eChapters

Introduction
Potato (Solanum tuberosum L.) is one of the most important tuberous, starchy and versatile food crop belongs to family Solanaceae. In India potato is grown in an area of 2.07 Mha with a production of 48 MT and a productivity of 23.19 MT/ha. The potato producing major states in India are Uttar Pradesh, West Bengal, Bihar, Madhya Pradesh, Gujarat and Karnataka. In Karnataka, the crop is grown in an area of 44,160 ha with an annual production of 5,89,120 MT and productivity of 13.34 t/ha (Anonymous, 2014). Further in Karnataka Potato is mainly grown in Hassan, Belgaum, Dharwad, Chikkaballapur and Kolar districts. Hassan district alone contributes more than 41 per cent of potato production in the state (Bhajantri 2011). Basically potato prefers relatively low temperature during early growth and cool weather during tuber development. It requires 25°C temperature at the time of sprouting, 20°C for vegetative growth and 17 to 20°C for tuber development. ARC saplings are mainly used for seed tuber production at a quicker rate. Farmers can produce zero generation seed tubers from ARC saplings without any shipping costs involved. In this regard KVK, Hassan after knowing the existence of innovative ARC sapling technology from the International Center for Potato (CIP), German innovation center (GIZ/GIC) Bengaluru, Krishi Vigyan Kendra, Kandali, Hassan procured tissue culture bottles/mother culture from CPRI, Shimla Himachala Pradesh through CIP, GIZ/GIC Bengaluru. By using the mother culture KVK Hassan has produced approximately two lakhs ARC saplings with existing facility and conducted the field evaluation studies on “Performance and evaluation of Apical Rooted Potato saplings in Hassan district”.
About the Technologies Addressed
The ICAR-KVK, Hassan has introduced two technologies in potato during last decade to improve the yield and to reduce the cost of production, namely, Apical Rooted Cuttings (ARC) for quality seed tuber production and Mechanization in Potato to reduce the labour requirement and drudgery. The ARC is a technology where small portion of disease free mother tuber is collected and multiplied under aseptic conditions (Tissue culture) in a growing media to produce new and healthy plantlets. These plantlets are used as mother

Introduction 
University of Agricultural Sciences, Dharwad is one of the premier agriculture Universities in India has made its remarkable journey in the field of Teaching/ Research / Extension since its inception, UAS, Dharwad has got six Krishi Vigyan Kendras sponsored by Indian Council of Agricultural Research. Which have adopted various outreach methodologies for the farming community. Apart from conventional methods of technology transfer i.e., technologies in pipeline (farm trails) conducted in farmers fields for their acceptance, front line demonstration, on farm testing, PRA, diagnostic field visits etc. KVKs have employed various techniques making use of ICT which have proved to be effective in enhancing the productivity of farms (Medhi et al., 2017), reaching farmers quickly and effectively. The present paper is a compilation of innovative methodologies adopted by KVKs under UAS Dharwad during last five years. As it is mandate for all the KVKs to prepare action plan before the onset of every year during March-April, vigorous exercises are done by KVKs to prioritize the problems faced by farmers in the particular district. These problems are planned to tackle the location specific technologies developed in that zone. If the technologies under FLD banner are not available in particular technologies developed elsewhere in NARS are borrowed and tested for both its sustainability under that agro-ecological system. During this process of prioritizing the problems, implementation and monitoring, KVK adopt various methods given as discussed below.

Introduction 
The mandate of the University under section 30 of the Act of 1963 is for establishment of Extension services for the purposes of under taking extension programs, dissemination of information for solving of problems relating to agriculture and domestic fields, developing the interests of youth in agriculture etc., The first extension service of APAU popularly known as District Extension Education Programmes were introduced in 1967 in Hyderabad district and were subsequently extended to Chittoor(1968)and Guntur (1970) districts. National Demonstrations Scheme (NDS) was established during 1970-71 in the University in four locations. In commemoration of the Golden Jubilee Year of ICAR, a Lab to Land Programme was launched by the APAU in June,1979. In order to improve the productivity of pulses and oilseeds in different regions of the state, two extension education centres were sanctioned by the ICAR at Ananthapur and Rastakuntubai which started functioning from December,1980 and December,1981 respectively. Reorganization of the University Extension work followed the reorganization of research activities of the APAU and implementation of Training and Visit System by the Department of Agriculture to streamline the setup of the field extension program of the University during 1982. To optimize the utilization of available extension resources, the resourcess of District Extension Education programs, extension services around research stations and NATP were integrated and reorganized to form six Extension Education Units. The extension activities of these units were entrusted with the respective Associate Directors of RARS for integrating research and action activities. The Associate directors of Research in turn were made responsible to the Director of Extension. The Extension Education Units conducted different extension activities like organization of field trials for testing new technologies for their feasibility including minikit trials of pre-released varieties to get feedback to the scientists, introduction of new cropping patterns, demonstration of latest technologies through early demonstrations including educational activities like organization of Kisan Melas training programs for the developmental

Introduction
Three districts of South Gujarat i.e., Surat, Navsari and Valsad are front-runners in horticulture cultivation. These are also part of an agri-export zone for fruits and vegetables. But, the life of these fruit- farmers was made miserable by tiny fruit fly which is a major pest of mango, sapota and cucurbits. Intensity of damage recorded was as high as over 30 per cent in mango and sapota, and between 20-40 per cent in cucurbitaceous vegetables. Fruit flies cause heavy damage in terms of quality and quantity to the farmers every year. Insecticidal sprays, control infestation little bit, but they are not only uneconomical but they leave residual effect much above tolerance limit, adversely affecting the prospects of export of such fruits and vegetables. Fruit flies are a modern-day pestilence which ravage production. These flies, moreover, are good fliers and therefore their spread is extensive. Hence, area wide adoption of management strategy is required. Male Annihilation Technique (MAT), an Integrated Pest Management Technique (IPM), which uses sexual lures to capture males of fruit flies and kill them, is the only way to control growth and spread of fruit flies. This however, requires a community approach for implementation. Navsari Agricultural University designed, developed and commercialized an eco-friendly, economical and easily adoptable fruit fly trap popularly known as “Nauroji-Stonehouse Fruit Fly Trap”. The trap uses Methyl Eugenol and Cue lure as par pheromones well-known for fruit flies. In this trap, plywood blocks are soaked in the solution of lures + solvent + insecticide. Such traps remain effective for 5 to 6 months, which cover the entire fruiting period in mangos, sapota as well as cucurbitaceous vegetables and no recharge is necessary. It is eco- friendly, economical and easily adoptable. It was decided to adopt this technology and spread it in the Surat- Navsari- Valsad belt for controlling and managing the fruit fly problem. It was also recognized that wide area adoption would help in developing this zone as a Pest Free Area (PFA). The project was taken up under RKVY.
About the Technology Addressed and Extension Management Practices
Nauroji-Stonehouse Fruits Fly Traps are prepared in food quality Testing Laboratory, NAU Navsari. Six talukas viz, Gandevi, Chikhali, Valsad, Pardi, Dharampur and Kaprada of Navsari and Valsad districts were selected for the purpose. A block of orchards in each village in each Taluka was selected for first year implementation. Other blocks were selected during the following years.

Introduction 
The Pleurotus species, belongs of the basidiomycetes class, are typically grown on non-composted lignocellulose substrates and have a shorter growth cycle compared to other types of mushrooms (Bellettini et al., 2018). These are shell-like fruiting bodies commonly known as “oyster mushroom” and also referred as “Dhingri mushroom” in India. The fanor spatula-shaped fruit body can be found in various colours depending on the species, including white, pink, yellow, grey, and blue (Verma et al., 2023). Their cultivation is popular due to the simple and low-cost methods. These mushrooms are highly favored not only for their taste, flavor, and pleasing texture but also for their nutritional and medicinal benefits (Sharma and Khanna 2019, Sarita et al., 2023). Pleurotus sp. are found naturally in both temperate and tropical regions across the globe which are cultivated more widely around the world due to their adaptable nature (Badshah et al., 2021). Despite their potential, India’s mushroom production has declined significantly, from 487 million MT in 2017 to 314.84 million MT in 2023 (Anonymous, 2023). Mushroom farming in Gujarat presents several opportunities due to various factors such as favorable climatic conditions, easy availability of raw material increasing market demand and supportive government initiatives. In India, rice straw is 80 Innovations of University Extension in Indian Agriculture mainly used as substrate for large scale mushroom production (Kundu et al., 2022). But, cultivation and consumption of mushroom were limited due to lack of awareness about the health benefits of this high valued food. However, by the efforts of KVKs under Agricultural Universities through the trainings and awareness programs, mushroom cultivation becomes popular among the people of Gujarat particularly in rural areas. Entrepreneurs and farmers can tap into this growing sector for profitable ventures, provided they are equipped with the necessary knowledge and resources.

Introduction 
In 1804, Nicolas Theodore de Saussure demonstrated that plants don’t uptake carbon from the humus, rather it comes from the carbon dioxide in the atmosphere. He further stated that soil is source of plant nutrients. Subsequently in 1840, Carl Sprengel proposed law of minimum which mean the growth is regulated by scarcest (minimum available) resource instead of total resources. During the same time, Justus von Liebig observed that the chemical elements nitrogen (N), phosphorus (P), and potassium (K) are essential for the plant growth. He strongly popularized the theory of mineral nutrients and law of minimum by developing the barrel with multiple holes at different height and filling water in it. It has opened the door of fertilizers industries; therefore, Justus von Liebig has been described as the “father of the fertilizer industry”. Consequently, many fertilizer companies started producing various chemical fertilizers all over the world. This had increased the productivity of the various crops. In India the first fertilizer factory which produced Single Super Phosphate (SSP) was started in Ranipet, Tamil Nadu in 1906 (Chaudhary, 2023). Before, green revolution we have established fertilizers industries of Ammonium Sulphate (1933), Ammonium Sulphate Nitrate (1959), Urea (1959), Ammonium Chloride (1959), Ammonium Phosphate (1960), Calcium Ammonium Nitrate (1961), Nitro phosphate (1965) and Di Ammonium Phosphate (1967). The green revolution ushered in 1967-68 was due to introduction of input responsive high yielding dwarf variety of wheat and use of chemical (mineral) fertilizers. These chemical fertilizers alone were responsible for increasing the yield of wheat by 233 per cent (Khunt et al. 2014&2015). If chemical fertilizers would not have been used for the crop production, we would not be in the position to feed the burgeoning human population. In the pursuit of increasing productivity, we injudiciously used chemical fertilizers and overlooked the deleterious effect of it on animal, human and environmental health. Production and use of chemical fertilizers, has increased the level of Green House Gases (GHGs) in the atmosphere. To reduce GHGs and their environmental impact, alternate source of plant nutrients viz., Farm Yard Manures (FYM), composts, organic waste-derived amendments, biofertilizers, etc. started gaining popularity. Organics are also considered unsafe as during its degradation it produces CH4. Further FYM is limitedly available. Contrary, biofertilizers

Introduction
 Banana is a common man's fruit grown in about seven lakh ha area in India. Apart from fruit, banana crop generate huge quantity of waste biomass in the form of pseudostem, leaves, suckers, etc. This biomass is absolute waste in most of the states of India as of now. Further farmers are spending about Rs. 15000 to 20000/ha for disposing off this waste from their fields. The present mode of disposing off pseudostem waste in nallas, borrow pits, road side, burning etc., which are causing environmental problems. In order to utilize this waste particularly pseudostem for developing different products, a project titled; “A Value Chain on Utilization of Banana Pseudostem for Fibre and Other Value Added Products” was sanctioned under NAIP in consortium mode by ICAR, New Delhi during 2008. The project entitled, “Establishment of Secondary Agriculture unit for skill development in students and farmers” was sanctioned by PIU, under the aegis of NAHEP-CAAST sub project in 2018. Under this project “Value addition and waste management of horticultural produces” was examined in special reference to banana pseudostem as supplemental raw material for NOVEL pesticide and fungicide. In view of this, Soil and Water Management Research Unit, N.A.U., Navsari have worked in consortium comprises of Central Institute for Research on Cotton Technology (CIRCOT), ICAR, Mumbai, Manmade Textile Research Association (MANTRA), Surat and J. K. Mills Ltd., Songadh as the partners. The basic aim of this project was to develop different value added products using presently waste banana pseudostem as raw material. As envisaged in project proposal, the value added products viz; Fibre and nonwoven fabrics, handmade papers and boards, vermi-compost, enriched sap (NAUROJI Novel organic liquid nutrient) and candy have been developed which are techno economically viable. The viability is substantiated by the fact that more than ten private parties have already signed MoU with NAU, Navsari for commercial production and marketing of organic liquid nutrient prepared using banana pseudostem sap and central core candy. Simultaneously, processes for the products like microcrystalline cellulose from Fibre, sap as a mordant in textile dying, pseudostem scutcher based vermicompost as fish feed, etc. have also been standardized during the current project period. This has become possible due to highly dedicated efforts put in by the team of scientists from all the four partners and full moral boosting supports by their authorities in implementing the project smoothly.

Introduction 
Information and Communication Technology (ICT) has emerged as a transformative force in agriculture, significantly enhancing access to information, improving productivity, and promoting sustainable practices. The integration of ICT tools facilitates the dissemination of critical agricultural knowledge, enabling farmers to make informed decisions regarding planting, pest control, and market trends. This technological advancement is particularly beneficial for small-scale farmers who often face challenges in accessing timely and relevant information. ICT platforms such as mobile phones and radios play a crucial role in providing small-scale farmers with access to essential agricultural input information, aiding them in making informed decisions (Fosu & Giba-Fosu, 2024). Furthermore, ICT tools, including e-learning platforms and mobile applications, have revolutionized agricultural extension services by providing direct access to advisory services and expert knowledge. The use of social media and mobile communication has also improved interactions between farmers and agricultural experts, thereby increasing the effectiveness of extension programs (Bhat et al., 2024). The advent of digital and smart agriculture, supported by ICT, incorporates technologies such as remote sensing, precision agriculture, and automated machinery to optimize farming practices and reduce labor dependency (Yoe, 2024). Agri-informatics, a specialized branch of ICT in agriculture, leverages emerging technologies like Big Data and the Internet of Things (IoT) to develop sophisticated agricultural systems, promoting smart farming practices (Jena, 2024). While ICT provides numerous advantages, challenges such as infrastructural limitations, economic constraints, and disparities in digital literacy hinder its widespread adoption. Addressing these barriers through policy interventions and capacity-building initiatives is crucial for maximizing the potential of ICT in agriculture. Artificial Intelligence (AI) is increasingly integrated into agriculture to address contemporary challenges such as climate change, population growth, and the demand for sustainable food production. AI applications in soil and crop monitoring, predictive analytics, and agricultural robotics are gaining attraction, assisting farmers in data collection and analysis (Smith, 2020; Gupta et al., 2023). Moreover, automation in agriculture, driven by AI, addresses issues such as crop diseases, irrigation management, and pest control. Techniques like IoT, machine learning, and deep learning contribute to the automation of farming practices, increasing soil fertility and productivity (Jha et al., 2019). Robotics and automated systems minimize human intervention, thereby enhancing farm efficiency and sustainability (Eli-Chukwu, 2019). The implementation of AI in agriculture yields numerous benefits, including enhanced productivity, costeffectiveness, and sustainability. AI assists in optimizing resource utilization,

Introduction
The Directorate of Extension Education, came into existence during 1967 under Odisha University of Agriculture and Technology. This directorate is engaged with various projects viz: University Extension Block Programme, Distance Education, Digital Extension, Information wing, Gender resource center, Educational Museum besides managing 31 KVKs in 28 districts of Odisha except Cuttack and Khordha district in which University Extension Block Programme and Farmers FIRST program is in operational. This directorate adopted several innovative extension approaches which made the OUAT KVKs unique in operational modalities and effective in delivering for the development of farming community in Odisha, some of the innovative approaches are: Development of KVK Action Plan, CoE on FPOs, R-E Linkage and Krushi Samrudhi helpline.
Development Process of Action Plan
Krishi Vigyan Kendras work as a knowledge resource center in agriculture and allied field for the district (Singh et al., 2012) where in, production and supply of critical technological products, both tangible and intangible is the major component other than having scientifically maintained demonstration units, crop cafeteria etc. Development of complete feasible action plan of KVKs requires sincere efforts in identifying the real problems on one hand and sourcing the frontline technologies on the other. The logical fitment of suitable technological options for testing, in addressing situation specific problems are also an important activity requiring our understanding of the major farming systems in the AES, micro-farming situations of different crops & commodities and our scientific orientation. For this OUAT adopts a uniform action planning process since last few years which involves different activities.
1. Identifying the problems
2. Prioritizing the problems
3. Analyzing the problems and finding root cause(s) of the prioritized problems.
4. Sourcing alternative technologies and listing possible solutions nearer to hit the root cause and address the problems.
5. Taking into consideration the follow up activities require to be undertaken for previous year OFTs and FLDs
6. Planning interventions including those for other extension activities, production of critical inputs etc.
7. Consolidation of interventions and finalization of action plan with respect to OFT, FLD, Capacity building, other extension activities or combination of these.

Introduction
The modernization of farming systems across the country is transforming agriculture. Yet, public extension services often struggle to keep pace with the growing demands for knowledge dissemination due to widen gap between farmers and extension agent i.e., 5000:1 (Ragasa et al.,2013). Also, only 6.8% farmers receive extension services directly from state extension agency (GFRAS, 2012). The complexity of modern farming systems, encompassing decisions about land use, crop selection, and market access, underscores the importance of tailored specific knowledge. Strong public extension services typically reach only about 10% of farmers, a figure further constrained by limited operational resources (Bell, 2015). This gap is exacerbated by limited resources and infrastructure. In this context, Information and Communication Technology (ICT) emerges as a game-changer, offering innovative solutions to address these challenges and empower farmers with crucial insights. The integration of ICT in agriculture is revolutionizing the way knowledge and services reach farmers, especially in resource-constrained and remote regions. ICTs, such as mobile technology, have demonstrated significant potential in extending the reach of agricultural extension services. For instance, mobile hotlines now enable farmers to obtain technical advice and market information, including price updates and market locations (Aker and Mbiti, 2010). Such tools empower users, particularly in remote areas, to access vital information and communicate efficiently (Aker, 2011). To meet farmers’ diverse and specialized information needs, ICT-based models must bridge these gaps effectively. However, the success of ICT interventions depends heavily on affordability and the customization of information to address the highly localized nature of agriculture (McNamara et al., 2011; Bell, 2015).
Digital Choupal
Recognizing these challenges, Bihar Agricultural University (BAU), Sabour, has pioneered an innovative solution by introducing Digital Choupal through videoconferencing facilities at Krishi Vigyan Kendra (KVKs) and colleges of the university across the state. This initiative has supported agricultural extension by significantly reducing the barriers posed by distance and resource limitations. Bihar, a densely populated state in India with 1,102 people per sq. km, faces significant challenges in its agricultural sector. Employing around 75% of the workforce and contributing 35% to the GDP, agriculture remains a vital part of the state’s economy. However, technology adoption is slow, particularly in rural areas, due to poor connectivity and limited communication infrastructure. Less than half of Bihar’s villages are connected by roads, and access to trained extension personnel is scarce. These limitations hinder the dissemination of agricultural innovations and the provision of real-time advisory to farmers, which are essential for enhancing productivity and improving livelihoods. This innovative approach has redefined agricultural outreach, ensuring that even the most remote farmers can connect with experts and benefit from customized training and guidance.

Introduction
Technology transfer and capacity building are critical to the advancement of agriculture, particularly in ensuring that research findings and innovations reach stakeholders efficiently. The Directorate of Extension (DoE) at Kerala Agricultural University (KAU) is a key player in this process, liaising with state development departments to drive technology dissemination in the agriculture and allied sectors. The DoE collaborates closely with development departments of agri and allied areas in the State, acting as a vital link to ensure that agricultural advancements reach the grassroots level. The Directorate also integrates institutional mechanisms to support this technology transfer. Through a network of Krishi Vigyan Kendras (KVKs) and several institutional mechanisms, the Directorate integrates new agricultural technologies into mainstream practices, focusing on both skill development and sustainable development strategies. It conducts workshops, seminars, and training programs focused on enhancing the skills of extension workers, farmers, and other stakeholders. The focus is not just on disseminating new technologies but also on building long-term capacity through skill development. This ensures that the stakeholders are well-equipped to implement the innovations in a way that promotes efficiency, productivity, and sustainability. In essence, the DoE at KAU is a driving force in modernizing agriculture in Kerala. Through its structured efforts in technology transfer, skill enhancement, and the promotion of sustainable practices, it enables the agricultural sector to keep pace with scientific advancements while ensuring that the benefits are accessible and applicable at the field level.
Initiatives / Interventions of DoE, KAU
The Directorate of Extension is crucial in bridging the gap between agricultural research and field-level application through various innovative initiatives. Key interventions include the popularization of agricultural technologies, primarily through farm-based production programs, Block Level Agricultural Knowledge Centres (BLAKC), and the Mukhamukham (face-to-face) Agro Clinic. The Directorate also focuses on capacity-building programs, entrepreneurship development, and ICT-enabled technology dissemination. Additionally, the Directorate supports vulnerable sections of society, develops Farmer Producer Organizations (FPOs), and implements state-funded development projects, contributing to the holistic growth of Kerala’s agricultural sector.

If the earth’s surface is perfectly smooth, the wind flows parallel to the earth’s surface without any friction and the wind velocity will be uniform at different heights above the earth’s surface. As the earth’s surface is not smooth, it offers friction, slows down the movement of the wind near the surface. Therefore, the wind velocity increases very slowly with increase in height up to a certain level, and there after the wind velocity increases with increase in height more rapidly (Fig.5.1). When the wind speeds are measured at different heights above the ground and plotted on a graph with height Z in logarithmic scale on y-axis and wind velocity on x-axis, the wind velocity will be zero at certain height above the ground and thereafter the wind velocity uniformly increases with increase in height. The height at which the mean wind velocity is zero due to roughness is called roughness parameter (d). Therefore, the roughness parameter is defined as the height at which mean wind velocity is zero due to roughness of the earth’s surface. In a cropped soil, the crop also obstructs free movement of air. If wind profile measurements are taken in a cropped soil and are plotted on a graph with height on y-axis in logarithmic scale and mean wind velocity on the x-axis, the mean wind velocity will be zero at a height above the roughness parameter. The difference in height (Z-d) at which the wind velocity is zero when the height is plotted on logarithmic scale is called zero plane displacement (Z0). Therefore, the zero plane displacement can be defined as the height by which the roughness parameter increases due to presence of the crop (Fig.5.2).

In cropped soils, evaporation refers to evaporation of water from the soil and transpiration refers to evaporation of water from plant canopies (Fig.6.1). Evaporation and transpiration play very significant role in mass and energy transfer. The latent heat of vaporization is defined as amount of heat required to evaporate 1 gm of water at a temperature of 100°C; i.e. the boiling point of water is 540 cal/gm. The amount of heat required for evaporation of water at ordinary temperature of about say 30°C is 610 cal/gm.
Fig. 6.1: Process of evapotranspiration
The evapotranspiration from crop depends upon several factors as indicated below:
• The evapotranspiration increases with increase in air temperature.
• The evapotranspiration increases with increase in wind speed up to a certain limit.
• The evapotranspiration decreases with increase in relative humidity
• The evapotranspiration increases with increase in Saturation Vapor Pressure Deficit (SVPD). SVPD = es – ea

Agriculture is number one priority in economic planning and for the welfare of the people. It is most indispensable sector. Severe food shortages due to short comings and mismanagement of agriculture will have long lasting effect. In recent years, the uncertainties in agriculture are increasing due to climate change and farmers are required to be very vigilant and cautions right from planning of field operations till they recover their investment and end up with better returns. The governments all over the world are very much cautious of the problems of the farmers. There is greater realization that strengthening meteorological services to generate accurate and timely weather forecasts is the starting point to help farmers in carrying out appropriate management practices to ensure better crop production and minimise the risks associated with unfavourable weather situations. The farmers can manage to take their own decisions with regard to choice of crops, land preparation, fertilizer applications, weed control, irrigation scheduling etc which are of routine nature (Fig.19.1). But there are several issues for which farmers do not have adequate knowledge just based on weather forecast. It is now very much realised all over the world that there is need to transform the weather forecasts into an actionable operational agrometeorological advisories based on sound scientific hypothesis and authentic database. Though it appears to be very simple and easy solution, the agencies that

Remote sensing is a technology that enables us to acquire information about one object or phenomenon without making physical contact with the object. Generally, we are used to take observations in site or at the site. Development of remote sensing technology is now making it possible to quickly and almost simultaneously to collect information from the earth surface and other planets as well. Remote sensing is used to measure the thermal complexity and structural complexity of microclimates and how organisms respond to environmental changes. The thermal complexity is a result of the response and behaviour of different characteristics of the earth surface including vegetation, soils, structures, water bodies etc. Optical remote sensing makes use of visible, near infrared and short-wave infrared sensors to form images of the earth’s surface by detecting the solar radiation refl ected from targets on the ground. Different materials refl ect and absorb differently at different wavelengths. Thus, the targets can be differentiated by their spectral refl ectance signatures in the remotely sensed images (Fig.18.1). Satellite Refelcted Solar Radiation Forest Water Grass Bare Soil Paved Road Built-up Area Atmosphere Incident Solar Radiation Sun
Structural complexity is defi ned as minimum number of numerical specifi cations required to describe an object in physical space. Structural complexity is a key ecological factor that describes the three-dimensional physical structure of the ecosystem. It is often linked with biodiversity.

Urban climatology deals with changes in climatic conditions that prevail in large cities and towns that differ from the surroundings. Urban climates are influenced by large built-up areas, increased human activities and dense population and are found to experience differences in temperature, humidity, wind speed and direction and rainfall compared to adjoining areas. Tall buildings, paved streets and parking lots affect radiation balance, wind flow and run-off. The atmosphere in urban areas will have higher concentration of pollutants like carbon monoxide, oxides of sulphur and nitrogen, hydrocarbons, oxidants and particulate matters. Heavy concentration of air pollutants will have considerable impact on temperature, humidity, wind, and precipitation in and around urban areas. Heavy concentrations of air pollutants for longer periods or several days may lead to temperature inversions. The temperature inversions prevent convection and vertical movement of air. The centre of urban area will be warmer by even 5 to 6°C compared to adjoining areas. During summer months, the concrete structures absorb, store and reradiate more solar energy per unit area compared to vegetation. During nights, radiative losses from urban buildings and roads keep city warmer than the rural areas. The average relative humidity in cities is usually lower due to lack of evapotranspiration from vegetation. The mean wind speed will be 20 to 30 percent due to increased frictional drag induced by built up urban terrain (Fig.17.1).
The urban areas influence precipitation patterns in its vicinity as turbulence and convection get modified by city environment.
17.1. Urban Heat Islands
An urban heat island is a type of microclimate that is created when an urban area becomes warmer than the surrounding area. It is common in large cities (Fig.17.2). The characteristic features of urban heat islands are as follows:
• Increased temperature
• Large temperature difference by even 5 to 6°C
• The south facing buildings receive more sunlight in the northern hemisphere
• The tall buildings in urban areas create streets that act like deep valley
• The albedo will be very less. The darker areas lead to more absorption of incoming solar radiation and emit more of long wave radiation
• The concrete structures are built with materials having low specific heat. Therefore, concrete structures warm up faster and lead to quick rise in temperature
• The higher density of buildings reduces wind speeds.

16.1. Global Warming
The industrial revolution from mid 18th century is recognized as the primary cause of atmospheric pollution. Some of the gases like CO2, Chlorofluorocarbons, methane, nitrous oxide etc. are getting released into the atmosphere in greater volumes by combustion of fossil fuels. These gases can absorb the heat radiation leading to increase in air temperature and are called as greenhouse gases. When there is no vertical movement of air, these gases can accumulate near the ground and causes serious health hazards (Fig.16.2). Fig. 16.2: Global warming Under unstable conditions, there will be more convection and vertical movement of air that can prevent pollution near ground level. These air pollutants can be transmitted and carried away to long distance by strong winds. So, the air pollution which defies local, regional or even continental boundaries can cause atmospheric pollution and global warming. Therefore, air pollution control is not an issue for just one location or region and is now a matter of global concern.
16.2. Climate Change
As the greenhouse gases are spreading into the atmosphere, there is gradual increase in the air temperature and if no control measures are uniformly adopted

During most of the years, there will be loss of agricultural production by at least 15 to 20 per cent per annum due to unfavourable weather situations. The farmers practicing agriculture expect uniform returns every year as the investment costs are much higher and cannot afford loss in production. Of late, the inter-seasonal and intra seasonal variations in weather are very frequent. The weather conditions observed were found to exceed even beyond known limits. Exceptional deviation from any one single weather parameter like air temperature, rainfall and wind can trigger considerable loss in production or sometimes even crop failure (Fig.12.1). Fig. 12.1: Components of a microclimate and its interlinkages Large scale weather modification is not practicable to a greater extent as uniform results cannot be expected under these conditions. There is need to explore cost effective management options that may significantly alter some weather parameter that is detrimental to crop production at field level by the farmers themselves. Therefore, microclimatic modification is an emerging technology to alter or change the unfavourable weather conditions detrimental to crop growth using cost effective and easily manageable techniques for minimizing the loss in crop production. The options for microclimatic modification have to be decided based on whether and the nature of weather aberrations. For example, dry spells are most common during rainy season in most of the arid and semi-arid regions. The farmers growing crops under rainfed conditions suffer considerable loss in production due to occurrence of dry spells as the crop experiences moisture stress. These dry spells may occur any time during the growing season. In such situations, the farmer needs to adopt a management option even before sowing a crop. Sometimes, the occurrence of weather aberration cannot be anticipated and the farmer has to prepare for adopting a management option based on weather forecast. Such measures are temporary and needs to be adopted to ward off the unfavourable weather conditions to a certain extent. Microclimatic modification can be a permanent, seasonal or temporary option depending upon the climate of the region. The crop microclimate refers to the climate just above and within the crop canopy and in the soil root zone that can be influenced by the day-today management practices. Microclimate modification is a measure to change or regulate the weather parameter at farm level. The microclimate management option also depends upon the nature and type of the soil as well.

There is growing demand for increasing fruit production as fruits are considered to be healthy, nutritious and easy to digest. Fruits are natural foods and have export potential as well as provide opportunities for increasing employment by establishing fruit processing industries. Some of the fruits can be grown around the year where as some fruits are of seasonal in nature. Usually, the fruit cultivation is undertaken by establishing orchards. In case of orchards, wrong decisions in planting may result in huge loss and therefore right method of planting is the key factor for establishing orchards.
The fruit crops are of three types depending on the adoptability to the climate of the region and are grouped as
• tropical fruits
• sub-tropical fruits
• temperate fruits
The microclimate of the orchards depends upon
• height of the plants/trees
• horizontal spread
• canopy architecture
• spacing/plant density
• age of plantation
• seasonal weather
15.1. Tropical Fruits
The tropical fruits require higher temperature throughout the year. The crops do not require low temperature for breaking dormancy and for flowering. The plants are ever green and grow throughout the year. There plants are well adopted to regions where the minimum temperatures are more than 10°C and very sensitive to frost. There are grown in tropical regions between 23°N to 23°S latitudes. The optimum maximum temperature for growth and development ranges from 30 to 37°C.
15.2. Sub-Tropical Fruits
The sub-tropical fruits perform better between temperate and tropical climates as the plant requires both high and low temperatures. Some of the fruit crops are green and some of those are deciduous. The temperate fruit crops are very sensitive to frost. The sub-tropical fruit plants break dormancy of flower buds

14.1. Slope
It is a crucial topographic factor that affects water drainage, erosion and accessibility of agricultural machinery. Steep slopes increase the risk of soil erosion, and water run-off requiring erosion control measures such as contour ploughing or terracing. Slope also affects the availability of sunlight, as steeper slopes may cast shadows and influence microclimates within a field.
14.2. Altitude / Elevation
Elevation is the vertical distance of a point or location above a reference point, often mean sea level. It influences temperature, atmospheric pressure, and the types of crops that can be grown in an area. Higher altitudes generally experience cooler temperatures, which may limit the choice of crops that can thrive. Elevation affects the length of the growing season and influences the choice of appropriate crop varieties. In summary, elevation is an absolute measure of the vertical distance above a reference point (such as MSL), while it is a relative measure that describes the variation in elevation within a specific area or region. Elevation provides information about the height of a point, whereas it provides insights into the topographic features and slopes of a given agricultural landscape. Both elevation and relief are important considerations in agriculture as they influence factors such as water drainage, temperature gradients, and suitability for specific crops.
14.3. Aspect
Aspect refers to orientation of the slope (north, south, east or west). It affects the distribution of sun light; wind patterns and temperature gradients in a field. In the northern hemisphere, the north side of slope is often shaded while the southern side receives more solar radiation and heat, creating warmer microclimates and potentially influencing the choice of crops or planting strategies. Aspect can also impact the risk of frost or cold air drainage in certain regions. Whereas, in the southern hemisphere, the south side slopes get shaded and north facing slopes receive more solar radiation.
14.4. Relief
Relief refers to the variation in altitude between different points. It is a relative measure on changes in altitude across a particular landscape or agricultural area. The valley slopes are preferred sites for agriculture in mountain regions due to several reasons:
• The valley slopes offer relatively flatter terrain, making it easier for farming activities such as cultivation, irrigation and mechanization.
• The valleys tend to have better access to water resources such as rivers or streams which can be used for irrigation water.
• The valley slopes provide good sun exposure and protection from strong winds creating favourable microclimates for crop growth
• The natural drainage patterns of valleys help preventing water logging and ensure better water management.