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VARIABILITY OF NORMALIZED DIFFERENCE VEGETATION INDICES IN SUMATRA AND ITS RELATION TO CLIMATE ANOMALIES(KERAGAMAN INDEKS VEGETASI DI SUMATERA DAN HUBUNGANNYA DENGAN ANOMALI IKLIM)
Get PDFIndeks vegetasi yang diperoleh dari data NOAA-AVHRR sudah umum digunakan sebagai indikator kehijauan dan kekeringan vegetasi. Kondisi iklim global dan regional diatas Sumatera mempengaruhi indeks vegetasi di Sumatera. Penelitian ini bertujuan mempelajari keragaman indeks vegetasi terutama di Sumatra dan hubungannya dengan El Nino - Southern Oscillation (ENSO) dan Indian Ocean Dipole Mode Event (DME). LAC NDVI periode 1996-2002 digunakan untuk menganalisa koefisien keragaman dan analisis korelasi kanonik. Keragaman NDVI yang tinggi ditemukan di pantai timur, bagian selatan dan bagian utara Sumatera, sedangkan di bagian barat dan tengah keragamannya rendah. Secara keseluruhan, keragaman NDVI selama monsun barat lebih tinggi daripada periode monsun timur. ENSO dan DME mempangaruhi indeks vegetasi di Sumatera pada lag 0,4,dan 5 bulan (nyata pada taraf 5%). Kontribusi terbesar diberikan oleh variable kanonik lag 1 (R2=70.1%), sisa 29,9 % disebabkan oleh keragaman factor-faktor lainnya. Kerana korelasi dan signifikansi dari parameter iklim secara statistik tinggi, maka dapat digunakan sebagai prediktor NDVI di Sumatera. Diantara 6 time lag , parameter dengan lag 6 bulan mempunyai keragaman yang tertinggi. Namun, uji beda nyata menunjukkan bahwz korelasi kanonik pada lag 0,4,dan 5 yang mempunyai beda nyta tertinggi (pada taraf 95%). Struktur korelasi kanonik untuk parameter iklim pada lag 0 dan 1 didominasi oleh SOI dan anomaly SST. Sedangkan korelasi pada lag 2,5, dan 6 didominasi oleh SOI, anomaly SST, dan DMI. Berdasarkan hasil analisis tersebut, kami menyimpulkan bahwa analisis korelasi kanonik merupakan metode yang optimum untuk memprediksi NDVI di Sumatera pada lag 5 bulan menggunakan SOI, SSTA, dan DMI sebagai prediktor. Hasil ini menunjukkan bahwa parameter iklim dapat digunakan untuk memprediksi NDVI 5 bulan ke depan dengan baik di Sumatera
INDEKS KECUKUPAN AIR UNTUK PENETAPAN WAKTU BERA KEDELAI DI JAWA TENGAH(WATER SUFFICIENCY INDICES TO DETERMINE FALLOW PERIODS OF SOYBEAN IN CENTRAL JAVA)
Get PDFClimate anomaly has impact on yield and productivity of soybean. An alternative to minimize its impact, it is important to determine period of fallow for soybean in dry land. Period of fallow was determined by using agroclimate analysis such as water satisfaction index (WSI). WSI required daily climate data, soil and agronomy parameter to calculte ETR/ETM fluctuation . Agroecology and soybean yield data were collected from October 2003 to February 2004 in Pondok Village, Ngadirejo Sub-District, Wonogiri District and in Pojok Village, Nogosari Sub-District, Boyolali District . Fallow period was analyzed using CWB-ETo, a daily water balance software developed by IAHRI based on FAO method. WSI was calculated for El-Nino and La-Nina years to determine planting period. The result showed that fallow period were different between locations due to soil and climate variability. The longest fallow period is Blora District from Januri III to October II. While the shortest fallow period are Semarang and Magelang
GLOBAL ANALYSIS OF THE RELATIONSHIP BETWEEN PRECIPITATION AND VEGETATION DYNAMICS DERIVED FROM NOAA/AVHRR-NDVI (ANALISIS GLOBAL DINAMIKA CURAH HUJAN DAN VEGETASI BERDASARKAN INDEKS VEGETASI NOAA/AVHRR)
Get PDFThe study of changes in global precipitation patterns is a key element in the ongoing research of climate change. There are also changes that occur over the land surface, such as in vegetation, which are associated with changes in precipitation. However, a better understanding of precipitation- vegetation relationships on various time and space scales is needed.There were many studies on relationship between rainfall to NDVI such as in East Africa1), Bostwana2), Sahel3), Amazon and Northeastern Brazil4), China5), and also in global scale6)7). From those studies, the relation of precipitation and NDVI is complex, such as reported by Kerr8) that its relationship was linear in Senegal, while by Lu5) the relationship was quadratic in China. Additionally, Milich and Weiss3) found that the relationship was inconsistent from the year to the year in Sahel, Africa.Hence, this paper attempts to explore the relationship between climate variables and the vegetation dynamic derived from NOOA/AVHRR-NDVI value, based on either spatial scale or point data. The authors also tried to investigate the possibility to study the global environmental change by using satellite data
PENDUGAAN DEFISIT AIR TANAMAN JARAK (RICINUS COMMUNIS L) BERDASARKAN MODEL SIMULASI DINAMIKA AIR TANAH(PREDICTION WATER DEFICIT OF CASTOR OIL (RICINUS COMMUNIS L) WITH DYNAMIC SOIL-WATER MODEL SIMULATION)
Get PDFConstruction dynamic model soil – water that describes relationships between crop growth and development and environmental factors (weather and soil) can be further developed to be employed as a decision support tool . The objectives of the research : (1) to know interaction of factor weather , soil, castor oil crop, (2) construction dynamic model soil – water , (3) monitoring water deficit factor at level of water irrigation. The research consisted field observation and construction model. The experimental results were used to determine quantitative relationships to obtain model parameters, calibration, and validation. This research was conducted in field experimental station of Balitpa Sukamandi, and it was arranged in split plot design with three replications. Two variety of castor oil as main plot design were : (1) ASB 81, (2) ASB 60. Three levels of water irrigation as sub plot design were : (1) No water irrigation, (2) ½ ETp, (3) 1 ETp. Field measurements included weather variables, soil, and crop. The t-test does not indicate significant difference between observed and predicted soil water content. The model is valid and reasonably well for predicting soil water content as long as castor growth . The dynamic model soil-water can be employed as a decision support tool in the management of castor oil plantations in Indonesia
PERTUMBUHAN DAN PRODUKSI PAPRIKA PADA BERBAGAI INTENSITAS RADIASI SURYA DI DATARAN RENDAH, BATAM(GROWTH AND PRODUCTION OF SWEET PEPPER CULTIVATED UNDER DIFFERENT SOLAR RADIATION INTENSITY AT LOWLAND REGION OF BATAM)
Get PDFAn experiment has been conducted in Batam Island to study the response of sweet pepper which cultivated at lowland of 20 m asl, during November 2001 to May 2002. Five varieties have been used namely, Bangkok, Gold Flame, New Zealand, Spartacus and Tropica. Plants cultivated using hydroponic system under plastic house with ultra violet protection. The radiation of 100% (control) and it reduce of 25% and 50% used as treatment in order to determine the microclimate favourable for growing pepper in lowland. The results shown that reducing radiation intensity has influenced significantly on vegetatif growth, except leaf area index. The plants were grown under 100% and 25% radiation intensity performed taller with more branches compare to the plants under 50%. Variety of Spartacus has grew tallest than others. Stem diameter of control plants performed bigger than other plants, while reducing radiation intensity has no effect significantly to leaf area index. Experiment also revealed that reducing radiation intensity has significant effect on number and weight of peppers per plant, and thickness of flesh, compare to control. In general, Gold flame has produced best quality than others varieties although it has less number of fruits compare to Tropica
EFISIENSI KONVERSI ENERGI SURYA PADA TANAMAN KENTANG (Solanum tuberosum L.) (RADIATION USE EFFICIENCY IN POTATO (Solanum Tuberosum L.)
Get PDFEfisiensi penggunaan radiasi surya adalah nilai konversi radiasi surya menjadi energi kimia melalui proses fotosintesis. Nilai ini menunjukkan persentase berapa banyak energi radiasi yang diserap tanaman mampu diubah menjadi energi dalam bentuk kimia (Lawlor, 1993). Produksi berat kering berbagai tanaman rata-rata sekitar 1,4 g berat kering per MJ radiasi surya yang diserap tanaman atau dengan kata lain mempunyai nilai Efisiensi Konversi Energi (EKE 2,5) %. Pada tanaman kentang, dengan intensitas 2 GJ m-2 selama masa pertumbuhan 120 hari umumnya diperoleh nilai EKE 1,3 % (Jones, 1992)Sampai dengan tahun 2000 perkembangan luas panen tanaman kentang di Indonesia mencapai 73.068 ha, dengan total produksi 977.349 ton, atau produksi rata-rata per hektar berkisar 13,4 ton (BPS, 2000). Di Jawa Timur, Basuki et al. (1993) melaporkan, produktifitas 10 varietas kentang pada nilai ILD 1,26 – 3,93, berkisar 11 - 27 ton per hektar. Produksi ini apabila ditinjau dari sisi penangkapan energi surya, efisiensinya sangat rendah, karena menurut Haeder dan Beringer (1983), pada kisaran ILD tersebut semestinya dapat dihasilkan umbi kentang sekitar 20 – 50 ton per hektar. Kecenderungan hasil yang rendah ini disebabkan praktek budidaya tanaman yang kurang benar sehingga memberikan nilai konversi energi surya yang sangat tidak efisien, misalnya penggunaan jarak tanam yang terlalu lebar, penanaman tanaman pada saat musim hujan dimana banyak awan yang menghalangi radiasi surya, penanaman tanaman pada dataran tinggi yang cenderung berkabut, saat tanam tanpa memperhatikan fase pertumbuhan yang peka terhadap intensitas radiasi surya, dan lainnya. Untuk meningkatkan efisiensi penggunaan radiasi surya, berbagai cara dapat dilakukan. Sugito (1999) menyarankan beberapa cara perbaikan budidaya tanaman, diantaranya dengan mengurangi energi surya yang lolos pada pertanaman dan mengoptimalkan penggunaan energi surya yang jatuh pada kanopi tanaman, diantaranya dengan meningkatkan populasi tanaman. Haeder dan Beringer (1983) menambahkan peningkatan EKE dapat juga dilakukan dengan memilih kultivar yang berumur panjang dan pemilihan lokasi bersuhu 10 – 20 C dengan intensitas cahaya tinggi. Percobaan ini bertujuan untuk menganalisis peningkatkan efisiensi energi surya melalui pengaturan saat tanam, populasi tanaman serta penggunaan varietas yang potensial
ANALISIS KORELASI DEBIT AIR MASUK MUSIM KEMARAU PADA WADUK SERI DAS CITARUM DENGAN PERUBAHAN SUHU PERMUKAAN LAUT GLOBALCORRELATION ANALYSIS OF CITARUM DAMS INFLOWS AND GLOBAL SEA SURFACE TEMPERATURE IN DRY SEASON
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PREDIKSI NERACA AIR DENGAN KOMPUTER MODEL UNTUK ANTISIPASI BAHAYA KEKERINGANSOIL WATER BALANCE PREDICTON USING COMPUTER MODEL TO ANTICIPATE DROUGHT
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PENGGUNAAN INDEKS OSILASI SELATAN UNTUK MEMPRAKIRAKAN SIFAT HUJAN MUSIMAN GUNA MENENTUKAN STRATEGI TANAMAN DI LAHAN TADAH HUJAN DI PULAU LOMBOK SHOUTHERN OSCILLATION INDEX FOR FORCASTING SEOSONAL RAINFALL CHARACTERISTIC TO DETERMINE UPLAND ...
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PENYUSUNAN MODEL SIMULASI TANAMAN JARAK (Richinus communis L.)CONSTRUCTION OF A CROP SIMULATION MODEL OF CASTOR OIL (Richinus communis L.)
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