M. Gallardo

Universidad de Almería | UAL · Department of Agronomy

Increasing salinization of groundwater used for irrigation is a current and growing problem for vegetable production in greenhouses in the Mediterranean Basin. Vegetable growers in this system require clear information of crop response to salinity, particularly of threshold values. For sweet pepper in Mediterranean greenhouses, this work (i) evalua...

Substrate-grown crops represent approximately 10% of the cropping area of intensive greenhouse horticulture in southern Spain. The vast majority are free draining, in that they do not collect and recirculate drainage. The substantial nutrient loss in drainage contributes to contamination of water bodies. This study examined the effectiveness of dyn...

El aumento de la salinidad del agua en invernaderos de Almería requiere la aplicación de riegos de lavado para evitar pérdidas de producción lo cual provoca lixiviación de NO3- y contaminación de acuíferos. El objetivo de este trabajo fue desarrollar una estrategia de gestión integrada del fertirriego manteniendo la producción y minimizando la lixi...

Most agro-hydrological modelling studies of fertigated crops published in the literature are based on classical model identification approaches, in which a single and optimal representation of the water/nitrogen balance and crop biomass production is sought, through the calibration of model parameters. Here, the concept of an optimal parameter set...

The VegSyst model, initially developed for nitrogen (N) and irrigation recommendations for greenhouse-grown vegetable crops, was adapted for outdoor conditions, for lettuce, spinach and processing tomato. The major change introduced into the existing VegSyst model was to include evaporative demand, as transpiration use efficiency (TUE), as an additio...

Intensive vegetable production is commonly associated with excessive nitrogen (N) fertilization and associated environmental problems. Monitoring of crop N status can enhance crop N management. Chlorophyll meters (CMs) could be used to monitor crop N status because leaf chlorophyll (chl) content is strongly related to crop N status. To monitor crop...

In the coming few years, one of the major challenges for the vegetable industry will be to ensure sufficient production for the increasing world population in a sustainable way, with improved water and nutrient use efficiency. Therefore, vegetable growers and extension specialists should shift from maximizing yield per unit of production area to ma...

The VegSyst simulation model has been developed for use in an on-farm decision support system (DSS) to estimate crop N and irrigation requirements of different vegetable crops grown in plastic greenhouses in the Mediterranean Basin. The only inputs are readily available daily climatic data of air temperature, solar radiation and roof transmissivity...

Optimal and sustainable N management is required for profitable crop production and to minimize nitrate leaching to the environment. In fertigated vegetable crops, N is often applied continuously throughout the crop, so such management requires accurate and quick on-farm diagnosis of crop N status to enable rapid correction of the N fertilizer rate...

The capacity of the EU-Rotate_N model to simulate agronomic parameters (dry matter production, yield, crop N uptake, evapotranspiration (ETc), soil water content dynamics) and parameters associated to nitrate (NO3⁻) pollution (drainage, NO3⁻ leaching, accumulation of mineral N in soil) was evaluated in sequences of melon and pepper crops grown in p...

Large nitrogen (N) fertilizer applications are a feature of intensive vegetable production systems, and optimal N management is required to maximize N use efficiency and minimize N losses. Vegetation indices (VIs) of canopy reflectance, measured with proximal sensors, are generally strongly related to crop N status. For practical application, suffi...

The simulation model VegSyst was parameterized and verified for an open-Air lettuce (Lactuca sativa L.) crop. Parameterization was performed with data of a field experiment conducted in California in 1994 (Gallardo et al., 1996) and verification with experiments conducted in Cordoba (Spain) in 2002 and Granada (Spain) in 2011. Daily dry matter prod...

Greenhouse vegetable production systems require high N and irrigation inputs. Commonly, these systems are associated with environmental problems caused by nitrate leaching. Given increasing societal pressure to reduce these problems, there is a requirement to optimally use N and water inputs. Optimal management practices will be influenced by the g...

Sustainable N management of intensive vegetable crops requires accurate and timely on-farm assessment of crop N status. Proximal fluorescence-based sensors are promising tools for monitoring crop N status, by providing non-destructive optical measurements of N-sensitive indicator compounds such as chlorophyll and flavonols. The ability of the Multi...

Evaluation of crop N status will assist optimal N management of intensive vegetable production. Simple procedures for monitoring crop N status such as petiole sap [NO3−–N], leaf N content and soil solution [NO3−] were evaluated with indeterminate tomato and muskmelon. Their sensitivity to assess crop N status throughout each crop was evaluated usin...

Sustainable and optimal economic N management requires correct and timely on-farm assessment of crop N status to detect N deficiency or excess. Optical sensors are promising tools to assess crop N status throughout a crop or at critical times. The ability of optical sensor measurements of canopy reflectance (Crop Circle ACS 470) and leaf chlorophyl...

Nitrogen losses from intensive vegetal production systems are commonly associated with contamination of water bodies. Sustainable and optimal economic N management requires correct and timely on-farm assessment of crop N status to detect N deficiency or excess. Optical sensors are promising tools for the assessment of crop N status throughout a cro...

The simulation model VegSyst was calibrated and validated for tomato grown under plastic cover. Calibration was conducted with an autumn-winter soil-grown crop, and validation with five crops with differences in season, cropping media, and site. VegSyst accurately simulated daily dry matter production (DMP), N uptake, and ETc. Comparing simulated a...

This chapter deals with the basic principles of plant water relations. Firstly, the role of water in plants is described. The traditional indicators of plant water status are presented together with new methodological approaches that have been recently developed to characterize plant water status. Then, the development of water deficits is consider...

Free-draining soilless culture is commonly used in greenhouses in the Mediterranean Basin, frequently with tomato. Crop N uptake concentration has been proposed as a tool to assist with N management of crops in soilless culture. Three tomato crops were grown in free-draining rocicwool to evaluate the relationship of crop N uptake concentration to c...

A very significant event in the world history of Agriculture is the domestication of plants by mankind. Instead of depending on wild growth, it was realized that the planting of seeds or cuttings allowed the propagation of the type of plants desired. Another important breakthrough resulted from the need to protect the domesticated plants from abiot...

The combined use of fertigation and drip irrigation to frequently apply small amounts of N throughout a crop provides the technical capacity for precise N and irrigation management. A prescriptive–corrective management (PCM) package, based on modeling and monitoring approaches, was developed for combined irrigation and N management to take advantag...

The VegSyst simulation model was developed to assist with N and irrigation management of sweet pepper grown in plastic greenhouses in the Mediterranean Basin. The model was developed for use in an on-farm decision support system with the requirement for readily available input data. Dry matter production (DMP), crop N uptake and crop evapotranspira...

Like many intensive vegetable production systems, the greenhouse-based system on the south-eastern (SE) Mediterranean coast of Spain is associated with considerable NO3− contamination of groundwater. Drip irrigation and sophisticated fertigation systems provide the technical capacity for precise nutrient and irrigation management of soil-grown crop...

The standard FAO methodology for the determination of crop water requirements uses the product of reference evapotranspiration (ETo) and crop coefficient values. This methodology can be also applied to soil-grown plastic greenhouse crops, which occupy extended areas in the Mediterranean basin, but there are few data assessing methodologies for esti...

Free-drainage or "open" substrate system used for vegetable production in greenhouses is associated with appreciable NO3- leaching losses and drainage volumes. Simulation models of crop N uptake, N leaching, water use and drainage of crops in these systems will be useful for crop and water resource management, and environmental assessment. This wor...

Small analytical systems enabling rapid on-farm analysis may be useful for monitoring crop and soil nutrient status. Two commercially available, rapid analysis systems were evaluated for analysis of [NO3-] in aqueous standard solutions (AS), and in soil solution (SS), plant sap (PS) and fertigation nutrient solutions (NS) obtained from tomato crops...

There is increasing pressure to reduce water use and environmental impact associated with open system, soil-less production in simple, plastic greenhouses on the Mediterranean coast. This may force the adoption of re-circulation of nutrient solutions. In south-eastern Spain, irrigation water is mostly from aquifers and has moderate levels of salini...

Three field experiments examined the effects of soil salinity on volumetric soil water content (SWC) measured with a capacitance sensor (CS). They were conducted in field-grown vegetable crops fertigated with complete nutrient solutions. Experiment 1 compared nutrient solutions with electrical conductivities (ECns,) of 6.5 dS m(-1) ((+)SAL) and 2.4...

Thresholds of soil matric potential (SMP) and available soil water content (AWC) required to prevent water limitations between irrigations were determined for bell pepper, melon, and spring and winter tomato grown in Mediterranean-type greenhouses on the south-eastern coast of Spain. Thresholds were identified by measuring the divergence of leaf wa...

Considerable NO3− contamination of underlying aquifers is associated with greenhouse-based vegetable production in south-eastern Spain, where 80% of cropping occurs in soil. To identify management factors likely to contribute to NO3− leaching from soil-based cropping, a survey of irrigation and N management practices was conducted in 53 commercial...

In situ approaches for determining lower limit (threshold, refill) values for irrigation management using continuously monitored data from volumetric soil water content (SWC) sensors were evaluated. Four indices were derived from SWC data: (i) apparent daily crop water uptake (ADCWU), the reduction in SWC during daylight periods; (ii) daily soil wa...

The sensitivity of stem diameter variations (SDV) measured with linear variable transducer (LVDT) sensors as indicators of plant water status in tomato was evaluated. Two tomato crops were grown sequentially in a sandy loam soil in an unheated plastic greenhouse. These were an autumn–winter tomato crop (autumn crop) and a spring–summer tomato crop...

The ability of stem diameter measurements to detect water stress in mature vegetable crops, grown in greenhouses, was evaluated in tomato and melon grown in soil. Water stress was applied by withholding irrigation, for 9 days in tomato, and for 10 days in melon. In both crops, there were well-irrigated control plants. The treatments were applied wh...

Cultivated crisphead lettuce (Lactuca sativa L.) has a shallower root system than its wild relative, Lactuca serriola L. The effects of localized soil water, at depth, on plant water relations, gas exchange and root distribution were examined in the two species using soil columns with the soil hydraulic-ally separated into two layers, at (0–20 cm a...

Considerable nitrate (NO3 - ) contamination of underlying aquifers is associated with greenhouse vegetable production in Almeria, Spain. Eighty percent of cropping occurs in soil, the rest in “open” hydroponic systems. To identify the management factors associated with NO3 - leaching loss from soil-based cropping, a survey of irrigation and N manag...

In the near future, it is likely that closed soilless growing systems will be increasingly adopted in Mediterranean countries because they reduce water and fertiliser use, and appreciably reduce nutrient loss to the environment. However, closed systems increase the salinity of the circulating nutrient solution through the progressive accumulation o...

Large unheated greenhouse areas are located in the coastal lands of the Mediterranean Basin, based on low-cost structures covered with plastic. Water is a scarce resource in these areas and therefore it is necessary to optimise irrigation practice by applying the crop water needs, thus avoiding waste. This work was undertaken to determine the water...

The Watermark 200SS sensor was evaluated for the measurement of soil matric potential (SMP) with drip-irrigated vegetable crops. Pepper and melon crops were grown sequentially during autumn-winter and spring-summer, in a sandy loam soil in a greenhouse. Ranges of SMP were generated by applying three different irrigation treatments — 100, 50 and 0%...

Sweet pepper, grown from Autumn to Spring, is a major crop in greenhouse vegetable production systems of the Mediterranean coast in south-eastern Spain. Irrigation water is limited in this region, yet little information is available to assist in irrigation management at the farm and regional levels. The aim of this work was to determine crop evapot...

In this paper the influence of nutrition on fruit quality of a tomato soilless crop is reported. Five treatments were carried out with decreasing levels of NO3-, K+ and Ca2+ which were maintained during all the cropping period. The plants, grown in perlite-bags, were irrigated under moderate salinity conditions, keeping constant the sodium chloride...

The objective of this work was to improve irrigation scheduling of pepper crops grown in plastic greenhouses in the region of Almeria, Spain. The experimental approach was to determine crop coefficient (Kc) values for a pepper crop grown under representative greenhouse conditions in Almeria, Kc being the ratio between crop evapotranspiration (ETc)...

Crop evapotranspiration (ETc) by crisphead lettuce varies considerably with weather conditions and irrigation management. Accurate estimates of ETc will enable irrigation applications to be matched more closely to crop requirements, which will reduce excessive applications of irrigation water. This is important in the Salinas Valley, Calif., where...

The effects of a variable water supply on the water use, growth and yield of two crisphead and one romaine (i.e., Cos) lettuce cultivar were examined in a field experiment using a line source sprinkler system that produced a range of water regimes that occur in growers fields. Four locations at increasing distances from the main line were monitored...

The effects of a variable water supply on the water use, growth and yield of two crisphead and one romaine (i.e., Cos) lettuce cultivar were examined in a field experiment using a line source sprinkler system that produced a range of water regimes that occur in growers fields. Four locations at increasing distances from the main line were monitored...

Previous studies have shown similar water use for lupins ( Lupinus angustifolius L.) and wheat ( Triticum aestivum L.), despite a considerably smaller root system in lupins. A field study and an experiment under controlled conditions using pressure-flux relationships were conducted to examine whether higher hydraulic conductances were responsible f...

Soil columns in which the root system was divided into three equal layers, each 24 cm in diameter and 33 cm high were used to examine the influence of drying different proportions of the root system on the water relations, gas exchange and abscisic acid (ABA) concentration of lupin (Lupinus cosentinii Guss. cv. Eregulla) leaves. The treatments impo...

In the search for alternative crops suitable for rainfed mediterranean cropping systems, a new species of cereal × Tritordeum Ascherson et Graebner (Hordeum chilense Roem. et Schultz. × Triticum spp.) has been bred by crossing a wild barley with bread and durum wheats. The productivity and agro nomic characteristics of two experimental lines of tri...

The new species of cereal Tritordeum Ascherson et Graebner (Hordeum chilense Roem. et Shultz Triticum ssp.) has a grain protein concentration (GPC) of up to 25%. The relationship between GPC and yield, and the factors responsible for the high GPC of tritordeum were examined and compared in field experiments. Three experimental tritordeum lines, two...

This work evaluated the effect of soil salinity on measurement of the volumetric soil water content (SWC) made with a capacitance sensor (CS). The work was conducted in an unrestricted clay soil, in a plastic greenhouse, that was cropped with tomato. High frequency drip irrigation was used and complete nutrient solutions were applied in most irriga...