eChapters

1. MATURITY INDICES
Maturity indices (right time of harvesting) are quality factors that give clues as to when a product should be harvested to allow marketing flexibility and ensure the attainment of minimum acceptable quality to the user. It also refers to the set of criteria used to determine the stage of maturity for harvesting the horticultural crops. Commodities harvested either pre-mature or too late are more susceptible to postharvest physiological disorders, diseases and have poor shelf life than harvested at right stage of maturity. The pickers/ handlers are trained in methods of identifying produce that is ready for harvest. However, optimum harvesting stages depends upon type of produce and their final use. Horticultural crops may be harvested at two main maturity levels i.e., physiological maturity and commercial or horticultural maturity. Therefore, the proper stage/maturity indices for harvesting of all horticultural crops should be identified for their implementation during harvesting. Horticultural maturity in relation to developmental stages of the plants is depicted in Fig 3.1.
Maturity indices are different for different horticultural crops and are employed to:
1. Ensure sensory quality (flavour, colour, aroma, and texture) and nutritional quality: Harvesting horticultural produce too early (under-developed or immature produce) will result

The horticultural produce includes fruits, vegetables, flowers, plantation crops and spices. However, fruits and vegetables are the most consumed and important commodity among them. Morphologically and physiologically, the fruits and vegetables are highly variable and may come from a root, stem, leaf, immature or fully mature and ripe fruits. They have variable shelf life and require different suitable conditions during marketing.

The horticultural produce includes fruits, vegetables, flowers, plantation crops and spices. However, fruits and vegetables are the most consumed and important commodity among them. Morphologically and physiologically, the fruits and vegetables are highly variable and may come from a root, stem, leaf, immature or fully mature and ripe fruits. They have variable shelf life and require different suitable conditions during marketing. All fresh horticultural crops are high in water content and are subjected to desiccation (wilting, shrivelling) and to mechanical injury. Various authorities have estimated that 20-30% of fresh horticultural produce is lost after harvest and these losses can assume considerable economic and social importance.

Maturity

It is the state of reaching a stage of full or advanced development of tissue of fruits and vegetables, after which it will ripen normally. During the process of maturation, the fruit receives a regular supply of food material from the plant and at maturity, the abscission or corky layer formed at the stem end stops this inflow. Afterwards, the fruit depend on its own reserves, and carbohydrates are dehydrated and sugars start accumulating until the sugar acid ratio formation. In addition to this, typical flavour and characteristic colour also develop. It has been determined that the stage of maturity at the time of picking influence the storage life and quality of fruit, when picked immature like mango develop white patches or air pockets during ripening, thus lacks in in normal brix acid ratio or sugar acid ratio, taste and flavour. On the other hand, if the fruits are harvested over mature or full ripe, then they are easily susceptible to microbial and physiological spoilage and their storage life is considerably reduced. Such fruits continue to show numerous problems during handling, storage and transportation. Therefore, it is necessary or essential to pick up the fruits or vegetables at correct stage of maturity to facilitate proper ripening, distant transportation and to obtain maximum storage life.

Maturity indices and their adoption at harvesting and in post harvest management of fruits provide a information against quality loss, microbial decay and deterioration of external appeal. Fruit harvesting at proper stage of maturity has direct effect on quality and market value of produce. Stage of harvesting also influence the after harvest enzymatic activities of the horticultural produce, which determines the levels of different pigments, sugars, acids and vitamins in fruits, flowers and vegetables. Maturity can be described as the attainment of a particular size, stage after which ripening takes place. However, horticultural maturity is defined as the stage of development when a plant or plant part possess the prerequisites for utilization by consumers for a particular purpose. Cucumbers, lettuce and peppers are harvested at various stages (Horticultural maturity) prior to reaching physiological maturity, or completion of growth phase.

There are many methods to determine produce maturity. The most common is the size of the individual commodity.Some other commonly used crude methods are colour change, Softening of the tissues (fig,sapota) ease of detachment from the stalk (Sapota, annona), shrivelling of fruit stalk (water melon), time elapsed from the date of flowering to picking maturity, sound by tapping jack and water melon when ripe produce hollow and dull sound on tapping but produce metallic sound if unripe etc. Another physical characteristic is the firmness and it is determined with a pressure tester. Firmness is often correlated with chemical changes that occur during ripening. Chemical characteristics include TSS, acidity, sugar, vitamins and pigments. There are certain test which accurately gives the maturity measurements such as use of colour charts (judge colour), penetrometers (firmness), brix: acid ratio etc. Other recent methods viz. thermal conductivity X-rays and NIR have also come in practice to judge the maturity of fruits and vegetables. Some commonly use maturity indices are given below in some of the important fruits.

Horticulture crops contribute significantly for the total agricultural production and productivity. World production of fruits accounted for the total volume of 933 million tonnes (FAO, 2023). India being second largest producer for majority of fruit commodities had a production total reaching 108.34 million tonnes in 2022-2023 from an area of 7.15 million hectares. It accounts for 33 per cent to the agriculture GVA (Gross Value Added) and plays an important role in the Indian economy. India is second largest producer of majority of fruits and vegetables. Diverse agro-climatic zones in the country make it possible to grow almost all varieties of fruits in India. Produced fruits are used for domestic consumption, processing and export purposes. During 2022 23, fresh fruits exports was valued at 6219.46 crores (APEDA, 2023). The fruits grown in India includes domestic fruits and nuts along with the exotic fruits contributing for the food and nutritional security. The growth of these economically important fruits provides scope for maintaining rich germplasm, enhance bio-diversity and maintain ecological balance.

Objectives

1. To study the maturity indices of various spices and condiments.
2. To study the harvesting time and yield of various spices and condiments.

Maturity: A stage of attainment of final state of biological function beyond which growth and development ceases.

Maturity indices: An indication of appropriate stage of harvesting of the produce.

Harvesting: It is deliberate action to separate the plant product from its source of attachment.

Why harvesting at right stage for spices and condiments?

1. To avoid loss of flavour and volatile oils
2. Reduction in yield due to shattering
3. To get the higher yield
4. Recovery of more essential oil
5. Chances of attack of mycotoxigenic and storage pest

Maturity can be defined as the attainment of a particular size or stage after which ripening takes place. It is also called physiological maturity. However,horticultural maturity is defined as the stage of development, when a plant or plant part possesses the prerequisites for utilization by consumers for a particular purpose. Mango, tomato, cucumbers, lettuce, peppers, etc. are harvested at various stages depending on the objective of disposal (horticultural maturity) prior to reaching physiological maturity, or completion of growth phase.

Maturity indices are the most important for deciding the stage of harvesting and to reduce post-harvest losses. The post harvest life of fruits are mainly controlled by maturity. Maturity signs are also called maturity standards or maturity indices. Maturity signs help in judging maturity of fruits and vegetables. There are many methods to determine maturity. The most common is the size and shape of fruit, change in colour, softening of tissues (fig, sapota), ease of detachment from the stalk (sapota, annona), shriveling of fruit stalk (watermelon), drying of nearest tendril (watermelon), days from blooming to picking maturity, sound by tapping jack and watermelon, when ripe produce hollow and dull sound on tapping but produce metallic sound if unripe etc.

Maturity of Cashewnut

Cashew fruit has two parts namely cashew nut (actual fruit) and cashew apple (pseudo fruit). Development of these is not parallel. Cashew nut develops first and the pseudo fruit develops later. It takes 60 days for both the nut and the pseudo fruit to develop completely since anthesis. Development of cashew apple and nut has been studied by number of workers in different cashew varieties (Rao et al., 1962; Augustin and Unnithan, 1981; Mohan Kumar et. al., 1984; Antarkar and Joshi, 1987). According to the report, specific gravity could be considered as physical index of maturity of nut in cashew varieties of V-1, 2, 3, 4 and 5 (Antarkar and Joshi, 1987; Mohan Kumar et al., 1984). In Thailand, the nut reached maximum size in 4 weeks after fruit set, hardened in the subsequent week and declined in size by 10 per cent at harvest (Sumrit Feungehan et al., 1989). Augustin and Unnithan (1981) have reported that the growth of nut is faster during early stage of development than that of fruit. All these reports indicate that the cashew nut develops earlier than cashew apple. Changes in the composition of cashew nut and apple during development have been looked into by various workers. Hariharan et al. (1985) have reported decrease in amino acid content in kernel with increased maturity. Cashew kernel lipid, free amino acids and CNSL have been shown to increase with increased maturity. Similarly, cashew kernel phenols have been shown to decrease with maturity. Changes in the kernel sugars and starch were not uniform (Anon., 1998).

5.1 Introduction

In many problems of economics, we may want to know how small or how large a certain quantity may become. In other words, we may want to know the minimum and maximum values of some functions of variables.

The term ‘optimisation’ may be used in general, both for maximisation and minimisation. The term ‘optimal position’ is often applied to the ‘equilibrium position’ resulting from the balancing of the forces.

Increasing crop productivity while reducing resource consumption is a central objective of modern agriculture. This chapter examines how artificial intelligence can support crop yield improvement through data-driven analysis, prediction, and decision-making. AI models can integrate information from soil, weather, crop growth, remote sensing, IoT sensors, and historical yield records to identify important factors influencing productivity. Machine learning and deep learning approaches can support yield forecasting, crop selection, fertilizer and water optimization, and precision management. The chapter also considers AI-enabled genomic selection, market intelligence, and intelligent farm management. Challenges such as data availability, implementation cost, connectivity, farmer training, and model reliability are discussed alongside future opportunities including edge AI and explainable AI.

A climate-resilient agriculture, which we need urgently, will have to be based on a two-pronged strategy: maximising farm productivity and production during a normal monsoon period, and minimising the adverse impact of unfavourable weather as witnessed during 2009.  Unfortunately, we are yet to develop an anticipatory research and extension programme to minimise damage during unfavourable monsoon periods.  For example, the deficiency in rainfall during the southwest monsoon of 2009 was 23 per cent.  The growth in agriculture and allied sector GDP was minus 0.2.  The highest growth rate in agriculture GDP of 5.2 per cent was observed during 2005-06 when the growth in total GDP was 9.5 per cent.  Had we had a scientific monsoon management strategy, we could have minimised the loss in 2009-10.  Similarly, if we have a strategy for maximising the benefits of a good monsoon, we can hope to achieve at least 5 per cent growth rate during 2010-11 in agriculture and allied sectors.  In parts of China like the Yunnan province, which has experienced 60 per cent less rainfall than normal, there is a move to grow different crops together in the same field, thereby distributing the risk arising from monoculture. It is time to develop a pro-active monsoon management strategy.

Crops treated with pesticides invariably contain small amount of these chemicals and the hazard depends on the amount of pesticide residues that remain on the crop and their toxicity. The amount of residue that may remain on crop or food commodity and environmental commodities depend on the nature of pesticides, good agricultural practice, environmental conditions and adoption of safe waiting periods and other perfect methods of storage. As residues are inevitable by product of pesticide use, hence pesticide residue in food commodities and their entry in to food chain has become major cause of concern all over the world. The plant science industry has a responsibility to assist farmers to produce crops that are acceptable to the food chain and consumers alike.

It is clear that pesticide residues in farm produce should be kept as low as practicable, and eliminated whenever possible through Good Agricultural Practices (GAP). However, the use of pesticides can be regulated to ensure minimum residues on food which can be considered safe to human consumption and environment as a whole.

To regulate pesticide residues to safe levels, a concept was introduced by Joint FAO/WHO Expert Committee on Food Additives (1955) and Codex Alimentarius Commissionwas established in 1964 to implement the Joint FAO/ WHO Food Standard Programmes. The Commission has laid down principles for aiming at the maximum residue limits (Tolerance limits) of pesticide on food commodities. The recommendations are based on:

Abstract

Worldwide trend in fruit crops has shifted to high density or meadow orcharding to manage tree size for desired architecture to allow better light interception and easy in operations such as pruning, pest control and harvesting. The meadow orcharding facilitates increase production as well as quality of fruits. High density planting (HDP) is one of the recent and novel concepts of increasing the productivity without affecting the quality of fruits. The HDP has been successfully demonstrated in fruit crops such as apple, mango, citrus, banana, pineapple and guava. However, for more location specific benefit research must continue on appropriate plant canopy, integrated nutrient management suitable varieties, ageing of orchard and tree replacement. HDP accommodates more number of trees per unit area ranging from 500-10,000 plants/ha depending on the type of fruit crop and the level of density such as medium high density 500-1500 plants/ha, optimum high density 1,500-10,000 plants/ha ultra-high density 10,000-1,00,000 plants/ha. High density orcharding is a highly technical entrepreneurship where nutrient management, irrigation and canopy management practices widely vary from traditional orchards hence growers must have full execution knowledge of this technology in present as well as future perspective. Post harvest, storage and marketing are closely associated with the success of HDP technology. Fruit yield increases 2 to 4 times vertically enhancing income of fruit growers.

Wet sieving procedure separates soil into different size aggregates. However, for comparing the aggregate size distribution among management treatments and soil types, it is convenient to use indices. Mean weight diameter (MWD) and water stable aggregate percentage are some of the common indices used in aggregate stability studies.

Mean Weight Diameter (MWD)

This index was proposed by Van Bavel (1949) and is being used widely. The entire soil sample is passed through an 8 mm sieve prior to analysis and is subjected to wet sieving procedure as described before. The parameter which Van Bavel (1949) called the MWD is equal to the sum of the product of (a) the mean diameter (d ) of each size fraction and (b) the proportion of the total sample weight (w ) occurring in the corresponding size fraction. The summation is carried out over all ‘n’ size fraction including the one that passes through the finest sieve.

Participation means different things to different people. They way participant is defined largely depends upon the context and back ground in which participation is applied. While the Economic Commission for Latin America (1973) considers contribution by the people to public programmes to the complete exclusion of any involvement in the decision making process as participation. Cohem and Uphoff (1977) maintain that participation tools includes the peoples involvement in the entire decision making process. Like Cohem & Uphoff, FAO (1982) emphasizes participation in all the decision making processes but by the people’s organization and through self organized action. Paul (1987) introduces the concept of enhancement of well-being in terms of values cherished by the communities as being the ultimate objective of participation.

We mean sustainable of agriculture as preservation of productivity of land for a long period. This requires deviation from present methods of cultivation. The deviation needs knowledge about ecological process. At present we mean agriculture in association with terms like, high-tech, bio-tech and info-tech. Our traditional farming system or conventional farming system essentially means sustainable agriculture.

Need of an average

Through frequency distribution are the condensed form of raw data, but these are not sufficient for making comparison between two or more data. Therefore further condensation of frequency distribution into a single figure is made. This single f igure is always representative of the frequency distribution and such a figure is known as average.

Measure of Central Tendency

According to Croxten and Cowden “An average is a single value within the range of the data that is used to represent all the values in the series”. A statistical measure used for representing the centre of central value of a set of observations is known as “Measure of Central Tendency”. It is also called as “Measure of f irst order”.

Characteristics of an ideal Measure of Central Tendency

An ideal measure of central tendency should possess the following properties:

1) It should be rigidly defined i.e. it has a fixed and finite value

2) It should be easy to understand 3) It should be easy to calculate

4) Its calculation should be based on all the observations

5) It should be capable for further algebraic treatment

6) It should not be affected by extreme values of the observations

7) It should be least affected by fluctuations of sampling

Dispersion

Measure of central tendency tells about the central position of the series. They do not throw like on the formation of series because in some cases, two series may have a same measure of central tendency but differ in their composition. In order to study the formation, composition, structure and scatteredness of the items of the series, measure of second order are necessary. The measure of second order will give idea about the formation of the series. As the representation of a series on the basis of its measure of central tendency is not sufficient but when a series is represented on the basis of its measure of central tendency as well as its measure of dispersion, then it will give the complete adequate representation of the series. Therefore, it is defined as the extent or degree of which data tend to spread around an average is called the dispersion. It is also known as variability or measure of second order.

Characteristics of an ideal Measure of Dispersion

An ideal measure of dispersion should possess the following properties:

1) It should be rigidly defined i.e. it has a fixed and finite value

2) It should be easy to understand

3) It should be easy to calculate

4) Its calculation should be based on all the observations

5) It should be capable for further algebraic treatment

6) It should not be affected by extreme values of the observations

7) It should be least affected by fluctuations of sampling

Object: Measurement of absorption spectrum of chloroplastic pigments.

Material required: Spectrophotometer, plant leaves, ethanol, electric balance, beaker, test tubes and water.

Temperature influences most plant processes, including photosynthesis, transpiration, respiration, germination, flowering, adaptation and distribution of crops. As temperature increases (up to a point), photosynthesis, transpiration, and respiration increase. When combined with day-length, temperature also affects the change from vegetative (leafy) to reproductive (flowering) growth. Depending on the situation and the specific plant, the effect of temperature can either speed up or slow down this transition.

Temperature is the measure of mean kinetic energy per molecule of the molecules in an object, while the heat is the measure of total kinetic energy of all the molecules of that object. A large object may  have a much lower temperature than a small object and may still have greater heat content by virtue of larger number of molecules in it. Thus heat and temperature are not the same.

Cloud is a visible aggregate of minute water droplets and/or ice particles, or both in the air usually above the general ground level. Clouds are the most important form of suspended water droplets caused by condensation. There is no precipitation without clouds.

11.1. Measuring Instrument

The cloudy hours are measured with the help of eye or sensory parts of the body. No particular instrument is required for cloud amount or cloud cover measurement in the sky.

The most established method for detecting crop water stress remotely is through the measurement of a crop’s surface temperature. The correlation between surface temperature and water stress is based on the assumption that as a crop transpires, the evaporated water cools the leaves below that of air temperature. As the crop becomes water stressed, transpiration will decrease, and thus the leaf temperature will increase. Other factors need to be accounted for in order to get a good measure of actual stress levels, but leaf temperature is one of the most important.

Introduction

All biological reactions in soil are catalyzed by enzymes. Soil enzyme activities are believed to indicate the extent of specific processes in soil and in some cases, can act as indicators of soil fertility. Biological oxidation of organic compounds is generally a dehydrogenation process and there are many dehydrogenases that carry out the following reaction:

XH₂ is an organic compound and is a hydrogen donor and A is a hydrogen acceptor. These systems are integral part of the microorganisms, so dehydrogenase activity can be correlated with active population.

Principle

Measurement of dehydrogenase activity involves determination of Triphenyl formazan (TPF) produced by the reduction of Triphenyl tetrazolium chloride (TTC). TTC is a redox indicator, a yellow coloured water soluble salt which possesses the property of being easily transformed into, methanol soluble formazan (intensely coloured, water insoluble) by reduction. 

Dew acts as a source of moisture for the crop plants. It causes reduction in transpiration rate and saving of soil moisture reserves. Dew fall helps in insect-pest and diseases spread in crop plants.

14.1 Dew and Conditions for Dewfall

The radiational cooling during night causes the moisture to saturate and further cooling results into condensation and depositing this moisture in the form of tiny droplets on the grasses, vegetative and other non-conducting surfaces. This deposition form is known as dew. Clear nights, low wind velocity in the order of 1.0 to 3.0 m/s, presence of moderate to high moisture (RH = 75%) and sufficient radiational cooling are the four necessary and conductive conditions for the occurrence of dew.

Sunshine means incoming solar radiation, which consists of a bundle of rays of different wavelengths. At the top of the atmosphere, the amount of radiant energy received is found to be constant (1.94 cal/cm2/min). The receipt of the radiant energy, which is received on the earth and on crop surface, is influence by the cloudy and sunny or clear sky conditions. The brightness hours of the sunshine are an important parameter, which not only influence microclimate of a place but also the photosynthesis of the crop. The radiant energy of intensity of 0.17 cal/cm²/min or 120 W/m² and above is known to specify the bright sunshine.

The change of state of water form solid or liquid to gaseous form is known as evaporation. It may be defined as the water loss in vapour form from a soil/water surface. The energy used in this process is called as latent heat. The energy of 540 cal/g of water is used in this process. This process plays a major role in the redistribution of thermal energy between the earth and the atmosphere. Water vapour diffuses into the atmosphere from the different natural surfaces like ocean, river, lake, pond, soil and plant etc. It is difficult to measure the evaporation from the natural surfaces. To measure the evaporation from open water surface is easy and is normally in practice. The rate of evaporation is dependent on the size of the measuring surface (Pan) at constant wind speed below saturation point. Therefore a measured surface (Pan) is designed to measure the evaporation.

Evapotranspiration (ET) is the combined loss of water from vegetation and soil. When water is not a limiting factor at a site, the rate of ET is primarily controlled by meteorological factors like solar radiation, temperature, wind and relative humidity. The measurement of ET under natural conditions is of great importance in the water resource management and irrigation planning. Potential evapo-transpiration (PET) is the evaporation from a surface if water was never a limiting factor. PE-can also be calculated using empirical formulae.

It is the actual minimum temperature experienced by the plants near ground surface. The grass minimum temperature is lower than the air temperature at 4 ft level. It is the temperature recorded in open air ground on short turf, with the bulb of the thermometer just in contact with the tips of the blades of grass. It is also described as the temperature at 5.0 cm (2 inches) above ground. It is used during October to March period only when frost occurrence is expected. The readings of the grass minimum thermometer indicate the possibility of ground frosts, which is important information for farmers, gardeners and growers.

Aim

To measure horizontal distance on the level ground using chain

Materials required

Chain

Ranging rods

Chain pins

Field note book

The presence of moisture in atmosphere is termed as humidity and plays an important role in formation of weather system and plant as well as insect-pest growth and development. An abundance of moisture results in a rich natural flora and makes possible a wide choice of crops. Deficiency of moisture, on the other hand, permits only narrow range of crops. Humidity also affects the water requirement and the rate of transpiration. Reduction in transpiration reduces the translocation of food material and uptake of nutrients. High humidity with high temperature favours the outbreak of pest and disease. Moisture stress condition reduces the cell size and shape and ultimately plant growth and yield is reduced. High soil moisture and humidity condition cause failure in establishing stand of legumes and pulses. Excess of soil moisture in earlier growing season may result in more vegetative growth and delayed flowering.

Aim

To measure irrigation water by area-velocity method by using (i) float and (ii) current meter

Apparatus required

Float

Current meter

Theory

The rate of flow of water in open channel can be determined by multiplying the cross sectional area of the flow section at right angles to the direction of flow by the average velocity of water. In area-velocity method, the water can be measured at motion. The water is measured in motion by means of rate of flow or discharge and is expressed in litre per second (lps), litre per minute (lpm), cubic metre per second (m³/s), etc. Litre per second: A continuous flow amounting to 1 litre passing through a point each second. Cubic metre per second: A flow of water equivalent to a stream of 1 m long, 1 m wide and 1 m deep flowing at a velocity of 1 metre per second. In area-velocity method, the velocity of water is measured either by float or current-meter

Aim

To measure the irrigation water by using parshall flume

Construction of Parshall flume

Parshall flume is a water measuring device that can be used to measure water flowing in an open channel and intended primarily for use in irrigation. The flume consists of a converging inlet section, a throat section with straight parallel sides, and a diverging outlet section (Fig.61.1). The floor of the converging section is level with walls which converge in the direction of flow, towards the throat. The throat section constitutes the middle portion of the Parshall flume. The floor of the throat section is dips downward in the direction of flow, but the walls are parallel. The throat width specifies the dimensions of the parshall flume. The diverging outlet section of the flume has a floor which rises in the direction of flow. The walls become further separated in the direction of flow (diverge).The parshall flume can be constructed by G.I. sheet, aluminum sheet, M.S. sheet, brick masonry, reinforced concrete or timber. Flumes made of G.I. or aluminum sheets are easily portable. Brick masonry and concrete flumes are permanently constructed in the channels. Stilling wells should be constructed at the side to take measurements.

Aim

To measure the irrigation water by using orifice

Orifices

An orifice is an opening in a bulk head with closed perimeter usually circular or rectangular cross-section through which water flows. For measurement of water, orifices are fabricated by making an accurate cut of proper size and shape in a mild steel sheet, aluminum plate etc. Proper machining is done to have a sharp edge through which water flows (Fig.60.1).

Free discharge

If the downstream water level is lower than the bottom of the orifice opening, the water jet discharges freely into the air and then it is said to be free discharge. The depth of water on the upstream side of the orifice that causes the flow is called the head. The orifice flow formulae can be applied only when the orifice flows fully.

Aim

To measure the irrigation water by using weirs

a) Weirs

A weir is a notch or opening of some definite shape installed on a channel or a stream through which waterfalls (Fig.59.1). Materials like wood, concrete, mild steel, rigid PVC etc. can be used for construction of a weir. Mainly a cut on a sheet metal is used for fabrication of weirs, to be installed at various locations in a channel. Advantages of weirs are (i) capable of accurately measuring a wide range of flows (ii) easy to construct, portable and adjustable (iii) tends to provide more accurate discharge rating than flumes and orifices.

Aim

To measure irrigation water by volumetric method

Apparatus required

Siphon tube

Stop watch

Measuring bucket

Aim

To measure the irrigation water flowing through a pipe by using Venturimeter

Theory

A venturimeter is a device used to measure the rate of flow of a fluid through a pipe and is often fixed permanently at different sections of the pipeline to know the discharge there. Venturimeter consists of three parts: (i) a short converging part (ii) a throat (iii) a diverging part (Fig.62.1). In the venturimeter, the fluid is accelerated through a converging cone of angle 15-20° and the pressure difference between the upstream side of the cone and the throat is measured, and provides the signal for the rate of flow. Due to the constriction there is an increase in the flow velocity and hence an increase in the kinetic energy. The fluid slows down in a cone with smaller angle (5-7°) where most of the kinetic energy is converted back to pressure energy. Because of the cone and the gradual reduction in the area there is no “vena contracta”. The flow area is at minimum at the throat.

Measurement of water used in irrigation ensures the application of required amount of water in crops. Knowing the rate of flow the adjustment to period of control at gates, etc. can be done to regulate the water at different branches of canals. To get the total control over the supply of water there should have the provision of water measurement at the critical points in irrigation systems.

Units of Measurement

Water is measured at rest or in motion. The water of reservoir, ponds, tanks, etc. at rest is measured in volumetric unit as liter, cubic meter, hectare-meter and hectare-centimeter. Water flowing in rivers, canals, channel, etc. is measured in liter/s, liter per hour, meter per second and hectare-meter per hour or day.

Measurement of water used in irrigation ensures the application of required amount of water in crops. Knowing the rate of flow the adjustment to period of control at gates, etc. can be done to regulate the water at different branches of canals. To get the total control over the supply of water there should have the provision of water measurement at the critical points in irrigation systems.

Units of Measurement

Water is measured at rest or in motion. The water of reservoir, ponds, tanks, etc. at rest is measured in volumetric unit as liter, cubic meter, hectare-meter and hectare-centimeter. Water flowing in rivers, canals, channel, etc. is measured in litre/sec , liter per hour, meter per sec and hectare-meter per hour or day.

Water Quantity and Measurement: The amount of water to be applied and its measurement are crucial aspects of irrigation management. There are various methods and tools used to measure and control the flow of water, including:
1. Parshall flume
2. Orifice
3. Weirs
4. Water meter
5. Float method
6. V-Notch
Methods of Soil Moisture Measurement
The measurement of soil moisture is essential to determine when to irrigate, the amount of water needed, to evaluate evapotranspiration, and to monitor soil matric potential. Soil moisture is measured in two ways: direct and indirect methods.
Direct Methods
1. Gravimetric method: The gravimetric method is a standard method for measuring soil water content directly. It involves collecting soil samples from the field and determining their moist and dry weights. The mass water content is then calculated as the ratio of the weight loss in drying to the dry weight of the soil sample. This method is accurate but time-consuming and requires laboratory equipment.
2. Spirit burning method: The spirit burning method is a direct method for measuring soil moisture in the field. Soil moisture is evaporated by adding alcohol and igniting it. The time taken for the soil to dry is then used to calculate the soil moisture content. This method is quick and easy but can be affected by soil temperature and organic matter content.

Object: Measurement of leaf area by graph paper method.

Material required: leaves, graph paper and pencil or pen.

Leaf area is an important attribute in bio-productivity studies, as it bears an important and direct relationship to photosynthesis and transpiration. Leaf area is also important in determining the percentage of solar radiation intercepted by an individual plant or crop canopy. Photosynthesis centers on individual leaf. However, productivity depends not only on individual leaves but on stand of vegetation and canopy structure. The photosynthetic productivity of a canopy depends on both the amount of leaves present and the configuration of the leaves making up the canopy. Thus, leaf area has direct bearing on plant growth and final yield.

Aim: To know the actual length of a Thomas splint & measurement for an animal.

Procedure

Animal is kept in lateral recumbancy with affected limb upward.

After padding & medical bending of Thomas splint, it is fitted upon the fractured limb.

At the time of measurement, the limb should be kept vertical to body for accurate measurement, otherwise the length of Thomas splint may be shorteror longer if the limb is kept forward or backward respectively.

The ring of the Thomas splint is kept close to the axilla (forelimb), groin (hind limb).

Limb is put downward & Thomas splint is pushed upward keeping both the extension bamboo of Thomas splint in crossed manner, measurement of length of Thomas splint is taken up to the bulb of the heel & mark is recorded.

The excess length is trimmed short (figure-1). Two nicks are made on the distal end for retaining the thread in position.

Both the distal ends are tied together with thread, soft padding is placed at the site where hoof is to be kept & retained in position with bandage (figure-3).

Introduction

The major biogenic gases, which contribute to global warming, are carbon dioxide, methane and nitrous oxide. Out of these, methane is the most important gas because its thermal absorption is 30 times greater than carbon dioxide, though its atmospheric concentration is about 200 times less than carbon dioxide. Atmospheric measurements of greenhouse gases indicate that methane concentration had increased by 1 per cent annually to 1.7 ppm (by volume) during the last decade. The steady increase of atmospheric methane concentration in the past 200 years has attracted much attention.

Flooded rice soils provide an optimum environment for methane production and emission. Flooding a soil creates essential redox potential, anaerobic decomposition of organic matter and stabilizes the soil pH near neutral, thus makes the congenial environment for methane emission.

Rice is the world’s most important food crop

Introduction

The soil microbial biomass is an important component of the soil organic matter that regulates the transformation and storage of nutrients. It is a labile component of the soil organic fraction containing 1 to 3% of the soil carbon and up to 5% of the total soil N. The microbiologically mediated processes affect ecosystem functions associated with nutrient cycling, soil fertility, global C change and soil organic matter turnover. The size and activity of the soil microbial biomass must be assessed to fully understand nutrient flux in managed and natural ecosystems.

Soil microbial biomass estimations are useful in investigations that compare temporal nutrient fluctuations along natural and perturbed gradients. The effect of tillage, crop rotations and soil type on organic carbon and nutrient turnover can be assessed by following nutrient pools and activity associated with the soil microbial biomass.

Measurement of soil aeration

Oxygen Diffusion Rate (ODR) - the rate at which O₂ in soil air is replenished. ODR decreases with soil depth.

Measurement of ODR in soil

Lemon and Erickson (1952) devised a method for measuring oxygen diffusion in the soil system with the help of platinum micro electrode

Principle

When a certain potential is applied across the platinum electrode and a reference electrode inserted in the soil, oxygen is reduced at the platinum surface. The electric current flowing between two electrodes is proportional to the rate of oxygen reduction. The later, in turn, is related to the rate of oxygen diffusion to the electrode. The oxygen diffusion rate (ODR) is calculated from the measured electric current with the following equation.