دراسة اقتصادية تحليلية لكفاءة استخدام أنماط الري الحديثة: دراسة ميدانية بمزارع منطقة القصيم[An analytical economic study for the efficiency of water resources use in irrigation, “A field study at Al-Qassim region”]

The study aims to estimate the efficiency of water resources use for irrigation at Al-Qassim farms by estimating the productivity and technical efficiency, under different irrigation methods (sprinkler and drip irrigation) used for the main crops which are included in the sample of study, and estimating the demand functions for resources used in the production of main crops. The analysis based on the Data Envelopment Analysis (DEA), in addition to Total Factor Productivity (TFP) and parametric programming. The DEA is used with the constant and variant returns to scale (CRS and VRS) to estimate the technical efficiency and scale efficiency of the considered crops under different irrigation methods. The study sample (consists of 124 farms) was selected from the farms at Al-Qassim region, Data collected by the personal interview through a questionnaire which was prepared for this purpose, the study sample were representative the most important field and vegetable crops at the study area. The most important findings of the study can summarize as follows: (1) By estimation the technical (TE) and scale efficiency (SE) for the field and vegetable crops at the study sample according to the concept of VRS and CRS under different irrigation methods, the results show the following: * According to CRS hypothesis the average technical efficiency (TE) under mobile sprinkler irrigation method were lower for farms of wheat, barley, winter tomatoes, corn, summer tomatoes and alfalfa, while results refers to improvement of (TE) for these crops according to VRS hypothesis. * The average of scale efficiency (SE), which is (SE=TECRS / TEVRS) amounted to about 0.91, 0.89, 0.90, 0.91, 0.90, 0.90 under the mobile sprinkler irrigation system for the farms of wheat, barley, winter tomatoes, corn, summer tomatoes and summer cucumber. * According to CRS hypothesis the average technical efficiency (TE) under drip irrigation method were lower for farms of zucchini, winter tomatoes, winter cucumber, summer potatoes, summer tomatoes and summer cucumbers, while results refers to improvement of (TE) for these crops according to VRS hypothesis. * The average of scale efficiency (SE), was to about 0.86, 0.94, 0.83, 0.94, 0.94, 0.86 under the drip irrigation system for the farms of zucchini, winter tomatoes, winter cucumber, summer potatoes, summer tomatoes and summer cucumber. (2) The change in the index of total factor productivity (TFP Ch) of the quantity of production for winter tomatoes and summer tomatoes as a shift from the mobile sprinkler system to the drip system about 119%, 112% and refers to an opportunity to increase efficiency by 19%, 12%, while the change in the index of total factor productivity (TFP Ch) of the value of production for alfalfa as a shift from the fixed sprinkler system to the mobile sprinkler system about 103%. (3) By estimating the production and economic efficiencies based on stochastic frontier Analysis (SFA) using the ordinary least square (OLS) method and the maximum likelihood estimator (MLE) method. The (MLE) method was used under both the Truncated Distribution (TD) and Half-Normal Distribution (HND) techniques. The results indicated to the preference of MLE method in case of (HND) according to significance of γ to estimate the production efficiency of wheat, zucchini and alfalfa. While MLE method in case of (TD) according to significance of γ and the highest value of the LR was the best for crops winter and summer tomatoes, and winter and summer cucumbers. The OLS method was the fit to estimate the production efficiency of barley, corn and summer potatoes. (4) Using the parametric programming to identify the value of the marginal productivity (shadow prices) for each of the nitrogenous, phosphate fertilizers, agricultural employment and water resources. The results indicated that the shadow price of the unit (50 kg) for the resource of phosphate fertilizer up to about 69.1 SAR at the optimal use of the resource in the production of winter crops which follows the mobile sprinkler irrigation system, while up to about 131.3 SAR at the optimal use of the resource in the production of summer crops. For the resource of nitrogenous fertilizers used in the production of winter crops which follows the mobile sprinkler irrigation system, the shadow price of the unit (50 kg) up to about 295.4 SAR and up to about 68.7 SAR for the summer crops. For the labor resource used in the production of winter crops which follows the mobile sprinkler irrigation system, the shadow price of the unit (man / day) is approximately 52.3 SAR at the optimum utilization of the resource, while up to about 47.5 SAR to produce the summer crops.