Drip irrigation scheduling for tomatoes in unheated greenhouses

Abstract

During the last two decades, energy-saving solar greenhouses without heating systems, about 150± 800 m 2 (width: 5±10 m, length: 30±80 m) in size, have been widely used in the North of China for vegetable production during cold seasons. The greenhouse is also suitable for use in other countries located in the temperate or warm-temperate zones, especially in the developing countries, because it is inexpensive with a simple structure, and does not need any additional energy for heating in winter. Drip irrigation has been recognized as a sensible method of supplying water inside the greenhouses, and a simple method for drip irrigation scheduling at low cost is urgently required. Using the water-balance method, the authors studied the water consumption of tomato (Lycopersicon esculentum Mill.) and the relationship between evapotranspiration and water surface evaporation measured with 20 cm pan. Research results show that there is no signi®cant water¯ux at 0.75 m depth when soil water potential is kept higher than ±20 kPa at 15 cm depth, and around ± 20 kPa at 60 cm depth. The accumulative value of evapotranspiration is approximately equal to the accumulative value of water surface evaporation measured using 20 cm pan. Further analysis found that 20 cm pan can be used to determine the water requirement of tomato drip irrigation scheduling in this type of greenhouse.

Effects of different water levels on cotton growth and water use through drip irrigation in an arid region with saline ground water of Northwest China

“…Nevertheless, information regarding the drip irrigation schedule and water management for cotton cultivation in this region is limited. Recently, a research group from the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences (IGSNRR, CAS) successfully established a drip irrigation schedule by controlling the soil matric potential (SMP) at a depth of 20 cm immediately under the emitter in the North China Plain, middle of the Hetao Plain and the coastal Zone of Tianjin for various crops and soil conditions (Yuan et al, 2001;Kang et al, 2004;Wan et al, 2007;Wan et al, 2010). Kang and Wan (2005) found an SMP of −35 kPa at a depth of 20 cm immediately under a drip emitter which could be used as an indicator for radish drip irrigation scheduling in the North China Plain.…”

Evaluación del Consumo de Agua de un Cultivo de Tomate en Invernadero Usando el Método de Priestley-Taylor

“…The WB method is described as follows (Yuan et al, 2001): [7] where ETreal is the real evapotranspiration of the crop (mm d -1 ); R is the amount of irrigation water supporting the system (mm d -1 ); ∆θs is the variation of soil water content (mm d -1 ); Es is the surface runoff (mm d -1 ); Pp is the water flow toward the deepest horizons (mm d -1 ). This balance did not consider surface runoff given that a drip irrigation system was used and there was a plastic cover over the soil that impeded lateral runoff of the water.…”

“…A correct determination of irrigation scheduling (irrigation timing and frequency) is one of the main factors in achieving high yields and avoiding loss of quality in greenhouse tomato (Yuan et al, 2001). To do this, it is fundamental to know the crop water requirements or real evapotranspiration (ETreal), which depends on specific interactions among soil, tomato crop and atmospheric conditions.…”

“…To do this, it is fundamental to know the crop water requirements or real evapotranspiration (ETreal), which depends on specific interactions among soil, tomato crop and atmospheric conditions. For greenhouses, ETreal have been estimated by measuring water evaporation with a Piche evaporimeter or modified evaporation pan (Kirda et al, 1988, Yuan et al, 2001. Also, the Penman-Monteith and PriestleyTaylor (PT) models, which have solid physical principles, could be used to estimate the tomato water requirements for greenhouses (Zhang and Lemeur, 1992;Ortega-Farías et al, 2004b).…”

The use of wind pumps for greenhouse microirrigation: A case study for tomato in Cuba

“…Under greenhouse conditions, evapotranspiration (ETr) is significantly reduced; greenhouse agriculture therefore offers a way to reduce crop water consumption and, as a consequence, decreases the energy needed for pressure irrigation. The ETr has been determined from the direct evaporation of water in Piche evaporimeters and modified evaporation trays (Kirda et al, 1988;Yuan et al, 2001) and by using models such as the Penman Monteith or Priestley Taylor, both of which are widely accepted (Zhang and Lemeur, 1992;Ortega-Farias et al, 2004).…”