1) Nutrient uptake models can be empirical or mechanistic, with mechanistic models being more reliable for extrapolation.
2) Major mechanistic nutrient uptake models are based on the diffusion and mass flow of nutrients from soil to root surfaces.
3) Models have incorporated Michaelis-Menten kinetics to describe crop uptake and considered effects of root properties, soil properties, and competition between roots.
4) Computerized models now simulate nutrient uptake dynamics over time and between competing root systems.
Maize (Zea mays L.) and wheat [Triticum aestivum (L.) emend. Fiori & Paol] is the third and second most important cereal crop of India, respectively. Maize–wheat system is the third dominant cropping system of India covering 1.8 mha with 2.3% contribution in food grain production (Jat et al., 2013).
Interactions between nutrients in plants occur when the supply of one nutrient affects the absorption, distribution and functions of another nutrient. Generally P and Zn interact negatively, which depends upon a number of physico-chemical properties of soil. Antagonistic P×Zn interaction has been subject of intensive research in several countries and has been thoroughly reviewed. Although some positive interactions of P and Zn are also reported (Shivay, 2013).
The maximum available P and Zn content in the soil was recorded with super-optimal dose (150% NPK) and optimal dose (100% NPK) along with Zn, respectively (Verma et al., 2012). Zinc and P application has antagonistic effect on each other with respect to their concentration and absorption by wheat and maize (Verma and Minhas, 1987). The three Bacillus aryabhattai strains (MDSR7, MDSR11 and MDSR14) were consistent in enhancement of root and shoot dry weight and zinc uptake in wheat (Ramesh et al., 2014).
Management of P×Zn interaction is a challenging task in the era of sustainable food and nutritional security. Use of efficient varieties and application of inorganic P and Zn fertilizer in conjunction with bio-inoculants can increase the crop yield and efficiency of added fertilizers to save precious input.
Potassium- Forms,Equilibrium in soils and its agricultural significance ,mech...Vaishali Sharma
The slide is conserned with the potassium fertilisers apllied in the soils. When the fertiliser applied in higher amount then it is avail in different form for plant uptake and there exist a equilibrium in soils and it has many agricultural significance and the slide also deal with brief on the mechanism of potassium fixation in the soil.
Maize (Zea mays L.) and wheat [Triticum aestivum (L.) emend. Fiori & Paol] is the third and second most important cereal crop of India, respectively. Maize–wheat system is the third dominant cropping system of India covering 1.8 mha with 2.3% contribution in food grain production (Jat et al., 2013).
Interactions between nutrients in plants occur when the supply of one nutrient affects the absorption, distribution and functions of another nutrient. Generally P and Zn interact negatively, which depends upon a number of physico-chemical properties of soil. Antagonistic P×Zn interaction has been subject of intensive research in several countries and has been thoroughly reviewed. Although some positive interactions of P and Zn are also reported (Shivay, 2013).
The maximum available P and Zn content in the soil was recorded with super-optimal dose (150% NPK) and optimal dose (100% NPK) along with Zn, respectively (Verma et al., 2012). Zinc and P application has antagonistic effect on each other with respect to their concentration and absorption by wheat and maize (Verma and Minhas, 1987). The three Bacillus aryabhattai strains (MDSR7, MDSR11 and MDSR14) were consistent in enhancement of root and shoot dry weight and zinc uptake in wheat (Ramesh et al., 2014).
Management of P×Zn interaction is a challenging task in the era of sustainable food and nutritional security. Use of efficient varieties and application of inorganic P and Zn fertilizer in conjunction with bio-inoculants can increase the crop yield and efficiency of added fertilizers to save precious input.
Potassium- Forms,Equilibrium in soils and its agricultural significance ,mech...Vaishali Sharma
The slide is conserned with the potassium fertilisers apllied in the soils. When the fertiliser applied in higher amount then it is avail in different form for plant uptake and there exist a equilibrium in soils and it has many agricultural significance and the slide also deal with brief on the mechanism of potassium fixation in the soil.
This presentation was presented during the Plenary 1, Opening Ceremony of the Global Symposium on Soil Organic Carbon that took place in Rome 21-23 March 2017. The presentation was made by Mr. Luca Montanarella from EU Commission’s Joint Research Centre, in FAO Hq, Rome
Substances containing carbon are organic matter.
Soil organic matter consists of decomposing plant and animal residues.
It also includes substances of organic origin either leaving or dead.
This presentation was presented during the Plenary 1, Opening Ceremony of the Global Symposium on Soil Organic Carbon that took place in Rome 21-23 March 2017. The presentation was made by Mr. Luca Montanarella from EU Commission’s Joint Research Centre, in FAO Hq, Rome
Substances containing carbon are organic matter.
Soil organic matter consists of decomposing plant and animal residues.
It also includes substances of organic origin either leaving or dead.
Diversity of Soil Fauna and Ecosystem Function tariqulmasud12
Soils are natural resources of utmost. Importance for a number of ecosystem and biosphere processes such as plant production, cycling of organic matter and nutrients, storage of C and water, and release of nitrous oxides, CO2 and methane. Soil degradation, through various processes, is a matter of great concern, since their integrity is absolutely critical to increasing food production (FAO, 1995), and regulating atmospheric fluxes of greenhouse gases (Jenkinson, 199 1 ; Wallace, 1994).
This research makes use of the remote sensing, simulation modeling and field observations to assess the non-point source pollution load of a Himalayan lake from its catchment.
HyeJin Kim and Simon Smart - The biodiversity nexus across multiple drivers: ...OECD Environment
This OECD technical workshop will bring together leading experts on economic, biophysical, and integrated assessment modelling of the interactions between climate change, biodiversity loss, and pollution. The workshop will take stock of ongoing modelling efforts to develop quantitative pathways to study the drivers and impacts of the triple planetary crisis, and the policies to address it. The aim is to identify robust modelling approaches to inform the work for the upcoming OECD Environmental Outlook.
Jatropha-based alley cropping system’s contribution to carbon sequestrationInnspub Net
The study was conducted to evaluate the total carbon stocks sequestered in a Jatropha – based alley cropping system treated with varying fertilizer applications. The study was laid out in Randomized Complete Block Design with three replications. The alley was planted with corn in two seasons Treatments include control (no fertilizer), organic fertilizer and inorganic fertilizer applied to the alley crops. Findings showed that the treatments with fertilizer applications had higher carbon stock in the jatropha hedges. The carbon content of the corn stover was also higher in organic and inorganic fertilizer-applied treatments. However, highest soil carbon content was shown in treatments applied with organic fertilizer (4.28 Ton ha-1). The inorganic fertilizer treatment had the lowest soil carbon content with a mean of 4.28 Ton ha-1. In terms of total carbon stock of the entire jatropha-based alley cropping system, there was a significant difference among treatments with organic fertilizer application having the highest mean of 7.79 Ton ha-1 while the inorganic treated plots had 6.53 Ton ha-1. The no fertilizer treatment had the least carbon stocks with 6.53 Ton ha-1. This recent study revealed that the jatropha-based alley cropping system is a potential land-use for carbon sequestration. This farming system needs to be promoted in upland areas to function not only as soil and water conservation measures but also as a possible remedy for global warming. Get the Abstract and full articles at: http://www.innspub.net/ijaar/jatropha-based-alley-cropping-systems-contribution-to-carbon-sequestration/
This is the Honours presentation of Patrick Hayes. It describes his work on leaf nutrient concentration and resorption along the 2-million year Jurien Bay dune chronosequence. Patty gave an excellent talk!
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
2. MODELS
It is “an assembly of concepts in the form of
a mathematical equation that portrays
understanding of a natural phenomenon.”
3. Emprical models – statistical means
and regression- black box models
Mechanistic models- biophysical,
biochemical and physiological
mechanisms
TYPES
4. NUTRIENT UPTAKE MODELS
• Soil nutrient transformation models emphasize on soil
properties.
• Crop uptake models emphaize on plant characters
especially on root characters and also soil characters.
• Models are formed for (i) identifying the process which
describe nutrient uptake and (ii) evaluating quantitatively
the effect of different parameters of nutrient uptake.
5. • Extrapolation of a verified mechanistic model is more
reliable than that of an empirical model(Claassen and
Steingrobe, 1999).
• The typical mechanistic nutrient uptake model describes
the supply of nutrients from bulk soil to root surfaces, root
growth and morphology, and root uptake kinetics (Barber,
1995).
6. MECHANISTIC MODELS
Steady state models
• Flow of nutrients through a soil- steady state
• Soil – volume element conducting nutrient flow
• Neither a sink nor a source of nutrients
• based on diffusion theory
Transient models
• either a sink or source influencing / modifying its flux
(time)
• describes the dynamic process of nutrient uptake & the
concomitant changes in the ion concentration &
distribution in the rhizosphere.
8. Interception is used to describe the uptake of soil nutrients at the
root interface when soil volume is displaced by root volume
(Barber 1995).
Although conditions in the rhizosphere are sometimes different
from those in the bulk soil (Marschner 1995), the contribution of
interception to nutrient uptake is negligible for most nutrients
(Barber 1995).
Therefore, only mass flow and diffusion are considered to be
responsible for movement of nutrients to the root surface in
mechanistic modeling.
However, Tinker and Nye (2000) consider the concept of
interception to be somewhat arbitrary and argued that it can be
included in the diffusion component.
9. MASS FLOW
Mass flow is the convective transport of nutrients through the
soil to the root surface by water flow as a result of transpiration
(Barber, 1995).
The relative contribution of mass flow to nutrient uptake
depends on the nutrient, plant species, plant age, and time of
day (Marschner,1995).
For example calcium and magnesium supplied to plants by
mass flow is significant, but its contribution to potassium
supply is negligible (Marschner, 1995).
The influx by mass flow (FM) can be calculated by
where v is the mean water flux in soil driven by transpiration,
and CL is the nutrient concentration in the soil solution.
10. DIFFUSION
Diffusion is the movement of nutrients from areas of high
concentration to those of low concentration (Barber
1995).
It is the main mechanism for at least phosphorus and
potassium movement in the soil to plant roots
(Marschner 1995).
A depletion zone is produced when the concentration of
nutrient is lowered near the root surface due to root
absorption (Jungk and Claassen 1997). Diffusive flux FD
can be described by Fick’s first law,
where D is the diffusion coefficient of the nutrient in soil,
C is the nutrient concentration in soil solution, and x is
the distance.
11. SIMULTANEOUS MASS FLOW AND DIFFUSION
Mass flow and diffusion occur simultaneously to supply
nutrients to plant roots and cannot be treated as separate
processes.
Nye and Spiers (1964) presented a partial differential
equation to describe simultaneous mass flow and
diffusion, and this equation became the foundation of the
most mechanistic nutrient uptake models.
12.
13. The Barber-Cushman model is largely based on the work
by Nye and Marriot (1969).
Nye and Marriot (1969) revised the continuity equation
proposed by Nye and Spiers (1964) to describe the flux
of nutrient in the soil to the root surface with the nutrient
concentration in soil solution (CL)
Nye and Marriot (1969) defined boundary conditions and
solved this equation numerically.
15. NYE AND TINKER MODEL
Nye and Tinker, 1977
The uptake of nutrient per unit length (U) is given by,
U= 2πrαC1
r = radius of the root
α = root absorbing power
C1= ion concentration at the root surface
16. Summarizing the work by Claassen and Barber
(1976) and Cushman (1979), Barber and Cushman
(1981) suggested new boundary conditions to
include inter-root competition for nutrients.
The new boundary conditions incorporated inter-
root competition as well as Michaelis-Menten
kinetics.
When solved numerically, the enhanced
mechanistic model evolved into Barber-Cushman
model.
17.
18. Crop uptake is assumed to follow Michaelis-menten
relationship between concentration and flux.
In 1983, Itoh and Barber developed a submodel to
the Barber-Cushman model to include nutrient
uptake by root hairs.
In 1986 Claassen et al. published NST 1.0 model.
In 1987 Oates and Barber published NUTRIENT
UPTAKE model.
Both were based on the Barber-Cushman model.
19. MICHAELIS- MENTEN KINETICS
In=(Imax×Cla)/(Km+ Cla)
Where,
In = Rate of ion uptake
Imax = maximum rate of ion uptake when concentration is
not limiting
Cla = concentration of nutrient ion in soil solution at the
root surface
Km = Michaelis – menten constant which represents a
concentration of nutrient ion in soil solution when In=Imax/2.
20. COMPUTERIZED MODELS
Based on Nye and Tinker model, Smethurst and Comerford
(1993b) developed a computer model, COMP8 (Competition
model version 8), which was able to calculate nutrient uptake
between two competing and contrasting root systems.
SSAND was a revision and expansion of COMP8 by Comerford
et al. (2006).
Its main improvements lie in the functions of predicting nutrient
uptake as influenced by mycorrhizae and simulation of
fertilization effects (Comerford et al. 2006).
21. Based on COMP8 and an earlier version of
SSAND, another steady state model, PCATS was
developed to simulate nutrient uptake by a single
species by Smethurst et al. (2004).
For transient models –NST 1.0, NST 3.0.
22. NYE AND TINKER, 2000
where b is the soil buffer power,
hence c = bc is the total amount of solute bound to the
soil particles;
θ is the volumetric soil water content,
thus is the overall amount of solute per unit volume of soil;
D is the solute diffusivity in water;
f is the soil impedance factor,
Dfθ is the effective diffusion coefficient for the solute in
the soil; and v is the water flux in the soil.
23. MODELLING CROP N UPTAKE
Benbi, Prihar and Cheema (1991) – used mass flow
approach & predicted N uptake for wheat matched with
measured N uptake (wet treatments).
In dry moisture regime other process of N uptake like
diffusion & root interception should be used.
24. BASED ON CROP DEMAND
Several models - driven by demand from the plant.
They calculate N demand for growth rates & concentration of N
required.
Whitmore and Addiscott (1987) – computed demand using a
simple variant of the logistic function to compute the pattern of
N uptake (Y), with thermal time (x):
Y=(A-1/X + e-kx )-n
A - maximum of Y, n - shape factor, k - rate constant.
25. • Tillotson and Wagenet (1982) and Hutson and Wagenet
(1992) – modelled N uptake – based on Nye and Tinker
model.
• Warncke and Barber (1973) – value of α to be estabilished
for different soils, crops and species under a range of
concentrations.
• De Willigen, 1991 – more complex models give better
simulations than simpler ones.
28. M&M MODEL
Satisfactorily describes P uptake flux (Fp, mol cm-1 root
h-1 ) as a function of P concentration in a well-stirred
solution (Cpb mol l-1 ).
Fp = Fp max * Cpa /(Km +Cpa )
Fp max and Km denote the maximum Fp and Cpa at
which Fp = 0.5*Fmax .
P uptake models
Plant roots have a major influence on P dynamics in
the soil.
29. A= (b/a) w/2πDp
a,b = midway distance between root and root radius
Dp = diffusion co-efficient
B = Fpmax /W
W = solution velocity towards the root
Bar and Yosef (1999)
30. K concentration in
plant
K in soil
solution &
exchangea
ble
K flux to
roots by
mass flow &
diffusion
from soil
Root
parameters
Plant dry
biomass Fixed K
Weather parameters
Pottasium
fertilizers
Multi- Parametric model for K uptake
31. S UPTAKE
Mc Caskill and Blair (1988) have developed a pseudo-
mechanistic computer simulation model for predicting
perennial pasture growth and S uptake.
But not verified.
Later Heng (1991) and Phimsarn(1991), developed
simple models of pasture S uptake using relationship
between actual daily ET(AET), average root density in
the soil profile, soil solution S levels, sulphate buffering
capacities.
32. MICRONUTRIENTS
Mathematical models of micro-nutrient uptake by
plants have been based on models designed for
uptake of major nutrients.
This poses a number of problems, as the behaviour
of micro-nutrients in the rhizosphere is different,
particularly with respect to interactions between
solid and solution compartments.
There is no standard procedure for the
measurement of soil parameters that affect the
supply of micro-nutrient from the soil.
33. DPUM
Dynamic Plant Uptake Model
DGT (Diffusive Gradient in Thin-flims) tecnique is
used.