Crop water requirement calculations of Longan (Dimorcapus longan L.) in Nawungan Orchard, Selopamioro Village, Imogiri Sub-District, Bantul, D.I. Yogyakarta

This research was aimed to measure actual evapotranspiration, to determine of water requirement and crop coefficient (Kc) of longan (Dimorcapus longan Lour.) was cultivated in Longan Nawungan orchard, Selopamioro Village, Imogiri Sub-district. Plot scale of water balance was applied to determine ETa, with input components were rainfall and irrigation, while output were ETa, water storage (�SM), and surface runoff (SRO). Components of runoff was measured using tank and the moisture content was measured using gravimetry method. Automatic weather station was installed in Nawungan orchard to record rainfall, wind speed, air humidity, and intensity of solar radiation. Later, the climatic data were used to calculate the reference evapotranspiration (ETo) using Penman-Monteith method. Due to agroforestry and mix cropping system, longan trees were cultivated among seasonal crops and other trees, then the dual crop coefficient (Kc) was preffered. During February-Maret 2019, the value of rainfall and surface runoff were 640 mm during observation period and 0,08 mm, respectively. The reference evapotranspiration (ETo) and actual evapotranspiration (ETa) were 5,76 mm/day and 7,90 mm/day, respectively. The crop coefficient of longan in the site study area was 0,30. © 2019 IOP Publishing Ltd. All rights reserved.