the past decades, lightweight, hand-held, portable, and battery operated infrared thermometers (IRT) became Corn (Zea mays L.) grown under a Mediterranean semiarid climate available. Infrared thermometers can rapidly measure requires supplemental irrigation to maximize the grain yield. Since the cost of irrigation application has been increasing, elimination of canopy temperatures over large areas. The theory of unnecessary irrigation applications would improve economics of corn IRT operation (Fuchs and Tanner, 1966; Fuchs et al., production. There has been much interest in the crop water stress 1967; Hatfield, 1990; Gardner and Shock, 1989); and index (CWSI) as a potential tool for irrigation scheduling and yield (Gardner et al., 1992a) and temperature effects in infraestimation. An experiment was conducted to monitor and quantify red thermometry (Jackson and Idso, 1969) have been water stress, and to develop parameters for irrigation scheduling and discussed. In the 1980s, the use of IRT become more grain yield of summer-grown corn as a function of CWSI under Mediroutine in irrigation scheduling when Idso et al. (1981a) terranean semiarid cropping conditions. Three irrigation treatments developed and demonstrated an empirical method for were based on replenishing the 0.9-m deep root zone to field capacity using the crop water stress index (CWSI). when the soil water level dropped to 25, 50, and 75% of available Idso et al. (1981a) observed a linear relationship bewater holding capacity (AWHC). A dryland treatment was also included. The lower (nonstressed) and upper (stressed) baselines were

Egypt produces half of the 20 million tons of wheat that it consumes with irrigation and imports the other half. Egypt is also the world's largest importer of wheat. The population of Egypt is currently growing at 2.2% annually, and projections indicate that the demand for wheat will triple by the end of the century. Combining multi-crop and -climate models for different climate change scenarios with recent trends in technology, we estimated that future wheat yield will decline mostly from climate change, despite some yield improvements from new technologies. The growth stimulus from elevated atmospheric CO 2 will be overtaken by the negative impact of rising temperatures on crop growth and yield. An ongoing program to double the irrigated land area by 2035 in parallel with crop intensification could increase wheat production and make Egypt self-sufficient in the near future, but would be insufficient after 2040s, even with modest population growth. Additionally, the demand for irrigation will increase from 6 to 20 billion m 3 for the expanded wheat production, but even more water is needed to account for irrigation efficiency and salt leaching (to a total of up to 29 billion m 3 ). Supplying water for future irrigation and producing sufficient grain will remain challenges for Egypt.

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Accurate and current rainfall characterization is an important tool for waterrelated system design and management. Updated rainfall intensity-duration-frequency (IDF) relationships in peninsular India were developed; impacts on runoff and groundwater recharge due to changes in rainfall characteristics are discussed. Two datasets were used from gauges in Hyderabad city, the capital of Andhra Pradesh: hourly rainfall data for the 19 years from 1993-2011 and daily rainfall data for the 30 years from 1982-2011. Hourly data were used to develop updated rainfall IDF relationships; daily data were used for trend analysis of threshold-based rainfall events. IDF curves were developed for return periods of 2, 5, 10, 15, 25, 50, 75, and 100 years for 1, 2, 4, 8, and 24 hour durations. The updated IDF relationships showed a significant change in rainfall characteristics compared to older relationships for the region surrounding Hyderabad, India; they showed greater rainfall

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Evaporation pans continue to be used extensively throughout the world to measure free-surface water evaporation (Epan) and to estimate evapotranspiration for irrigation scheduling and water management for agronomic and horticultural crops. Epan is also being used extensively to estimate evaporation rates from lakes, wetlands, rivers, reservoirs, and other water bodies for management of wildlife and ecological habitat. A reliable method is needed to estimate missing daily Epan data. Determination of a reliable method for the estimation of Epan would also be useful in modeling of crop growth, and hydrological and ecological systems. Five methods [Penman (Penman, 1948), Kohler-Nordenson-Fox (KNF) (Kohler et al., 1955), Christiansen (Christiansen, 1968), Priestley-Taylor (PT) (Priestley and Taylor, 1972), and Linacre (Linacre, 1977)] for estimating Epan were compared with the historical (23-year) measured daily values to determine the suc- cess of accurate and consistent Epan estimations under humid climatic conditions in Florida. The root mean square error (RMSE) was used as the criteria to judge the accuracy and reliability of a given method. An RMSE value of <0.5 mm·d-1 (0.02 inches/d) between the measured and estimated Epan was considered as an acceptable error for daily estimations. The standard deviation (sd) values, and percent error (%E) between the estimated and measured values were also considered in the performance evaluations. Performance evaluations of the Epan estimates of the methods were made on a daily, monthly, and annual basis. Results indicated that the KNF method provided the best Epan estimations. The Linacre method yielded the poorest estimates. The second, third, and fourth best methods were the Penman, PT, and Christiansen, respectively. The RMSE and sd of Epan estimates were lowest when using KNF method. The mean value of the %E of daily, monthly, and annual estimations were 27%, 27%, and 26% for Christiansen; 6%, 6%, and 4% for KNF; 33%, 32%, and 26% for Linacre; 24%, 24%, and 21% for PT; and 19%, 17%, and 11% for Penman methods, respectively. The weekly, monthly, and annual total of Epan estimates from KNF method were also compared to the measured values of the two selected years of data (1981 and 1983). The annual rainfall totals were significantly lower than the 23-year mean in 1981, and higher in 1983. The %Es of weekly, monthly, and annual total Epan estimates were 9%, 9%, and -1% in 1981; and 11%, 5%, and 4% in 1983, respectively. The KNF method underestimated Epan in 1981 (dry year) and the underestimations were higher in summer months. The underestimations in a dry year, especially in summer months, might be due to the fact that the sensible heat advection is not effectively accounted for in the KNF equation causing underestimations of Epan. Overall results indicated that the KNF method should be the first choice, among the methods tested, for estimating daily Epan for irrigation scheduling and for estimating the missing Epan data in humid areas.