Adriana Bruggeman

Performance of Penman-Monteith FAO56 in a Semiarid Highland Environment

Reliable estimates of evapotranspiration are essential for irrigation and water resources planning and management. Although several methods are available for computing reference evapotranspiration ( ETo ) , the provision of complete and accurate climate data is often a problem. Therefore, weighing lysimeter data from a semiarid highland environment were used to evaluate the performance of six commonly used reference evapotranspiration estimation methods with different data requirements (Penman-Monteith-FAO56, Priestley-Taylor, Radiation-FAO24, Hargreaves, Blaney-Criddle, Class A pan). The lysimeter experiments were conducted at Ankara Research Institute of Rural Services in Turkey, during the April–October cropping seasons of the years 2000–2002. The average ETo for the three seasons, computed from the lysimeter data, was 964 mm. The Penman-Monteith-FAO56 method was also evaluated for cases where relative humidity, wind speed, solar radiation, or all three parameters would be missing. This resulted in a t...

Future of Drylands – An Overview of Evaluation and Impact Assessment Tools for Water Harvesting

In the arid regions of Tunisia, huge efforts are being made in the construction and maintenance of water harvesting and soil conservation structures. A growing need for their evaluation and assessment of their impact is felt. To this end, a simple tool has been developed and applied to evaluate the structural stability of jessour, tabias and gabion check dams. The total gives a measure of the structures present-day overall condition based on physical inspection of a number of key characteristics vital to its functionality. The evaluation tool was applied to a random sample of structures in southern Tunisia. This paper also describes an adaptation and evaluation of the ArcView soil and water assessment model (SWAT) for the assessment of the hydrologic impact of water harvesting systems. Some modifications were made to the model code to adapt the model to the processes in the study area. Evaluation of the hydrologic goodness-of-fit of the model based on the observed and simulated runoff data in the study site, using four statistical criteria, gave reasonable results.

Options to Improve Livelihoods and Protect Natural Resources in Dry Environments The Case of the Khanasser Valley in Syria

This article reviews work that had the objective of introducing agricultural technologies in a marginal dryland area, the Khanasser Valley, northwestern Syria. The highly variable rainfall is barely sufficient to support livelihoods in this traditional barley—livestock production system. The valley is representative of other marginal dryland areas in West Asia and North Africa. We used a farmer-participatory approach to evaluate the performance of agricultural technologies for dry marginal areas in terms of their contribution to livelihoods and effect on the environment. The integrated approach allowed comprehensively comparing and evaluating the viability of promising technologies, including novel crops, intercropping, soil management techniques, and livestock rearing. The results show that improved barley varieties, olives, cumin, and lamb fattening can improve livelihoods, particularly for the land-owning households, whereas other households can benefit indirectly in terms of employment spillovers. These options are also environmentally friendly and sustain the natural resource base.

Improved Decision Making for Deficit Irrigation of Wheat in Northern Syria

Increasing water scarcity due to population growth and urbanization is pushing the countries in the Mediterranean region to improve their irrigation water use efficiency. Supplemental irrigation of rain-fed crops is a very efficient use of the scarce water resources, but farmers often apply more water than is actually needed. The objectives of this study were to evaluate a model for scheduling of supplemental irrigation based on daily climate data and to assess irrigation requirements under different irrigation management options in northern Syria. The model used the FAO daily reference evapotranpiration and dual crop coefficient procedure for estimating irrigation requirements, but an addition was made to allow the storage of soil moisture below the developing root zone of rain-fed crops. The model performed satisfactorily for three years of data from a wheat trial at Tel Hadya in northern Syria, which has an average annual rainfall of 356 mm. The tested irrigation management options included the application of full irrigation at 50% depletion of the available soil water and irrigation of 67% of the soil water depletion at 75% of the available soil water (deficit irrigation). The deficit option was especially efficient in wet years, saving up to 84 mm, compared to full irrigation. The model will be further evaluated and developed in to an irrigation decision support tool.