ABSTRAK
Dampak perubahan iklim sangat dirasakan sektor pertanian, khususnya pertanian lahan tadah hujan. Ketersediaan air pada pertanian lahan tadah hujan sangat ditentukan oleh kondisi curah hujan. Perubahan iklim menyebabkan kesenjangan antara ketersediaan air dengan kebutuhan air. Penelitian bertujuan untuk mengetahui kondisi perubahan iklim, bentuk adaptasi, faktor-faktor yang mempengaruhi adaptasi, dan merumuskan strategi adaptasi petani lahan tadah hujan terhadap perubahan iklim dalam memenuhi kebutuhan air tanaman di Desa Ngaglik Kecamatan Gebang dan Desa Harjobinangun Kecamatan Grabag Kabupaten Purworejo. Metode yang digunakan dalam penelitian ini adalah deskriptif kuantitatif. Data dikumpulkan melalui wawancara terstruktur dan observasi. Analisis data dilakukan dengan analisis deskriptif dan regresi logistik.
Hasil penelitian menunjukkan bahwa: 1) Iklim di Desa Ngaglik Kecamatan Gebang dan Desa Harjobinangun Kecamatan Grabag telah mengalami perubahan berupa pergeseran puncak musim hujan, puncak musim kemarau, awal bulan basah bulan lembab dan bulan kering serta tipe iklim; 2) Bentuk adaptasi petani lahan tadah hujan terhadap perubahan iklim dalam memenuhi kebutuhan air tanaman di Desa Ngaglik Kecamatan Gebang dan Desa Harjobinangun Kecamatan Grabag adalah praktik konservasi lahan, irigasi suplementer, dan panen air. 3) Ketersediaan sumber air berpengaruh signifikan pada taraf nyata 5% terhadap keputusan petani lahan tadah hujan di Desa Ngaglik Kecamatan Gebang untuk melakukan irigasi suplementer dan kepemilikan ternak berpengaruh signifikan pada taraf nyata 5% terhadap keputusan petani lahan tadah hujan di Desa Harjobinangun Kecamatan Grabag untuk melakukan praktik konservasi lahan. 4) Strategi adaptasi petani lahan tadah hujan terhadap perubahan iklim dalam memenuhi kebutuhan air tanaman di Desa Ngaglik Kecamatan Gebang adalah memanfaatkan sumber air yang ada untuk memenuhi kebutuhan air tanaman dengan dukungan alat dan mesin pertanian (Alsintan) yang modern dan Penyuluh Pertanian Lapangan (PPL) sebagai mitra dan fasilitator petani. Sedangkan di Desa Harjobinangun adalah melakukan pengolahan lahan pertanian sesuai dengan prinsip konservasi tanah dan air dan memanfaatkan kelompok tani sebagai kelas belajar, wahana kerjasama dan unit produksi.
Kata Kunci: adaptasi perubahan iklim, petani lahan tadah hujan, kebutuhan air tanaman  

ABSTRACT
The impacts of climate change are abundantly experienced by the agricultural sector particularly the rainfed farming. The supply of water for rainfed farming is very much determined by rainfall conditions. Thus, the climate change causes the gap between its water supply and its water need. The objectives of this research are to investigate climate change conditions, adaptation forms, and influential factors to the adaptation and to formulate adaptation strategies for rainfed farmers as to fulfill the water need of crops in Ngaglik Village, Gebang Sub-district, and Harjobinangun Village, Grabag Sub-district, Purworejo Regency. This research used the descriptive quantitative method. Its data were collected through structured in-depth interview and observation and analyzed using descriptive analysis and logistic regression. The results of research are as follows: 1) The climate change in Ngaglik Village, Gebang Sub-district and in Harjobinangun Village, Grabag Sub-district has experienced a change in the form of a shifts on the peak of rainy season, the peak of dry season, early in the wet months, moist months and dry months, and types of climate. 2) The adaptation forms done by the rainfed farmers to the climate change as to fulfill the water need of crops in Ngaglik Village, Gebang Sub-district, Harjobinangun, Grabag Sub-district, Purworejo Regency include land conservation, supplementary irrigation, and water harvesting. 3) The supply of water resources has a significant effect at the real level of 5% on the decision of the rainfed farmers in Ngaglik Village, Gebang Sub-district, and Harjobinangun Village, Grabag Sub-district, Purworejo Regency to manage the supplementary irrigation, and the livestock ownership has a significant effect at the real level of 5% on the decision of the rainfed farmers in Ngaglik Village, Gebang Sub-district, and Harjobinangun Village, Grabag Sub-district, Purworejo Regency to conduct the land conservation. 4) The adaptation strategies by the rainfed farmers toward the climate change as to fulfill the water need of crops in Ngaglik Village, Gebang Sub-district , Purworejo Regency by utilizing the existing water sources to fulfill the water need of crops with the support of modern tools and agricultural machinery and the agricultural extension officers’ role as a partner and facilitator farmers. Menawhile, in Harjobinangun Village, Grabag Sub-district by doing the processing of agricultural land in accordance with the principle of conservation of soil and water and take advantage of farmer groups as classroom learning, rides cooperation and production units. Keywords: Adaptation to climate change, rainfed farmers, water need of crops