Effects of deficit irrigation on yield and water use of greenhouse grown cucumber in the North China Plain

This study examines deficit irrigation on greenhouse grown cucumber in the North China Plain (NCP). The level of fulfillment of water requirements was used as a gauge to differentiate five border irrigation treatments. Fresh fruit yields were highly influenced by the total volume of irrigation water at every growth stage. The treatment with minimum irrigation water applied had the lowest productions. The mathematical functions that better fit for the production obtained with the water volume received were linearism, but the functions of evapotranspiration (ET) and yield were second-degree polynomials. The water use efficiency (WUE) and irrigation water use efficiency (IWUE) decreased with the increase of irrigation water applied from stem fruiting to the end, significantly since harvest of zenith fruits. But WUE and IWUE were ascending with the increase of irrigation water from cucumber field setting to first fruit ripening. Well irrigation along the whole cycle was a clearly advisable irrigation regime. On the other hand, the least advisable regimes were those that lead to deficiencies from harvest of the first fruit to the zenith fruits. But we strongly recommend actions be taken to limit the inefficient soil evaporation that resulted from higher temperature at the last growth stages in order to improve WUE and IWUE. (C) 2003 Elsevier Science B.V. All rights reserved.