scholarly journals Computation of vapour pressure deficit and crop transpiration via development of a web based computer module

2021 ◽  
Vol 23 (4) ◽  
pp. 381-388
Author(s):  
MAHESH CHAND SINGH ◽  
J. P. SINGH ◽  
K. G. SINGH ◽  
O. P. GUPTA ◽  
G. KUMAR
Keyword(s):  
Vapour Pressure ◽  
Crop Yields ◽  
Production Systems ◽  
Vapour Pressure Deficit ◽  
Climatic Conditions ◽  
Effect Of Temperature ◽  
Plant Water ◽  
Web Based ◽  
Microclimatic Conditions ◽  
Cucumber Yield

The plant water or nutrient requirement under greenhouse conditions is mainly governed by crop transpiration in a linear relation to vapour pressure deficit (VPD), particularly in soilless production systems. Being a cooling process in plants, transpiration governs the plant water requirement in relation to the subjected microclimatic conditions and VPD can be used as a tool to maintain greenhouse crop transpiration to optimal range for obtaining desired crop yields. Thus, the present investigation was undertaken to study the integrated effect of temperature (Tapc), relative humidity (Eapc) and solar radiation (Irad) on VPD and crop transpiration. A computer module was developed to monitor the behavior of the VPD and thereby the crop transpiration through charts under greenhouse conditions. The VPD indicated a linear increasing trend with Tapc (R2≥0.84) and decreasing trend with Eapc (R2=0.99), demonstrating a strong correlation in both cases. The increasing crop transpiration with VPD, particularly under hot climatic conditions significantly increased the input water and nutrient requirements of the crop. Thus, transpiration in relation to VPD should be considered as a factor for fertigation scheduling and improving irrigation control in soilless systems. Moreover, maintaining Tapc, Eapc and VPD within range of 22-27°C, 60-80% and 0.53-1.10 kPa may help to control the crop transpiration, manage the greenhouse irrigation and fertigation, and thus improve the cucumber yield.

Effect of Temperature, Vapour-Pressure Deficit and Irradiance on Transpiration Rates of Maize, Paspalum, Westerwolds and Perennial Ryegrasses, Peas, White Clover and Lucerne

1977 ◽  
Vol 4 (6) ◽  
pp. 889 ◽  
Author(s):  
BJ Forde ◽  
KJ Mitchell ◽  
EA Edge
Keyword(s):  
Water Use ◽  
Transpiration Rate ◽  
White Clover ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Effect Of Temperature ◽  
Climate Conditions ◽  
Growth Environment ◽  
Temperature Regimes ◽  
C3 Species

Rates of water use [g H2O (g dry wt leaf)-1 h-1] of young plants of maize, paspalum, perennial ryegrass, Westerwolds ryegrass, peas, white clover and lucerne were measured during the day under controlled climate conditions with ample water available to the plant. Plants were grown and observations made with day/night temperatures of 32.5/27.5°C, 27.5/22.5°, 22.5/17.5°, and 17.5/12.5°C with a day/night vapour pressure deficit (VPD) of the air of 10/2mbar. Water use measurements were also made at 27.5/22.5° and 17.5/12.5°C under day/night VPD regimes of 5/2 and 15/2 mbar. Irradiance during the 12-h day was 170 W m-2 (400-700 nm). Further water use determinations were made at the four temperature regimes under 10/2 mbar VPD and an irradiance of 60 W m-2 (400-700 nm). For a given species, transpiration rates increased with temperature at constant VPD under both irradiance environments, by factors ranging from 1.4 to 2.3. Transpiration rates of maize and paspalum (C4) were lower at a given temperature than were the rates of the C3 species, while lucerne and clover had the highest rates. Water use by lucerne was 2.5 to 3.5 times that of maize. Transpiration rates of maize and paspalum were lower under 60 W m-2 than under 170 W m-2 but irradiance had little effect on transpiration rate of the C3 species. Though transpiration rate generally increased with increasing VPD, the difference in rates between plants at 5 mbar and 10 mbar VPD was much greater than between 10 mbar and 15 mbar. The physiological adaption of different species to their growth environment is discussed, and the implications of the results with reference to water loss by young, single-spaced plants in the field is outlined.

scholarly journals Toward a Reduced Reliance on Conventional Pesticides in European Agriculture

Plant Disease ◽  
2016 ◽  
Vol 100 (1) ◽  
pp. 10-24 ◽  
Author(s):  
Jay Ram Lamichhane ◽  
Silke Dachbrodt-Saaydeh ◽  
Per Kudsk ◽  
Antoine Messéan
Keyword(s):  
Crop Production ◽  
Crop Yields ◽  
Production Systems ◽  
Integrated Management ◽  
Crop Protection ◽  
Sustainable Use ◽  
Climatic Conditions ◽  
Pesticide Use ◽  
Eu Member States ◽  
European Agriculture

Whether modern agriculture without conventional pesticides will be possible or not is a matter of debate. The debate is meaningful within the context of rising health and environmental awareness on one hand, and the global challenge of feeding a steadily growing human population on the other. Conventional pesticide use has come under pressure in many countries, and some European Union (EU) Member States have adopted policies for risk reduction following Directive 2009/128/EC, the sustainable use of pesticides. Highly diverse crop production systems across Europe, having varied geographic and climatic conditions, increase the complexity of European crop protection. The economic competitiveness of European agriculture is challenged by the current legislation, which banned the use of many previously authorized pesticides that are still available and applied in other parts of the world. This challenge could place EU agricultural production at a disadvantage, so EU farmers are seeking help from the research community to foster and support integrated pest management (IPM). Ensuring stable crop yields and quality while reducing the reliance on pesticides is a challenge facing the farming community is today. Considering this, we focus on several diverse situations in European agriculture in general and in European crop protection in particular. We emphasize that the marked biophysical and socio-economic differences across Europe have led to a situation where a meaningful reduction in pesticide use can hardly be achieved. Nevertheless, improvements and/or adoption of the knowledge and technologies of IPM can still achieve large gains in pesticide reduction. In this overview, the current pest problems and their integrated management are discussed in the context of specific geographic regions of Europe, with a particular emphasis on reduced pesticide use. We conclude that there are opportunities for reduction in many parts of Europe without significant losses in crop yields.

scholarly journals Identifying meteorological drivers of extreme impacts: an application to simulated crop yields

2021 ◽  
Author(s):  
Jakob Zscheischler ◽  
Johannes Vogel ◽  
Pauline Rivoire ◽  
Cristina Deidda ◽  
Leila Rahimi ◽  
...  
Keyword(s):  
United States ◽  
Vapour Pressure ◽  
Crop Yields ◽  
Model Performance ◽  
Vapour Pressure Deficit ◽  
Growing Season ◽  
The United States ◽  
Climate Extreme ◽  
Crop Failure ◽  
Grid Points

<p>Compound weather events may lead to extreme impacts that can affect many aspects of society including agriculture. Identifying the underlying mechanisms that cause extreme impacts, such as crop failure, is of crucial importance to improve their understanding and forecasting. In this study we investigate whether key meteorological drivers of extreme impacts can be identified using Least Absolute Shrinkage and Selection Operator (Lasso) in a model environment, a method that allows for automated variable selection and is able to handle collinearity between variables. As an example of an extreme impact, we investigate crop failure using annual wheat yield as simulated by the APSIM crop model driven by 1600 years of daily weather data from a global climate model (EC-Earth) under present-day conditions for the Northern Hemisphere. We then apply Lasso logistic regression to determine which weather conditions during the growing season lead to crop failure.</p><p>We obtain good model performance in Central Europe and the eastern half of the United States, while crop failure years in regions in Asia and the western half of the United States are less accurately predicted. Model performance correlates strongly with annual mean and variability of crop yields, that is, model performance is highest in regions with relatively large annual crop yield mean and variability. Overall, for nearly all grid points the inclusion of temperature, precipitation and vapour pressure deficit is key to predict crop failure. In addition, meteorological predictors during all seasons are required for a good prediction. These results illustrate the omnipresence of compounding effects of both meteorological drivers and different periods of the growing season for creating crop failure events. Especially vapour pressure deficit and climate extreme indicators such as diurnal temperature range and the number of frost days are selected by the statistical model as relevant predictors for crop failure at most grid points, underlining their overarching relevance.</p><p>We conclude that the Lasso regression model is a useful tool to automatically detect compound drivers of extreme impacts, and could be applied to other weather impacts such as wildfires or floods. As the detected relationships are of purely correlative nature, more detailed analyses are required to establish the causal structure between drivers and impacts.</p>

Limited-transpiration rate under high atmospheric vapour pressure deficit: a trait for developing genotypes for water-deficit conditions.

2019 ◽  
Vol 14 (057) ◽  
Author(s):  
Michel Edmond Ghanem
Keyword(s):  
Soil Water ◽  
Transpiration Rate ◽  
Vapour Pressure ◽  
Crop Yields ◽  
Plant Traits ◽  
Stomatal Closure ◽  
Vapour Pressure Deficit ◽  
Breeding Strategy ◽  
Potential Benefits ◽  
Specific Trait

Abstract Water deficits are the major limitation in increasing crop yields in many regions of the world. Various plant traits that might result in yield increases in water-limited environments have been discussed for decades. Conservative use of soil water is an important breeding strategy in drought-prone environments that can be achieved by traits based on partial stomatal closure under specific environmental conditions to limit transpiration rate (TR). The focus of this review is on a specific trait for conservative soil water that results in partial stomatal closure that can be supported by a plant. This limit on TR is expressed in terms of the atmospheric vapour pressure deficit (VPD) at which partial stomatal closure occurs. The review provides the physiological background of partial stomatal closure under elevated VPD. Simulation studies that analyse the potential benefits of this trait are also discussed. Finally, we provide a review of the various research that has been made in the identification of genetic variability of this trait in major crops.

Complex edge effects on soil moisture and microclimate in central Amazonian forest

1995 ◽  
Vol 11 (2) ◽  
pp. 205-221 ◽  
Author(s):  
J. L. C. Camargo ◽  
V. Kapos
Keyword(s):  
Soil Moisture ◽  
Edge Effects ◽  
Vegetation Structure ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Forest Edge ◽  
Vertical Profiles ◽  
Control Soil ◽  
Neutron Probe ◽  
Microclimatic Conditions

ABSTRACTWe investigated the influence of a four-year-old forest edge near Manaus, Brazil, on soil moisture and vertical profiles of air vapour pressure deficit (VPD) within the forest. Soil moisture was measured (with a neutron probe) 0, 5, 10, 20, 40, 60, 80, 100, 150 and 200 m into the forest from the edge, in undisturbed control areas, and in the pasture. Control soil moisture was better explained by rainfall in the previous 2 or 10 days than by longer-term totals. Soil water potentials ≤ – 1.5 MPa occurred at some forest locations during the driest period. The variation in soil moisture with distance from the forest edge was complex, with higher values just inside the edge and depleted zones at the edge and 40–80 m inside it. At a given height, VPD (standardized relative to measurements in the open) was not related to distance from the edge, but VPD increased more with height near the edge than in control areas. The complexity of the edge's influence and the contrast with earlier data from the same edge can be explained by the changing vegetation structure near the edge. Regrowth ‘seals’ the edge with more leaves that transpire and deplete soil moisture, while protecting the understorey just inside the edge from desiccating conditions. A mosaic of gaps of differing ages develops behind the edge, increasing the variation in microclimatic conditions near the ground and consequently in evapotranspiration and soil moisture.

scholarly journals Component traits of plant water use are modulated by vapour pressure deficit in pearl millet (Pennisetum glaucum (L.) R.Br.)

2016 ◽  
Vol 43 (5) ◽  
pp. 423 ◽  
Author(s):  
Jana Kholová ◽  
Paul Zindy ◽  
Srikanth Malayee ◽  
Rekha Baddam ◽  
Tharanya Murugesan ◽  
...  
Keyword(s):  
Pearl Millet ◽  
Water Use ◽  
Vapour Pressure ◽  
Pennisetum Glaucum ◽  
Vapour Pressure Deficit ◽  
Leaf Expansion ◽  
Plant Water ◽  
Terminal Drought ◽  
Plant Water Use ◽  
Leaf Expansion Rate

Traits influencing plant water use eventually define the fitness of genotypes for specific rainfall environments. We assessed the response of several water use traits to vapour pressure deficit (VPD) in pearl millet (Pennisetum glaucum (L.) R.Br.) genotypes known to differ in drought adaptation mechanisms: PRLT 2/89–33 (terminal drought-adapted parent), H 77/833–2 (terminal drought-sensitive parent) and four near-isogenic lines introgressed with a terminal drought tolerance quantitative trait locus (QTL) from PRLT 2/89–33 (ICMR01029, ICMR01031, ICMR02042, and ICMR02044). Plant water use traits at various levels of plant organisation were evaluated in seven experiments in plants exposed either transiently or over the long term to different VPD regimes: biomass components, transpiration (water usage per time unit) and transpiration rate (TR) upon transient VPD increase (g H2O cm–2 h–1)), transpiration efficiency (g dry biomass per kg H2O transpired), leaf expansion rate (cm per thermal time unit) and root anatomy (endodermis dimensions)). High VPD decreased biomass accumulation by reducing tillering, the leaf expansion rate and the duration of leaf expansion; decreased root endodermis cell size; and increased TR and the rate of TR increase upon gradual short-term VPD increases. Such changes may allow plants to increase their water transport capacity in a high VPD environment and are genotype-specific. Some variation in water use components was associated with terminal drought adaptation QTL. Knowledge of water use traits’ plasticity in growth environments that varied in evaporative demand, and on their genetic determinacy, is necessary to develop trait-based breeding approaches to complex constraints.

scholarly journals Sustainable Intensification in Agriculture: An Approach for Making Agriculture Greener and Productive

2021 ◽  
Vol 7 ◽  
pp. 133-150
Author(s):  
Jiban Shrestha ◽  
Subash Subedi ◽  
Krishna Prasad Timsina ◽  
Sudeep Subedi ◽  
Meena Pandey ◽  
...  
Keyword(s):  
Crop Production ◽  
Crop Yields ◽  
Production Systems ◽  
Climatic Conditions ◽  
Sustainable Intensification ◽  
Modern World ◽  
Agronomic Practices ◽  
Farm Mechanization ◽  
Use Efficiency

Sustainable intensification of agriculture is a good approach for reducing the yield gap without exacerbating the current condition of the environmental components, which is a big challenge for agriculture in the modern world. This review provides a summary of the role and approaches of sustainable intensification in agriculture which offer ways to increase crop production and create long-term sustainability in agriculture production. The current demand for food has continued to rise as a result of the world's rapidly increasing population. In order to increase crop/food production, agricultural systems should be intensified by more sustainable practices, as well as by reforming existing production systems/techniques and diversifying them into newer and more profitable enterprises. Despite the heavy use of inputs, farmers have recently been unable to achieve optimal crop yields. The judicious use of agricultural inputs, combined with improved management techniques, is important for advancing sustainable intensification. New scientific techniques in agronomic practices, as well as improved farm mechanization, are helping to boost resource use efficiency in sustainable crop production. The sustainable agricultural intensification is necessary to increase the agricultural productivity under the changing and adverse climatic conditions while maintaining healthy production practices.

scholarly journals Identifying meteorological drivers of extreme impacts: an application to simulated crop yields

2021 ◽  
Vol 12 (1) ◽  
pp. 151-172
Author(s):  
Johannes Vogel ◽  
Pauline Rivoire ◽  
Cristina Deidda ◽  
Leila Rahimi ◽  
Christoph A. Sauter ◽  
...  
Keyword(s):  
United States ◽  
Vapour Pressure ◽  
Crop Yields ◽  
Model Performance ◽  
Vapour Pressure Deficit ◽  
Growing Season ◽  
The United States ◽  
Climate Extreme ◽  
Crop Failure ◽  
Grid Points

Abstract. Compound weather events may lead to extreme impacts that can affect many aspects of society including agriculture. Identifying the underlying mechanisms that cause extreme impacts, such as crop failure, is of crucial importance to improve their understanding and forecasting. In this study, we investigate whether key meteorological drivers of extreme impacts can be identified using the least absolute shrinkage and selection operator (LASSO) in a model environment, a method that allows for automated variable selection and is able to handle collinearity between variables. As an example of an extreme impact, we investigate crop failure using annual wheat yield as simulated by the Agricultural Production Systems sIMulator (APSIM) crop model driven by 1600 years of daily weather data from a global climate model (EC-Earth) under present-day conditions for the Northern Hemisphere. We then apply LASSO logistic regression to determine which weather conditions during the growing season lead to crop failure. We obtain good model performance in central Europe and the eastern half of the United States, while crop failure years in regions in Asia and the western half of the United States are less accurately predicted. Model performance correlates strongly with annual mean and variability of crop yields; that is, model performance is highest in regions with relatively large annual crop yield mean and variability. Overall, for nearly all grid points, the inclusion of temperature, precipitation and vapour pressure deficit is key to predict crop failure. In addition, meteorological predictors during all seasons are required for a good prediction. These results illustrate the omnipresence of compounding effects of both meteorological drivers and different periods of the growing season for creating crop failure events. Especially vapour pressure deficit and climate extreme indicators such as diurnal temperature range and the number of frost days are selected by the statistical model as relevant predictors for crop failure at most grid points, underlining their overarching relevance. We conclude that the LASSO regression model is a useful tool to automatically detect compound drivers of extreme impacts and could be applied to other weather impacts such as wildfires or floods. As the detected relationships are of purely correlative nature, more detailed analyses are required to establish the causal structure between drivers and impacts.

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