The study aimed to determine the years of events El Nino and La Nina, analyze the effects of El Nino and La Nina events on water balance, and determine the available growing periods in Waeapo areas under various rainfall conditions. Climate data analysis was carried out with the following stages: a) generation of rainfall data; b) analysis of extreme rainfall of El Nino and La Nina; c) calculation of land water balance using the Thornthwaite-Mather method; and d) determination of available growing period under various rainfall conditions. The results showed that in the last 30 years in the Waeapo area, there were eight times of a phenomenon of extreme dry rainfall (El-Nino), with an average intensity of once every three years. The phenomenon of extreme wet rainfall (La-Nina) occurred six times with an average intensity of once every five years. Based on the calculation of land water balance, during El-Nino rainfall conditions, there was an annual groundwater deficit of 403 mm or 172% of normal conditions, whereas during La-Nina rainfall conditions there was a surplus of annual groundwater of 775 mm or 222% of normal conditions. When an El-Nino phenomenon occurred, the available growing period was only five months (January to May), and when the La-Nina phenomenon occurred, the growing period was available throughout the year (12 months). Keywords: El Nino, La Nina, land water balance, available growing period, Buru Island   ABSTRAK Penelitian bertujuan untuk menentukan tahun-tahun kejadian El Nino dan La Nina, menganalisis dampak kejadian El Nino dan La Nina terhadap neraca air lahan, dan menetapkan periode tumbuh tersedia di daerah Waeapo pada berbagai kondisi curah hujan. Analisis data iklim dilakukan dengan tahapan sebagai berikut: a) pembangkitan data curah hujan; b) analisis curah hujan ekstrim El Nino dan La Nina; c) perhitungan neraca air lahan menggunakan metode Thornthwaite-Mather; dan d) penentuan periode tumbuh tersedia pada berbagai kondisi curah hujan. Hasil penelitian menunjukkan bahwa dalam periode 30 tahun terakhir di Daerah Waeapo sudah terjadi fenomena curah hujan ekstrem kering (El Nino) sebanyak delapan kali, dengan intensitas rata-rata tiga tahun sekali. Dan fenomena curah hujan ekstrem basah (La Nina) terjadi sebanyak enam kali dengan intensitas rata-rata lima tahun sekali. Berdasarkan perhitungan neraca air lahan, pada kondisi curah hujan El Nino terjadi defisit air tanah tahunan sebesar 403 mm atau 172% dari kondisi normalnya, sebaliknya pada kondisi curah hujan La Nina terjadi surplus air tanah tahunan sebesar 775 mm atau 222% dari kondisi normalnya. Ketika terjadi fenomena El Nino periode tumbuh yang tersedia hanya lima bulan (Januari s.d Mei), dan ketika terjadi fenomena La-Nina periode tumbuh berlangsung sepanjang tahun (12 bulan). Kata kunci: El Nino, La Nina, neraca air lahan, periode tumbuh tersedia, Pulau Buru

El Nino is one of the global phenomena that has affected the climate system of Indonesia, including Ambon Island of Maluku. One of the direct impacts of the El Nino phenomenon is the decrease of water availability on agricultural land. This study aimed: i) to analyze the period of El-Nino extreme rainfall events in Ambon Island as well as the intensity and its frequency; and ii) to analyze the impact of El Nino events on the water balance of agricultural lands on Ambon Island. Sixty years of climatic data period 1959-2018 from Pattimura Meteorological Station and Karang Panjang Geophysics Station were used to analyze extreme rainfall conditions of El Nino, and to calculate the water balance of land using the methods of Thornthwaite and Mather (1957). The results showed that 16 times El Nino events occurred in Ambon between 1959 and 2018, with the frequency of 1-7 times per year or four times per year. The most extreme El Nino events that occurred in Ambon were in 1977Ambon were in , 1987Ambon were in and 1997. The results of land water balance calculation during the El-Nino events showed seven months water deficit (September to March) which is 62,6% higher than the normal conditions; meanwhile, the optimum soil moisture occurred four months (June to September) or seven months shorter than the normal conditions which were 11 months (March to January).

Climate change has an impact that includes extreme climate events such as El Nino. Experience in recent decades has shown that the El Nino climate anomaly has caused prolonged droughts. Peanut are susceptible to drought in part or all of its growth phases due to below-normal rainfall. This study aimed to describe the occurrence of extreme El-Nino rainfall on Kei Kecil Island, Maluku Province, and how much the El-Nino events affected the planting season and peanut production on Kei Kecil Island. This was carried out using the algebraic average technique for calculating the average (normal) rainfall and the FAO (1978) method for determining the growing season. The variables observed were rainfall data and peanut plant productivity data. Data were analyzed using simple regression analysis. The results of the study showed that the El Nino phenomenon generally took place in the period from April to November; mostly starting in April, May, June and September, October and November. Drought events on Kei Kecil Island did not always coincide with El Nino events, and El Nino events did not always cause drought or rainfall below normal. In 1993, 2003, 2007, and 2012 the amount of rainfall on Kei Kecil Island was below normal (<2,308 mm per year) but these years were not recorded as El Nino years. Whereas, 1994, 2009, 2014, and 2018 were recorded as El Nino years but did not cause drought or rainfall under normal conditions on Kei Kecil Island. During the last 30 years, this incident occurred 3 times, i.e. in 1991, 1997, and 2015. The results of the analysis of the growing season showed that the planting season on Kei Kecil Island under conditions of average (normal) rainfall lasted for 289 days or 9 months 16 days (November 1 to August 16). Meanwhile, the growing season when extreme El Nino rainfall occurred, lasted for 201 days or 6 months 20 days (November 1 to May 20). This indicated that when El Nino occurred on Kei Kecil Island, there was a shift in the growing season (ending sooner). The results of the regression analysis illustrated that the increase of the value of rainfall would increase the productivity of peanut crop. Keywords: El Nino phenomenon, growing season, peanut, productivity, rainfall   ABSTRAK Perubahan iklim berdampak di antaranya terhadap kejadian iklim ekstrim seperti El Nino. Pengalaman dalam beberapa dekade terakhir ini menunjukkan bahwa anomali iklim El Nino telah menyebabkan kekeringan berkepanjangan. Kacang tanah rentan oleh deraan kekeringan pada sebagian ataupun seluruh fase pertumbuhannya akibat curah hujan yang di bawah normal. Penelitian ini bertujuan untuk mempelajari kejadian curah hujan ekstrim El-Nino di Pulau Kei Kecil, Provinsi Maluku, dan seberapa besar kejadian El-Nino mempengaruhi musim tanam dan produksi kacang tanah di Pulau Kei Kecil. Ini dilaksanakan dengan menggunakan metode teknik rata-rata aljabar untuk perhitungan curah hujan rata-rata (normal) dan metode FAO (1978) untuk penentuan musim tanam. Variabel yang diamati adalah data curah hujan dan data produktifitas tanaman kacang tanah. Data dianalisis menggunakan analisis regresi sederhana. Hasil penelitian menunjukkan fenomena El Nino umumnya berlangsung dalam periode April hingga November; terbanyak mulai bulan April, Mei, Juni dan September, Oktober dan November. Kejadian kekeringan di Pulau Kei Kecil tidak selalu bersamaan dengan kejadian El Nino, dan kejadian El Nino tidak selalu menyebabkan kekeringan atau curah hujan di bawah normal. Pada tahun 1993, 2003, 2007, dan 2012 jumlah curah hujan di Pulau Kei Kecil berada pada kondisi di bawah normal (<2.308 mm per btahun) tetapi tahun-tahun tersebut tidak tercatat sebagai tahun-tahun El Nino. Sementara itu, tahun 1994, 2009, 2014, dan 2018 tercatat sebagai tahun-tahun El Nino tetapi tidak menyebabkan kekeringan atau curah hujan di bawah kondisi normalnya di Pulau Kei Kecil. Selama periode 30 tahun terakhir kejadian ini berlangsung selama 3 kali, yaitu pada tahun 1991, 1997, dan 2015. Hasil analisis musim tanam menunjukkan bahwa musim tanam di Pulau Kei Kecil pada kondisi curah hujan rata-rata (normal) berlangsung selama 289 hari (1 November sampai dengan 16 Agustus; 9 bulan 16 hari). Sedangkan musim tanam ketika curah hujan ekstrim El Nino berlangsung selama 201 hari (1 November sampai dengan 20 Mei). Hal ini mengindikasikan bahwa ketika El Nino berlangsung di Pulau Kei Kecil, akan terjadi pergeseran musim tanam (berakhir lebih cepat). Hasil analisis regresi menggambarkan bahwa penigkatan nilai curah hujan akan menigkatkan produktivitas tanaman kacang tanah. Kata kunci: curah hujan, fenomena El Nino, kacang tanah, musim tanam, produktivitas

<p>The current researches about livelihood strategy in small island are not comprehensively revealing the impact of climate change, especially rainfall, on livelihood strategy of household. The objective of this research is to analyze livelihood strategy as the form of adaptation to rainfall anomaly in Tomra Village, Leti District, Southwest Maluku Regency. Village sample is purposively selected, which is specified on villages that conduct farming and fishery activities simultaneously. Household sample is also determined purposively, which is resulting in 25 fisher households. Data are analyzed with qualitative analysis technique to understand the adaptation pattern of fisher household to rainfall anomaly. Moreover, rainfall anomaly is measured with <em>Oceanic Nino Index</em> (ONI) that takes source from the measurement of <em>Sea Surface Temperature</em> (SST). Result of research indicates that rainfall anomaly has disturbed fishing activity as fisher’s livelihood work. This situation is dealt by household by utilizing various livelihood strategies, which among others are intensifying livestock breeding, entering non-farm jobs (working as livestock breeding laborer), and starting off-farm business (being fish trader). Livestock breeding and copra are done by 56 percents households, and this activity contributes for 65.5 percents to the revenue of households. The next household revenue is contributed by coconut commodity (copra), crop (corn), jobs as fisher laborer, livestock breeding laborer, and fish trader.</p>

Climate information/data of a region plays an important role in agricultural development in the region, because by utilizing the knowledge of the relationship between crops and climate, forecasts can be made of planting time, harvest time, drought (water deficit), flood (water surplus), pest attack and disease, determining the appropriate type of crop, and so on. The purpose of this study was to assess the presence of soil water and to determine the growing season in the Saumlaki area based on two rainfall conditions. This study used monthly rainfall data for 30 years (1990-2019) as well as other climatic data, such as air temperature, air humidity, sunshine duration and wind speed for 15 years (2005-2019). Computing of the water balance was carried out using Thornthwaite-Mather Method, and determination of growing season using soil water in optimum condition. Based on the calculation of the land water balance in the rainfall conditions there was a 75% chance of being surpassed by the groundwater deficit in the Saumlaki area which lasted for 6 months (June- November), whereas the value increases by 183 mm or 45.52% compared to normal conditions, that was from 402 mm to 585 mm. On the other hand, the groundwater surplus lasted only a month (May) and tended to decrease by 686 mm or 97.03% compared to normal conditions, from 707 mm to 21 mm. The optimum soil water content for plants in rainfall conditions was 75% chance of lasting for 6 months (January-June); 2 months shorter than the normal 8 months (December-July). In conditions of 75% chance of rainfall, the growing season in the Saumlaki area lasted for 7 months (December-June); a month shorter than the growing season in normal rainfall conditions of 8 months (December-July). Keywords: growing season, land water balance, rainfall, Saumlaki area   ABSTRAK Informasi/data iklim suatu tempat berperan penting dalam pengembangan pertanian di wilayah tersebut, karena dengan memanfaatkan pengetahuan tentang hubungan antara tanaman dan iklim dapatlah dibuat prakiraan waktu tanam, waktu panen, kejadian kekeringan (defisit air), banjir (surplus air), serangan hama dan penyakit, penentuan jenis tanaman yang sesuai, dan sebagainya. Tujuan penelitian ini untuk menilai keberadaan air tanah dan menentukan musim tanam di Daerah Saumlaki pada dua kondisi curah hujan. Penelitian ini menggunakan data curah hujan bulanan selama 30 tahun (1990–2019) dan data iklim lainnya (suhu udara, kelembaban udara, lama penyinaran matahari kecepatan angin) selama 15 tahun (2005-2019). Perhitungan neraca air lahan menggunakan metode Thornthwaite-Mather, dan musim tanam ditentukan berdasarkan kondisi air tanah optimum. Berdasarkan perhitungan neraca air lahan pada kondisi curah hujan berpeluang 75% untuk dilampaui, defisit air tanah di daerah Saumlaki berlangsung selama selama 6 bulan (Juni-November) yaitu nilainya bertambah sebesar 183 mm (45,52%) dibandingkan kondisi normalnya, yaitu dari 402 mm menjadi 585 mm. Sebaliknya surplus air tanah berlangsung hanya sebulan (Mei) dan cenderung berkurang sebesar 686 mm (97,03%) dibandingkan kondisi normalnya, yaitu dari 707 mm menjadi 21 mm. Kadar air tanah yang optimum bagi tanaman pada kondisi curah hujan peluang 75% berlangsung selama 6 bulan (Januari-Juni); lebih pendek 2 bulan dibandingkan kondisi normalnya 8 bulan (Desember-Juli). Pada kondisi curah hujan peluang 75%, musim tanam di daerah Saumlaki berlangsung selama 7 bulan (Desember-Juni); sebulan lebih pendek dibandingkan musim tanam pada kondisi curah hujan normalnya 8 bulan (Desember-Juli). Kata kunci : curah hujan, daerah Saumlaki, musim tanam, neraca air lahan