Crop water requirement of Soursop (Annona muricata L) in Nawungan orchard, Selopamioro village, Imogiri sub-district, Bantul regency, Yogyakarta

The aim of this study was to to measure actual evapotranspiration and to determine of water requirement and crop coefficient (Kc) of of soursop (Annona muricata L). The soursop was farmed at Nawungan orchard in Selopamioro village, Imogiri sub-district. Village monographs, 1: 25,000 scale Indonesian earth map and climate data were used to get the purpose of study. An Automatic Weather Station (AWS) was installed in Nawungan orchard to record rainfall, air relative humidity, wind velocity, solar radiation, as well as soil moisture every fifteen minutes. A set of surface runoff equipment was set in soursop farming land. Infiltration test was conducted in nine selected locations of soursop farming land and later, it was used to find soil percolation value. The purposive sampling method was adopted to assign the nine locations of infiltration test. The reference evapotranspiration (ET₀) was calculated by the Penman-Monteith method. Later, water balance formula was applied to determine the actual plant water requirements (ET_a) and plant coefficient value (Kc). This study proved the reference evapotranspiration (ET₀) of the study area was 5.74 mm/day, the actual crop water requirement (ET_a) of soursop was 7.98 mm/day. And Kc of soursop was 0.576. © 2019 IOP Publishing Ltd. All rights reserved.