Geophysics and Meteorology

About 60% of the nearly 40 x 106 t office produced in Indonesia are from the island of Java. However, the rice self-sufficiencythat has been attained and maintained since 1984 could be threatened by changing climate, and has been affected by the climate variability effects of the E1 Nifio/Southem Oscillation phenomenon. To aid policy makers and planners in formulating strategic policy options, the effects of recurring droughts and possible climate change on rice yields were studied using climate and crop models. Three models were used to simulate climate change: those of the Goddard Institute for Space Studies, Geophysical Fluid Dynamics Laboratory, and the United Kingdom Meteorological Office. Several climate scenarios were generated for Ngawi, in East Java, and Sukamandi, in West Java. These models indicate that doubling greenhouse gases would increase solar radiation by 1.2-2.1%, minimum and maximum temperatures by 7.6-16.8°C, and precipitation by 20.5-91.7%. The Goddard Institute for Space Studies transient climate change scenarios indicate that maximum and minimum temperatures would increase by 3.5 and 4.9%, respectively, in 2010, 6.9 and 9.8%, respectively, in 2030, and 11.1 and 15.7%, respectively, in 2050. The rainfall increase varies from 7.0% for West Java in 2010 to 8.7% for East Java in 2050. The Decision Support System for Agrotechnology Transfer crop model slightly under-predicts lowland rice yields of several experimental plots in three sites in Java and one site in Sumatra, but the results are almost equal to or a little higher than farm level yields. Nevertheless, the simulation outputs and experimental plots yields are closely related with a coefficient of determination value of 87%. Changes in climate inthe decades of 2010, 2030, and 2050 could drastically reduce rice yield: the rice yield is estimatedto decrease by about 1% annually in East Java and less in West Java. Currently, the rice yields in dry years are about one half those of normal years.

Apriyana Y, Sarvina Y, Dewi ER, Pramudia A. 2017. Farmer adaptation strategy in paddy field affected by climate variability in monsoon regions. Asian J Agric 1: 9-16. Adaptation of agriculture cultivation to climate variability and climate anomalies both in paddy field especially in monsoon regions is one of the strategies to minimize the impact of these two phenomena to reduce the economic loss, particularly for food security in Indonesia. The objectives of this study are: (i) to identify onset and cropping pattern in irrigated land, rainfed and dry land in affected area due to climate anomalies, (ii) to collect information on carrying capacity water resources and adaptation practices applied by farmers and, (iii) to identify strategies for farmers on irrigated land, rainfed and dry land in the region affected by climate variability. The desk work analysis and field survey were conducted in Serang District, Banten Province, Subang District, West Java Province and Pati District, Cen...

Rainfall zoning analysis with fuzzy clustering method has been performed at the centre of paddy area in the northern coast of Banten Province and West Java Province. Rainfall data recorded in the 1980-2006 period from 62 rainfall stations in the northern coast of Banten Province and from 75 rainfall stations at Karawang and Subang in the northern coast of West Java Province have been used in this analysis. For the first analysis a calculation of arithmetic mean values representing EI-Nino, La-Nina and Normal condition has been performed. Next, a fuzzy clustering analysis is applied to these mean values. The clustering analysis consists of two steps. First, a symmetric and reflective compatibility relation matrix describing a distance function between rainfall stations is calculated. Second, a fuzzy equivalency relationship i.e. a transitive approach of fuzzy compatibility matrices is determined. The results of analysis indicate a difference in the equivalency level among the stations under the EI-Nino, La-Nina and Normal conditions in the northern coast of Banten Province and West Java Province. Based on the 75°/o equivalency level, in the northern coast of Banten area can be grouped into four rainfall zones under EI-Nino condition, two zones under La-Nina condition and three zones under Normal condition. On the other hand, in the northern coast of West Java area can be grouped into three zones under EI-Nino condition, two zones under La-Nina condition, and four zones under Normal condition.

Padi, jagung, kedelai dan bawang merah merupakan komoditas pangan unggulan di Indonesia. Jagung dan bawang merah umumnya ditanam sesudah padi atau kedelai di lahan sawah tadah hujan sehingga rentan terhadap kekeringan. Oleh sebab itu informasi iklim khususnya curah hujan dan suhu sangat penting dalam menentukan waktu tanam dan kebutuhan air yang tepat bagi tananam. Tujuan penelitian adalah menentukan waktu tanam dan kebutuhan air tanaman padi, jagung, kedelai, dan bawang merah berdasarkan analisis neraca air tanaman, serta menyusun peta waktu tanam di dua provinsi sentra produksi pangan Indonesia yaitu Jawa Barat dan Nusa Tenggara Timur agar risiko penurunan produksi karena kekeringan dapat diturunkan. Berdasarkan hasil analisis neraca air tanaman di 16 wilayah, tanaman yang ditanam pada tanah bertekstur debu memiliki waktu tanam rata-rata 13 dasarian, relatif lebih panjang dari tanah bertekstur lempung, liat dan pasir dengan waktu tanam berturut-turut: 10, 9 dan 5 dasarian. Wilayah dengan tekstur tanah pasir memiliki periode waktu tanam relatif lebih pendek karena tanah ini tidak dapat menahan air lebih lama di dalam tanah yang menyebabkan cekaman air lebih cepat terjadi. Tanaman padi lebih rentan terhadap kekeringan jika dibandingkan dengan tiga tanaman lainnya sehingga risiko kehilangan hasil juga relatif lebih tinggi. Kebutuhkan irigasi tanaman padi pada periode tanam Mei-Agustus dapat mencapai 4,9 mm hari-1 di provinsi Nusa Tenggara Timur. Karakteristik curah hujan Jawa Barat memiliki bulan basah > 7 bulan sehingga memungkinkan waktu tanam lebih lama yaitu (pada tanah bertekstur) debu: 10-15 dasarian, lempung: 8-14 dasarian, liat: 8-13 dasarian dan pasir: 4-7 dasarian. Nusa Tenggara Timur dengan kondisi iklim lebih kering (bulan kering > 7 bulan) umumnya tidak direkomendasikan untuk menanam padi gogo dan disarankan untuk menanam jagung untuk menekan risiko kehilangan hasil.

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To cope with limited evapotranspiration data, recently, there are many evapotranspiration estimation methods have been developed. Those methods were generally developed in sub tropic region when climate is not similar with Indonesia and the methods may not be applied directly. Validation of several estimation methods including Blaney Criddle, Radiation, Penman, and Pan Evaporation have been done in Cikarawang (Bogor) and Ciledug (Tangerang). The average correction factor and correlation coefficient (r) were respectively 1.83 for Blaney Criddle method (r = 0.97); 1.90 for Radiation method (r=0.97); 1.10 for Penman method (r=0.96), and 1.81 for Pan Evaporation method (r=0.98). Penman is the best method with regard on the smallest correction factor especially for station with complete climatic data. Since all methods have correlation coefficient of more than 0.95, those methods can be used to estimate evapotranspiration based on the available climatic data. The present study used the P...

Penelitian difokuskan untuk mengungkapkan keterkaitan antara indikator anomali iklim (yaitu anomali suhu permukaan laut di Pasifik Ekuator (anomali SST) dan Indeks Osilasi Selatan (IOS) dengan curah hujan, luas panen, dan produksi padi di Pulau Jawa, serta untuk menyusun saran alternatif penanggulangan kerawanan ketersediaan air untuk pertanian yang spesifik lokasi sehubungan adanya anomali iklim. Lokasi penelitian mencakup 514 stasiun curah hujan tersebar di 26 kabupaten di enam wilayah sentra produksi padi, yaitu Banten, Pantura Jawa Barat, DAS Serayu, Pantura Jawa Tengah, Pantura Jawa Timur dan DAS Brantas.

Abstrak. Penetapan waktu tanam yang tepat merupakan salah satu penentu keberhasilan panen dan peningatan produktifitas tanaman pangan. Kearifan lokal dan cara konvensional yang digunakan untuk menerapkan pola tanam telah mengalami bias akibat pergeseran awal musim tanam. Untuk memandu penyuluh dalam menyesuaikan waktu dan pola tanam, Badan Penelitian dan Pengembangan Pertanian mengembangkan Sistem Kalender Tanam Terpadu untuk menjawab permasalahan mendasar terkait dengan pengamanan dan peningkatan produksi beras nasional menghadapi varibilitas dan perubahan iklim. Makalah ini bertujuan untuk memaparkan perkembangan sistem informasi kalender tanam terpadu berbasis web pada level kecamatan untuk seluruh Indonesia. Sistem ini dibangun dengan mengintegrasikan tiga sub-sistem, yaitu sub-sistem data, model dan pencarian, yang dapat diakses melalui alamat litbang.deptan.go.id. Informasi utama yang diperoleh dari sistem ini adalah estimasi awal waktu tanam tanaman padi untuk musim tanam yan...

Rainfall zoning analysis with fuzzy clustering method has been performed at the centre of paddy area in the northern coast of Banten Province and West Java Province. Rainfall data recorded in the 1980-2006 period from 62 rainfall stations in the northern coast of Banten Province and from 75 rainfall stations at Karawang and Subang in the northern coast of West Java Province have been used in this analysis. For the first analysis a calculation of arithmetic mean values representing EI-Nino, La-Nina and Normal condition has been performed. Next, a fuzzy clustering analysis is applied to these mean values. The clustering analysis consists of two steps. First, a symmetric and reflective compatibility relation matrix describing a distance function between rainfall stations is calculated. Second, a fuzzy equivalency relationship i.e. a transitive approach of fuzzy compatibility matrices is determined. The results of analysis indicate a difference in the equivalency level among the station...

Rainfall zoning analysis with fuzzy clustering method has been performed at the centre of paddy area in the northern coast of Banten Province and West Java Province. Rainfall data recorded in the 1980-2006 period from 62 rainfall stations in the northern coast of Banten Province and from 75 rainfall stations at Karawang and Subang in the northern coast of West Java Province have been used in this analysis. For the first analysis a calculation of arithmetic mean values representing EI-Nino, La-Nina and Normal condition has been performed. Next, a fuzzy clustering analysis is applied to these mean values. The clustering analysis consists of two steps. First, a symmetric and reflective compatibility relation matrix describing a distance function between rainfall stations is calculated. Second, a fuzzy equivalency relationship i.e. a transitive approach of fuzzy compatibility matrices is determined. The results of analysis indicate a difference in the equivalency level among the stations under the EI-Nino, La-Nina and Normal conditions in the northern coast of Banten Province and West Java Province. Based on the 75°/o equivalency level, in the northern coast of Banten area can be grouped into four rainfall zones under EI-Nino condition, two zones under La-Nina condition and three zones under Normal condition. On the other hand, in the northern coast of West Java area can be grouped into three zones under EI-Nino condition, two zones under La-Nina condition, and four zones under Normal condition.

Analysis of Drought Level to Reduce Risk of Food Crop Harvest Fails in Banten Province ABSTRACT . Climate is one of the most important factor to the success of the agriculture production. Climate variability such as season change, lack or excess of water, are sample examples of climate factors which limit agriculture production. Planning agriculture activities which involving climate factors as one of the consideration will reduce crops production failure. This research conducted to identified the potency of drought at Banten Province by consecutive dry days analysis at 5, 10, and 15 continuous days or more. The result showed that the potency of drought at northern Banten is higher compared to middle and southern Banten. This was showed by the high opportunities of DHK = 5, 10, and 15 continuous days or more, as big as 0,65, 0,46, and 0,28. The lowest potency of drought occur at southern Banten with opportunities of DHK≥ 5, 10, and 15 continuous days or more, each as big as 0,43, 0,...

Rainfall fluctuates with time and changes randomly, which unfavorable for most of the cropping, such as paddy. An early warning system is required to ensure a productive paddy cropping system. This paper describes the rainfall prediction modelling using a neural network analysis at paddy production centre area in the northern coast of Western Java and Banten. Rainfall data from Baros in the northern coast of Banten, Karawang, and Kasomalang Subang in the northern coast of West Java have been used for setting and validating the model. The model provides rainfall prediction for the next three months (Y=CHt+3), using the inputs data of the number of month (X1=t), the rainfall at the current month (X2=CHt), the rainfall atthe following month (X3=CHt+1), the rainfall at the following two months (X4=CHt+2), the southern ossilation index (SOI) at the current month (X5=SOIt) and the NINO-3,4 sea surface temperature anomaly at the current month (X6=AnoSSTt). Rainfall data recorded in the 199...

The vast territory of Indonesia and its position flanked by two oceans and two continents make the Indonesia's climate very dynamic and complex. On the other hand, climate variability and its change continue to occur and the impacts vary signifikan in agriculture sector. The pattern and tendency of climate variability can be detected through global indices such as Nino 3.4 sea surface temperature (SST) and its relationship to rainfall anomalies. Rainfall is one of the climate parameters that most plays a role in agriculture. The most obvious impact of climate change on the agricultural sector is the reduction in planting area and the decrease in production. Therefore, the Agriculture Sectorneeds to make adaptation efforts to reduce the risk due to climate change. This paper presents the results of the analysis of the relationship between Nino 3.4 SST anomalies with rainfall anomalies to determine the key regions of Indonesia's climate diversity.Key Areas were identified based on the correlation more than 0.5 and less than-0.5 significance less than 0.1 of the Niño 3.4 SST index with rainfall anomalies. The results of the analysis show that every condition in both El-Niño and La-Niñahas a different lag and global index where the correlation is strong and significant. Key areas have been identified in El-Niño and La-Niñacondition.These regions are areas that are significantly affected by climate variability and have an impact on rainfall anomalies which will ultimately affect the agricultural sector.

Growing periods can be determined using water balance analysis to decrease harvest risk in certain area. Generally, there are two types of land use for crop i.e. irrigated land and non-irrigated land. The experiment objectives was to determine growing periods of food crop in Banten Province. Modified method of Thornthwaite and Mather of bookkeeping system of water balance was used based on decades data. Water balance analysis of irrigated land showed that the area of Serang District had growing periods potencially of 140-170 days with growing periods starting from Dec2 till Jan1, but needed water supply from irrigation as amount 8.5-22.5 mm to grow rice twice a year or planted with other food crops after rice if no irrigation. Meanwhile, Tangerang District (Pakuhaji) and Pandeglang District (Pagelaran) had potency of 182-193 days of growing periods with starting on Sep3 at Pakuhaji and on Dec3 at Pagelaran. In these area rice could be planted twice a year without irrigation. Futher ...

Growing periods can be determined using water balance analysis to decrease harvest risk in certain area. Generally, there are two types of land use for crop i.e. irrigated land and non-irrigated land. The experiment objectives was to determine growing periods of food crop in Banten Province. Modified method of Thornthwaite and Mather of bookkeeping system of water balance was used based on decades data. Water balance analysis of irrigated land showed that the area of Serang District had growing periods potencially of 140-170 days with growing periods starting from Dec2 till Jan1, but needed water supply from irrigation as amount 8.5-22.5 mm to grow rice twice a year or planted with other food crops after rice if no irrigation. Meanwhile, Tangerang District (Pakuhaji) and Pandeglang District (Pagelaran) had potency of 182-193 days of growing periods with starting on Sep3 at Pakuhaji and on Dec3 at Pagelaran. In these area rice could be planted twice a year without irrigation. Futher ...

Growing periods can be determined using water balance analysis to decrease harvest risk in certain area. Generally, there are two types of land use for crop i.e. irrigated land and non-irrigated land. The experiment objectives was to determine growing periods of food crop in Banten Province. Modified method of Thornthwaite and Mather of bookkeeping system of water balance was used based on decades data. Water balance analysis of irrigated land showed that the area of Serang District had growing periods potencially of 140-170 days with growing periods starting from Dec2 till Jan1, but needed water supply from irrigation as amount 8.5-22.5 mm to grow rice twice a year or planted with other food crops after rice if no irrigation. Meanwhile, Tangerang District (Pakuhaji) and Pandeglang District (Pagelaran) had potency of 182-193 days of growing periods with starting on Sep3 at Pakuhaji and on Dec3 at Pagelaran. In these area rice could be planted twice a year without irrigation. Futher ...

Professor at Departement of Social Economics, Faculty of Agriculture, Hasanuddin University, Makassar Doctoral Program Students, and staff at the Planning Bureau of the Ministry of Agriculture Republic of Planning Bureau of the Ministry of Agriculture Republic of Indonesia, DKI Jakarta Doctoral Program Students, and Secretary of the Directorate General of Animal Husbandry of the Ministry of Agriculture Republic of Indonesia, DKI Jakarta Research Institute for Agricultural Technology, Indonesian Agricultural Research and Development Agency, Bogor Reserchers of Indonesian Center for Agricultural Socio-Economic and Policy Studies, Bogor Reserchers of Indonesian Center for Agroclimate and Hydrology Research, Bogor

The paper describes about rainfall zoning and rainfall prediction modeling and its use for rice availability and vulnerability analysis. The study used rainfall data from Station Baros (Banten region), Station Karawang and Station Kasomalang Subang (Northern Coastal of West-Java), and Station Tarogong (Garut). Fuzzy clustering methods, that was applied for rainfall zoning, used the representative data for El-Nino, La-Nina and normal means condition during 1980-2006 periods. Neural network analysis technique was applied for rainfall prediction modeling. Training set of the model based on the rainfall data of 1990-2002 periods, and validation model based on data of 2003-2006 periods. The model were used to predict the rainfall of 2007-2008 periods. The distibution of equivalence value between rainfall stations was very variative under El-Nino, La-Nina and Normal condition. On the certain of equivalence level it could be derivated some different rainfall zone under El-Nino, La-Nina and normal condition. Model training set could explain 88% of Baros rainfall variability, 89% of Karawang rainfall variability, and 72% of Kasomalang rainfall variability. At Baros, Karawang and Subang, rainfall was predicted to be increased on November 2007-February 2008 period, and to be decreased on the March-June 2008, and to be increased on July-November 2008. The rainfall decreasing on the March-June would carry a losses of rice production up to 25%. But, applying the well irrigation management and suitable growing periods could decrease and mitigate the decreasing of paddy production.