ANALISIS DAMPAK KERAGAMAN CURAH HUJAN TERHADAP KINERJA PRODUKSI PADI SAWAH (Studi kasus di Kabupaten Merauke, Papua) - Rouw, Aser (Jurnal Pengkajian dan Pengembangan Teknologi Pertanian, 2008)
Analyzing of Rainfall Variability Impact toward Rice Field Production (Case study at Merauke Papua). This study was conducted with aim: (1) knowing impact of rainfall variability to rice field production and (2) to arrange alternative planting strategy which can decrease rainfall variability impact. Analyzing approach used Decision Support System for Agro-Technology Transfer (DSSAT) Plant Simulation Model. Input of model consists of time series climate data for twenty years (1983-2003), soil physics and chemist data, IR 64 variety genetics data, and the farmers planting technology. The rice field production was simulated following time planting in 15 days. To know pattern of rice field production, output of analysis was plotted using Fourier regression. The result of simulation showed that the rice filed production followed rainfall variability event. The higher production 5, 4 t with lower variance ± 0,1 at the first planting season was gotten in December 15th. While the second planting season, the higher production just 3, 2 t with variance ± 0,3 was gotten in 15 July th. This case was caused by lower of rainfall event. If, the total of the farmers irrigation supply was increased from 630 mm to 850 mm, so average production on first planting season become 5,9 t and second planting season 6 t. If the farmer just used rainfall event, so the best time planting was in November with production was 6 t and variance ± 1,1. Key words: Variability, rainfall, production, rice field, simulation. Analisis dampak keragaman curah hujan terhadap kinerja produksi padi sawah: Kasus Kabupaten Merauke, Papua dilakukan dengan tujuan: (1) mengetahui seberapa besar dampak keragaman curah hujan terhadap produksi padi sawah, dan (2) menyusun alternatif strategi budidaya padi sawah yang dapat mengurangi risiko keragaman curah hujan. Pendekatan analisis menggunakan model simulasi tanaman DSSAT (Decision Support System for Agro-technology Transfer). Data input model terdiri atas seri data iklim harian 20 tahun (1983-2003), data fisika dan kimia tanah, dan data genetik varietas padi IR 64, serta data telcnologi budidaya padi sawah. Simulasi produksi padi sawah dilakukan menurut waktu tanam dalam selang 15 harian. Output analisis diploting menggunakan regresi Fourier. Hasil simulasi menunjukkan bahwa keragaman produksi padi sawah cenderung mengikuti pola keragaman curah hujan. Rata-rata produksi -tertinggi 5,4 t dengan keragaman terendah ± 0,1 pada MT I tercapai pada waktu tanam 15 Desember. Sedangkan MT2 rata-rata produksi tertinggi hanya mencapai 3,2 t dengan keragaman ± 0,3 tercapai pada tanggal tanam 15 Juli. Hal ini disebabkan karena rendahnya input curah hujan. Hasil ini masih dapat ditingkatkan, yaitu melalui penambahan suplai air irigasi petani clari 630 mm menjadi 850 mm, maka rata-rata produksi MT] mencapai 5,9 t dan MT2 6 t. Kalau hanya mengandalkan curah hujan, maka waktu tanam terbaik bagi petani adalah pada tanggal tanam 1 November, yaitu rata-rata produksi dapat mencapai 6 t dengan keragaman f 1,1. Kata kunci: Keragaman, curah hujan, produksi, padi sawah, simulasi