scholarly journals Vapour pressure deficit control in relation to water transport and water productivity in greenhouse tomato production during summer

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Dalong Zhang ◽  
Qingjie Du ◽  
Zhi Zhang ◽  
Xiaocong Jiao ◽  
Xiaoming Song ◽  
...  
Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4667 ◽  
Author(s):  
Filippo Vurro ◽  
Michela Janni ◽  
Nicola Coppedè ◽  
Francesco Gentile ◽  
Riccardo Manfredi ◽  
...  

Environment, biodiversity and ecosystem services are essential to ensure food security and nutrition. Managing natural resources and mainstreaming biodiversity across agriculture sectors are keys towards a sustainable agriculture focused on resource efficiency. Vapour Pressure Deficit (VPD) is considered the main driving force of water movements in the plant vascular system, however the tools available to monitor this parameter are usually based on environmental monitoring. The driving motif of this paper is the development of an in-vivo sensor to monitor the effects of VPD changes in the plant. We have used an in vivo sensor, termed “bioristor”, to continuously monitor the changes occurring in the sap ion’s status when plants experience different VPD conditions and we observed a specific R (sensor response) trend in response to VPD. The possibility to directly monitor the physiological changes occurring in the plant in different VPD conditions, can be used to increase efficiency of the water management in controlled conditions thus achieving a more sustainable use of natural resources.


2002 ◽  
Vol 82 (4) ◽  
pp. 771-780 ◽  
Author(s):  
X. Hao ◽  
A. P. Papadopoulos

Two full spring season tomato crops (Lycopersicon esculentum Mill. “Trust”) were grown in an open rockwool system with standard rockwool feeding formulae (O-R; conventional method), and in closed rockwool systems with standard rockwool (C-R) or Nutrient Film Technique (C-NFT) feeding formulae (modified in 1997) in 1996 and 1997 to examine the feasibility of a fully closed rockwool production system with appropriate feeding formulae. The closed rockwool system with optimized feeding formulae achieved high marketable yield, similar to that of the open rockwool system. There were no differences in early plant growth, plant biomass or biomass partitioning, and in total fruit yield, size and grades except for the closed rockwool system with the standard rockwool feeding formulae (C-R), which had lower yield than C-NFT in the last month of harvest in 1996. The photosynthesis of old foliage was higher and the root systems at the end of the experiments were rated healthier in plants grown in the closed (C-R and C-NFT) systems than in plants grown in the open (O-R) system. Over 30% of water and fertilizer was saved with the closed systems in comparison to the conventional open system. These results demonstrated that closed rockwool systems with optimized nutrient feedings are economically and environmentally sound alternative methods for greenhouse tomato production in Ontario. Key words: Lycopersicon esculentum, tomato, yield, recycling, rockwool, greenhouse


1998 ◽  
Vol 25 (3) ◽  
pp. 287 ◽  
Author(s):  
Saman P. Seneweera ◽  
Oula Ghannoum ◽  
Jann Conroy

The hypothesis that shoot growth responses of C4 grasses to elevated CO2 are dependent on shoot water relations was tested using a C4 grass, Panicum coloratum (NAD-ME subtype). Plants were grown for 35 days at CO2 concentrations of 350 or 1000 µL CO2 L-1. Shoot water relations were altered by growing plants in soil which was brought daily to 65, 80 or 100% field capacity (FC) and by maintaining the vapour pressure deficit (VPD) at 0.9 or 2.1 kPa. At 350 µL CO2 L-1, high VPD and lower soil water content depressed shoot dry mass, which declined in parallel at each VPD with decreasing soil water content. The growth depression at high VPD was associated with increased shoot transpiration, whereas at low soil water, leaf water potential was reduced. Elevated CO2 ameliorated the impact of both stresses by decreasing transpiration rates and raising leaf water potential. Consequently, high CO2 approximately doubled shoot mass and leaf length at a VPD of 2.1 kPa and soil water contents of 65 and 80% FC but had no effect on unstressed plants. Water use efficiency was enhanced by elevated CO2 under conditions of stress but this was primarily due to increases in shoot mass. High CO2 had a greater effect on leaf growth parameters than on stem mass. Elevated CO2 increased specific leaf area and leaf area ratio, the latter at high VPD only. We conclude that high CO2 increases shoot growth of C4 grasses by ameliorating the effects of stress induced by either high VPD or low soil moisture. Since these factors limit growth of field-grown C4 grasses, it is likely that their biomass will be enhanced by rising atmospheric CO2 concentrations.


2008 ◽  
pp. 521-528 ◽  
Author(s):  
A.P. Papadopoulos ◽  
U. Saha ◽  
X. Hao ◽  
S. Khosla

2011 ◽  
Vol 12 (1) ◽  
pp. 19 ◽  
Author(s):  
W. M. Wintermantel

Potyviruses, transmitted by a diverse array of common aphid species, infect a broad range of vegetable crops, and can be problematic in greenhouse tomato production. Once introduced, these viruses are believed to be transmitted plant-to-plant during pruning operations, and can infect large sections of a greenhouse, resulting in significant losses in fruit quality and yield. Several methods are used for virus management in greenhouse production, including rouging of diseased plants and treatment of tools and facilities with virucides to eradicate the virus responsible. To clarify potyvirus transmission efficiency from an infected source during pruning operations, experiments were conducted using direct and serial mechanical inoculation of Potato virus Y (PVY) using a scalpel dipped in a suspension of PVY-infected plant sap. Tests demonstrated that both serial and direct inoculation resulted in significant PVY transmission, but that transmission rates declined after the first few plants in serial transmission. Additional tests evaluated the efficiency of two virucides, a quaternary ammonium solution and sodium hypochlorite, for virus inactivation during pruning operations using a range of concentrations and time points. Results demonstrated that 0.5% sodium hypochlorite treatment for two seconds was sufficient for virus control, and superior to treatment with quaternary ammonium solutions. Accepted for publication 20 December 2010. Published 21 February 2011.


Author(s):  
Bilge Gözener ◽  
Halime Dereli

Tomato comes as the most commonly produced, consumed and subject for trading in the world. Alongside fresh consumption, on the other hand it forms the most significant raw material source of food industry, especially for tomato paste, frozen and dried vegetable-fruit and canned food industry. Turkey's greenhouse vegetable production field for 2016 year is 675173 decars and Antalya forms 51% of this field. Tomato forms 61.72% of Antalya's greenhouse production. The main material of the research consists of interviews made with producers resided in 5 villages/towns, where greenhouse tomato production is carried out densely in Antalya city, Alanya district. In 48 villages and towns, greenhouse tomato production is carried out, according to the official records. In the chosen areas, 365 producers exist. 20% of these producers (73) form the sample size. In the research, it was determined that the producers' average agricultural land possession is 9.13 decars and in 40.53% of these areas they grew tomatoes. None of these producers are engaged in contractual growing. All of the yield is produced for the edible (as table-top item). After the harvest, all of the products are sold in the wholesales market in county and city. 7.89% of the producers have no information on soilless agriculture, as 10.52% of them think that it has no advantages and 73.36% of them recommend traditional agriculture.


2005 ◽  
Vol 48 (5) ◽  
pp. 815-824 ◽  
Author(s):  
Marcelo Schramm Mielke ◽  
Alex-Alan Furtado de Almeida ◽  
Fábio Pinto Gomes

Measurements of leaf gas exchange at different photosynthetic photon flux density (PPFD) levels were conducted in order to compare the photosynthetic traits of five neotropical rainforest tree species, with a special emphasis on empirical mathematical models to estimate the light response curve parameters incorporating the effects of leaf-to-air vapour pressure deficit (D) on the saturated photosynthetic rate (Amax). All empirical mathematical models seemed to provide a good estimation of the light response parameters. Comparisons of the leaf photosynthetic traits between different species needed to select an appropriate model and indicated the microenvironmental conditions when the data were collected. When the vapour pressure deficit inside the chamber was not controlled, the incorporation of linear or exponencial functions that explained the effects of D on leaf gas exchange, was a very good method to enhance the performance of the models.


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