelapa sawit. Pengamatan dilakukan 1 tahun setelah aplikasi, meliputi pengamatan tanah (sifat fisik dan kimia) dan pengamatan akar (akar primer, sekunder, tersier). Contoh tanah dan akar diambil pada kedalaman 0 -20 cm, 20 -40 cm, 40 -60 cm, 60 -80 cm, dan 80 -100 cm pada jarak 50 cm, 100 cm, 150 cm, 200 cm, 250 cm, 300 cm, 350 cm, 400 cm dari pangkal batang. Hasil penelitian menunjukkan bahwa sebaran hara pada permukaan tanah lebih besar dibandingkan dengan lapisan bawahnya dan produksi akar semakin menurun seiring dengan penurunan lapisan tanah.
Ganoderma boninense is a major devastating disease for oil palm. The severity level identification of Ganoderma boninense on oil palm plantation is important to support the decision making on managerial activities. There have been researches conducted about the usage of unmanned aerial photograph (UAV) on oil palm plantation, nonetheless, the utilization of digital data on the visible aerial photograph has not optimally used. This study aims to obtain alternative methods to identify the severity level of Ganoderma boninense infection with visible spectral index from a visible aerial photograph (RGB). Visible aerial photograph (RGB-aerial photograph) is adopted on this research and carried out at Dusun Ulu plantation with various visible spectral-index methods. The visible spectral-index methods are the excess green index (ExG), the excess red index (ExR), the excess green minus excess red index, and the colour of vegetation extraction (CIVE). The results of four visible spectral-index methods are able to differentiate the severity level of Ganoderma boninense infection on each individual of oil palm.
The purpose of this study is to examine the effectiveness of four monetary policy transmission channels, i.e. direct monetary, interest rate, credit, and exchange rate, on inflation rate in Indonesia as the single target, and to determine the most suitable variables for operational target on the most effective channel. The quantitative research method applied in this study used Vector Auto Regression (VAR) model to analyze the effectiveness of monetary policy transmission channels in Indonesia in the period from the first quarter of 2000 to the third quater of 2013. The data were taken from Indonesia Finance Statistics (SEKI), Bank Indonesia Annual Reports, IMF Finance Statistics, and Publication of the Central Bureau Statistics. The results show that the interest rate channel is the most effective method compared with the other channels. The analysis done through testing impulse response and variance decomposition tests indicates the reliability of interest rate channel in reaching the inflation target. The interest rate of the interbank money market is the most suitable indicator for operational target of the interest rate channel. Test results using path impluse response method indicates that shocks of RPUAB get a strong and fast response. Abstrak Tujuan Penelitian ini untuk mengetahui di antara keempat jalur transmisi kebijakan moneter, yaitu jalur moneter langsung, jalur suku bunga, jalur kredit, dan jalur nilai tukar yang lebih efektif dalam implementasi kebijakan moneter dengan sasaran tunggal inflasi di Indonesia dan mengetahui variabel yang paling cocok digunakan sebagai sasaran operasional pada jalur yang paling efektif. Metode penelitian yang digunakan adalah penelitian kuantitatif dengan menggunakan analisis Vector Autoregression (VAR). Penelitian ini merupakan studi kasus untuk Indonesia periode tahun 2000 triwulan I sampai dengan tahun 2013 triwulan III. Data bersumber dari Statistik Ekonomi dan Keuangan Indonesia (SEKI), Laporan Tahunan Bank Indonesia, IMF Finance Statistics, dan publikasi Badan Pusat Statistik. Hasil penelitian menunjukkan bahwa jalur suku bunga merupakan jalur yang paling efektif dibanding dengan jalur-jalur lainnya. Analisis yang dilakukan melalui uji impulse response dan uji variance decomposition menggambarkan keandalan penggunaan jalur suku bunga dalam mencapai sasaran akhir inflasi, terlihat dari respon yang diberikan oleh inflasi dan varians dari variabel-variabel yang terlibat dalam jalur ini. Pengujian pada jalur suku bunga menunjukkan bahwa shock RPUAB mendapatkan respon yang kuat dan juga cepat dari inflasi sehingga cocok digunakan sebagai sasaran operasional dalam mencapai sasaran akhir inflasi.
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