sima asgharzaddanesh

Population growth requires extending agriculture and ranching to meet food demand and optimizing water use is necessary for a sustainable agriculture and ranching activities. To water use optimization in livestock production procedure, Amount of water utilized in diet ingredient producing and livestock drinking and servicing water should be noted. This amount of water used to produce livestock production called virtual water of production. The aim of this paper is computing virtual water of Holstein milk production in East Azerbaijan considering three irrigation efficiency 33, 60 and 90 percent. Average virtual water content of wheat, barley, corn, soybean, beet and alfalfa were 1.2, 1.5, 0.13, 3.8, 2.2 and 2.4 cubic meters per a kilogram production by considering 33 percent irrigation efficiency. According to 33 percent of irrigation efficiency the virtual water of milk for after parturition, high yielding, average yielding and low yielding durations were 1.5, 1.4, 2.4 and 3.3 cubic meters per a kilogram production. If percentage of irrigation efficiency increased by 60 and 90, virtual water of milk would decrease 43 and 60 percent respectively.

Soil water characteristic curve (SWCC) represents the quantative relationship between soil water content and matric suction. Direct measurement of this curve is laborious, time consuming and expensive. Hence, several experimental, mathematical and analytical models have been presented to describe the SWCC. In this research, 11 SWCC models were calibrated using volumetric water content and matric suction data of 27 soil samples of Qorveh-Dehgolan plain agricultural lands. Solver Toolbox in Excel used to calibrate the models and six other soil samples data used for result validation. The R2, RMSE, NRMSE and MBE statistics were used to assess the prediction accuracy of the models. According to the obtained results, for clay and loam textures, Libardi et al and Simmons et al models, for silty clay loam texture, Brooks and Corey model, for clay loam texture, Brooks and Corey and Campbell models, for silty clay texture, Van Genuchten m=1-2/n and Brooks and Corey models and for sandy loam texture, power model were proposed to predict soil water characteristic curve in the soils of the studied lands.