It is estimated that the world population will be 9.6 billion by 2050. In order to meet the food needs of the growing population, it is necessary to increase the yield obtained from existing agricultural land. As the greenhouse provides a more controlled environment, the yield taken from the unit area is higher than the field conditions. For this reason, the greenhouse cultivation has been increased in year by year. Irrigation is one of the major cultural applications for increasing yield from the unit area. It is important that crop water requirement should be determined correctly for proper irrigation scheduling in greenhouse. The use of equations based on climate to determine evapotranspiration has been increased in recent years. In this study, estimation performances of evapotranspiration equations based on the reference crop (Penman, Hargreaves, FAO-24-Radiation, Priestley-Taylor, FAO-Penman Monteith, FAO24-Pan Evaporation) and main crop (Stanghellini, Fynn, Takakura, Simplified Model) developed from the past to the present day were reviewed. It is concluded that there is no standard equation under greenhouse conditions to determine evapotranspiration of a specific crop. The reason for this is that greenhouse climate changes depending on greenhouse type, location, direction, cover material, greenhouse volume, ventilation mechanism, usage of thermal curtain and shadow powder and even cultural applications such as hanging. However, it is possible to develop new equation or calibrate existing equations for each different greenhouse in the same region. Therefore, it is suggested that evapotranspiration equations to be used should be selected depending on the type of greenhouses commonly used in the region and, if necessary, modified according to these conditions.
Core Ideas
Lettuce yield was decreased by excessive nitrogen fertilization.
Deficit irrigation did not cause a decrease in yield.
Temperatures, photoperiod, and sunshine duration decreased the nitrate accumulation.
Nitrogen is one of the most important plant nutrients for lettuce (Lactuca sativa L. var. Kitare). However, excess use of N causes environmental and health problems. In this study, the response of lettuce plants to different amount of N and irrigation levels were studied. The experiment was conducted under glasshouse conditions for winter and spring growing seasons in Batı Akdeniz Agricultural Research Institute (BATEM), Antalya, Turkey. This study used a factorial design with three replications. Plant evapotranspiration varied from 14.4 to 28.8 and 16.3 to 32.6 L plant–1 in winter and spring, respectively. Nitrogen fertilizer levels affected lettuce yield in both growing seasons, whereas irrigation levels did not impact yield. The average yield varied from 354 to 472 g plant–1 in the winter growing season and from 333 to 611 g plant–1 in the spring growing season. The nitrate concentration in lettuce leaves increased with N rate and irrigation level, and was lower in spring than winter. The average nitrate accumulation varied from 4000 to 6000 and 2100 to 3600 mg kg–1, in the winter and spring growing season, respectively, exceeding the health standards of the European Union.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.