the ways of measuring productivity

1. Definition:

Productivity refers to rate at which energy is accumulated by green seed in unit time in the form of organic substance you can use as food.

2. Types of Output:

Productivity involves four successive

Primary productivity

Gross primary production

Net Principal Production

2. 1 Key Productivity:

The rate at which glowing energy is stored by photosynthetic activity of renewable crops and algae in the form of organic chemical is termed as primary productivity, since it is the first & most basic form of energy stored in the ecosystem.

2. 2 Gross Major Production (GPP)

The total photosynthesis that is all the sun's energy that is assimilated is named gross primary production or GPP. It includes the organic matter used up in respiration during the measurement period. It is also called total assimilation.

2. 3 Net Primary Development (NPP)

Energy remaining after respiration and stored as organic matter over measurement is known as net primary production. It is also called visible photosynthesis. Net production is the energy available to the heterotrophic components of the ecosystem.

A portion of net primary production can be used by plants for expansion the build-up components such as stem and leave and a portion go to storage area organic mixture stored for future expansion and other functions.

The movement of energy during key production can be expressed by the method.

Gross primary creation (GPP) =net primary production (NPP) + respiration (R)

3. Factors influencing production:

The production efficiency of vegetation depends after factors such as light depth the quantum efficiency of light the leaf design on the plant life the leaf area index and the sort the seed whether C-3 or C-4. The environment factors that help promote online output include warm temperatures greater rainfall moving water that holds additional nutrition in natural ecosystem and irrigation application of fertilizers and control of pest in agricultural plants. Swamps and marshes present at the user interface of land and water have net productivity ranging from 900 to 3300 g/m2/yr.

4. Ways of Measuring Output:

Productivity is usually assessed as the speed at which energy or biomass is produced per product area per device time. This rate is expressed in such conditions as kilocalories per square per year (kcal/m2/yr) a assessed or energy or germs per square meter per yr a way of measuring biomass. Various techniques used to calculate primary efficiency are

Light and Deep Bottle Method

Radioactive Tracer Method

Chlorophyll Concentration

Carbon Dioxide Flux

Harvest Analysis

Dimension Analysis

4. 1 Light and Deep Bottle Method:

This method is utilized to measure most important productivity in an aquatic ecosystem like a pond. It is based after the assumption that the quantity of air produced is proportional to gross production because one molecule of oxygen is produced for each and every atom of carbon fixed. Samples of water from different depths are located in paired containers. One of the paired containers is protected with dark-colored tape or aluminium foil to exclude light and other is retained clear to admit light and allow photosynthesis. The air attention of the bottles depends upon Winkles method. The containers are suspended to the same depth from where examples were collected by using string. After a day the bottles are removed their air concentration is determined and compared with the concentration at the beginning. The decrease of oxygen in the dark bottle indicates the quantity of respiration by producers and consumers where the oxygen change in the light container reflects the web result of oxygen used by respiration and oxygen produced. Adding respiration and creation together or subtracting final oxygen concentration in the dark bottle from that in the light containers give an estimation of gross productivity for 24 hours. This technique has its problems. A number of the respiration related to phytoplankton may be bacterial. The phytoplankton population may increase in the bottle during the experimental time however, not in dark container. Also the task is based on the assumption that respiration in the dark is equivalent to in the light.

4. 2 Radioactive Tracer Method:

It is one of the very most useful and delicate method beneficial to estimate primary production in an aquatic ecosystem especially in lakes and oceans. It is based upon way of measuring of 14CO2 uptake. The technique will involve addition of radioactive carbon as carbonate to a sample of water in clear and unpredictable carbon are assimilated into glucose and become area of the protoplasm of phytoplankton. The plankton material is taken off the water cleaned dried and place in a keeping track of chamber to determine the degree of radioactivity. The radioactive matters are used to calculate the amount of carbon dioxide fix in photosynthesis using the photosynthetic formula. The estimate is based on the assumption that of radioactive carbon is proportional to that of secure carbon. However in practice these might not be proportional therefore a modification factor for 14C adsorption in dark bottle is required.

The approach has its deficiencies. It generally does not discriminate between respiration of phytoplankton and bacteria the uptake and release of 14C by bacterias and zooplankton and the capabilities of different types of phytoplankton to make use of available light.

4. 3 Chlorophyll Attentiveness:

This method is based upon estimation of developer from chlorophyll concentration and light intensity through this inflatable water column. The approach improved from the finding by herb physiologist that a close relationship is present between chlorophyll concentration and photosynthesis at any given light intensity. In case the assimilation percentage and the available light are known gross creation can be believed by the extracting pigments and then calculating the chlorophyll focus with a spectrophotometer. The technique was first to used to estimate primary productivity in large normal water body such as sea but later put on terrestrial ecosystem as well as. This technique involves the determination of chlorophyll details of phytoplankton in confirmed volume of drinking water. Because all vegetable need chlorophyll to carry on photosynthesis the quantity of chlorophyll in confirmed amount of water is a direct measure of the full total biomass or ranking crop of phytoplankton it contains. The chlorophyll is extracted chemically and the amount of chlorophyll is assessed. The deeper the colour the higher is the attentiveness of the chlorophyll and for that reason phytoplankton biomass.

The approach has a problem that chlorophyll focus varies with phytoplankton varieties and even within the cells of types. Further extraction technique may alter the chlorophyll.

4. 4 Carbon Dioxide Flux:

It is one of the most useful options for estimating primary production in terrestrial ecosystems. It can help calculating both gross and net primary production. It involves way of measuring of the uptake of skin tightening and in photosynthesis and its own release in respiration. In this method a simple of community which may be twig and its leaves a section of any tree stem the ground cover and land surface or perhaps a portion of the full total community such as an on site test of grassland is enclosed in a cheap tent. Air is drawn through the enclosure and the skin tightening and concentration in incoming air and outgoing air is measured with an infrared gas analyzer or by absorption on a KOH column. The assumption is the fact any carbon dioxide taken off the incoming air during the day has been contained into organic subject. Therefore the degree skin tightening and in the enclosure is equivalent to photosynthesis minus respiration. A similar sample may be enclosed in dark enclosure. The amount of carbon dioxide is produce at night handbag is a measure of respiration when photosynthesis ceases. The quantity of carbon in the light and dark enclosure added together estimates gross creation.

4. 5 Harvest Examination (Standing Crop Method):

Harvest method is trusted to calculate in terrestrial ecosystem. It is most readily useful for estimating the production of cultivated land range and communities of annual vegetation were production starts from zero at seedling or planting time becomes maximum at harvest and is also subject to minimal use by consumers.

The technique will involve taking away vegetation at regular intervals and drying the examples to a frequent weight. To acquire n accurate estimation the creation of place biomass must be sampled throughout the growing season and the contribution of every types must be determined. Different species of plant life reach their peak production at different times through the growing season. The difference in position crop biomass between harvests times expressed as bacteria per square meter per unit time provides an estimate of world wide web primary productivity. Caloric value of the material can be motivated through use of the calorimeter and biomass can be converted to calories. Net principal efficiency is then portrayed as kilocalories per square meter per season.

Harvest method provides information about above surface output usually because low earth productivity requires the examples of root biomass which is difficult at best. Although root base of some total annual and crops flower may be removed from the soil the task become more difficult with turf and herbaceous kinds and much more so with forest trees.

4. 6. Dimensions Analysis:

Because seed of different age, size and types make up the forest community altered harvest technique called dimension analysis can be used by ecologist. This methods help to estimate located crop and efficiency from less extensive sampling. Dimension evaluation involves the measurement of light, diameter or breasts height and diameter development and age depends upon growth ring analysis. Total weight both fresh and dried of leaves and branches as well as the weight of also decided. Often the roots are excavated and weighted. In the same way biomass of ground vegetation litter show up is also identified. Net annual creation of hardwood, bark, leaves, twigs, origins and blossom is calculated. Each one of these information are being used to calculate production of trees and shrubs and other vegetation in a sample unit. After sizing analysis the position crop can be predicated by using data such as (diameter) 2 x level x and gross annual productivity by calculating current wood growth.

5. Overview:

Plants use part of total energy fixed by photosynthesis as maintenance energy. The remainder can be used for new seed biomass and reproduction which is food for herbivores. The amount distribution and the rate of turnover of biomass determine many important characteristics of the community physiognomy variety of herbivores and activity of decomposers. These relationships are constrained by the efficiency which plant absorb light incorporate assimilated energy into photosynthate and convert photosynthate into biomass. Productivity is assessed by several means. (a) Deciding the speed of photosynthesis and respiration (b) estimating changes in biomass over time, (c) Correlating biomass with an easily measured adjustable to estimate position crop, (d) Usage of computer models to determine productivity over extensive spatial scales and forecast reaction to changing environmental conditions. Efficiency in terrestrial ecosystem is influenced by numerous factors: skin tightening and, light, temperature, wetness, nutrients, and garden soil texture. The most fruitful ecosystems are people that have optimal degrees of such factors, finally to maximize photosynthesis. These factors exert their impact all together and interactively often doing so in a non equilibrium manner.

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