Irrigation water requirements for some fruit trees specific to the Arges-Vedea river basin, Romania

This purpose of this paper is to present Penman-Monteith (PM) reference evapotranspiration values and estimates of crop coefficients (Kc) using the new method developed by Alien ct al. (1997), as well as crop evapotranspiration (ETc) and irrigation water requirements (IWRs) of some fruit trees within the Arges-Vedea river basin, Romania. Estimated Kc values for more crops were then compared to real Kc values obtained in field experiments under irrigation conditions. For some specific conditions, application of the procedure developed by Alien er al. (1997) resulted in Kc values almost equal or even lower for taller crops having a higher LAI than smaller-sized crops, due to the effect of the crop height exponent (h)(0.3) used in the Kc formula; therefore, small changes could be done in the formulae discussed in order to improve Kc estimates. A strong, highly significant correlation between estimated and real ETc values was obtained for the experimental periods used. However, ETc estimated by this method was systematically lower than real ETc previously reported for crops tested in this area. This could be attributed to the lack of accuracy involved in measurements of deep drainage and runoff in the earlier experiments lather than to the deficiency of Alien's method. For the peak months IWRs for the fruit trees studied here were interpolated using the kriging method, resulting in relatively homogeneous crop IWRs. This paper also aims to contribute to a better water management in this watershed.