eChapters

Introduction

Globally, the SOC pool of 1,550 Pg (1 Pg = 1015 g) to 1-m depth is about three times that of biotic and twice that of atmospheric pools (Post et al. 1982, Watson et al. 2000). In arid and semi-arid ecosystems, SOC contents show high degree of spatial variability due to patchiness of vegetation (Wiesmeier et al. 2009). The arid ecosystem might play a key role in mitigation of climate change effects through sequestering carbon in soils (United Nations 2011). Therefore, a suitable land use system having high C sequestration potential for arid ecosystem needs to be identified and promoted. However, the prevailing conditions of arid ecosystems normally does not support dense vegetation. Therefore, low carbon stock is expected in both above-ground vegetation and below-ground soil. Fruit trees are an integral part of arid farming system and played a significant role to improve the nutritional security and employment opportunity of farmers but also have potential role to increase carbon storage both in biomass and soil. To quickly assess the soil carbon restoration programmes, it is important to know how much soil carbon is stored in an agricultural farm through adoption of different land management practices. Therefore, reliable estimates of SOC pools are essential to establish the soil carbon sequestration programmes at different landscape scales.

Introduction

A complex spatial soil properties pattern is directly controlled by soil internal factors and anthropogenic impacts.Hartemink et al. (2001) elaborate a strong decline in mineralogy, morphology and genesis of soil research than strong increase in pedometrics applications during 1967 to 2001. Hartemink and McBratney (2008) identified this change as “soil science renaissance”. Basically, the soil science deeply rooted in agriculture, geology, and chemistry but the paradigm has been shifted from classification and inventorization to quantification of soil patterns in spatial as well as temporal patterns and their impact on the ecosystem health and hydrological cycle. The environmental keen approach explains that soil is in the center of the ecosystem and highly interacting with the biotic and abiotic factors of the ecosystem and a complex pattern and process has been co-evolved with the time.

Elevation or height data of land surface above a defined vertical datum is stored in the form of raster grids which is known as Digital Elevation Model (DEM). The DEM data can be processed to derive many useful parameters like slope, aspect, curvature, roughness, etc. This process of quantitatively describing terrain obtained from DEM data through computation of many variables is known as Digital Terrain Analysis. Digital terrain analysis has applications in the various fields like hydrology, ecology, geomorphology, etc. DEM data for digital terrain analysis are available from the satellites like ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer), Cartosat, ALOS (Advanced Land Observation Satellite), and SRTM (Shuttle Radar Topography Mission).

In this exercise, we are going to discuss the derivation of some primary and secondary terrain attributes from DEM data in R software. For performing digital terrain analysis in R, following packages are required.

6.1 Introduction

Farm ponds used in farmers’ fields are generally square shaped or rectangular shaped pyramidal structures. It has a regular side slope, depth, and top and bottom dimensions. It may be excavated/dugout pond or embankment pond. In excavated pond, the pond is constructed below the ground level. Water is collected in the pond by gravity from the adjacent catchment. In embankment type, the pond is partly above the ground and partly below. This type of pond has higher storage capacity than the dugout type pond. This type of pond has a berm and dyke/embankment around the pond. The embankment has some side slope. The pond has bottom dimensions, dimensions at the ground level as well as some dimensions at the top above the embankment. In this chapter, various dimensions of pond like depth, side slope of the pond, as well as the various dimensions at bottom, ground and top level will be discussed.

Background and Technology Intervention

The primary resource affected by the climate change is water. In arid and semi-arid regions of India, any shortfall in water supply due to climate change will enhance competition for water use for a wide range of economic, social and environmental applications. The population growth with the improved living conditions also increases the demand for food production and thereby increasing the demand of water in multiple folds in the river basins (UNESCO-WWAP, 2009). The major portion of water available in the Indian River basins are used for cultivating rice and thus poses major challenges to water management, especially during unfavourable climatic conditions.

4.1 Introduction

Discharge is also called as rate of flow. Discharge is defined as the volume of water flowing through a cross section in a unit time. It can be expressed as cubic metre per second (cumec), cubic feet per second (cusec), litre per sec (lps) etc. One cumec is equivalent to 35.5 cusecs or 1000 lps. The measurement of discharge is very important in everyday life starting from deciding the amount of irrigation to be supplied to a crop at a particular growth stage, or amount of water supply for domestic and industrial uses, for flood control and power generation etc. It plays a vital role in water resources planning. If a stage-discharge (also called as gauge-discharge) relationship for a particular gauging site is developed, then daily measurement of discharge in the gauging site is not required. Discharge can be estimated from the developed relationship of discharge versus stage if the measurement of stage is known.

3.1 Introduction

Irrigation water that is supplied to crop fields is defined by a term commonly called as discharge which is also called as rate of flow. Discharge is defined as the volume of water flowing through a cross section in a unit time. It can be expressed as cubic metre per second (cumec), cubic feet per second (cusec), litre per sec (lps) etc. one cumec is equivalent to 35.5 cusecs or 1000 lps. The measurement of discharge is very important in everyday life starting from deciding the amount of irrigation to be supplied to a crop at a particular growth stage, or amount of water supply for domestic and industrial uses, for flood control and power generation etc. It plays a vital role in water resources planning.

3.2 Methods of Discharge Measurement

The various methods of discharge measurement can be broadly classified into the following types: (i) volume method of discharge measurement (ii) flow measuring structures such as orifices, mouthpieces, flumes and weirs.

Introduction

In agriculture, plant diseases have always been a major problem, as they cause crop quality to decrease, resulting in yield. Plant disease has a range of effects from minor symptoms to serious damages in whole crop areas, which lead to high financial costs and significantly impact the agricultural economy, particularly in developing countries dependent on a single crop or on a few crops.

Various approaches have been developed to detect disease in order to avoid significant losses. Causal agents have been precisely defined by methods developed in molecular biology and immunology. However, for many farmers these techniques are inaccessible and require detailed knowledge of the field or substantial time and energy to be used. According to the United Nations Food and Agriculture Organization, most farms in the world are small and family-owned in developed countries. Such families provide food for a significant proportion of the population of the planet. However, hunger and food insecurity are not rare and there is restricted access to markets and services. For the above reasons, a great deal of work has been undertaken in order to establish methods that are sufficiently reliable and available to most farmers. Where Plant disease is an essential factor contributing to a major decline in plant production quality and quantity. Plant disease identification and classification are a significant role in improving plant production and economic development.

Dissolved oxygen (DO) refers to oxygen gas that is dissolved in water. Fish are able to absorb oxygen directly from the water into their bloodstream using gills. There are three main sources of oxygen in the aquatic environment: 1) direct diffusion from the atmosphere; 2) wind and wave action; and 3) photosynthesis. Oxygen depletion refers to low levels of DO and may result in fish mortality. A concentration of 5 mg/L DO is recommended for optimum fish health. Sensitivity to low levels of dissolved oxygen is species specific, however, most species of fish are distressed when DO falls to 2-4 mg/L. Mortality usually occurs at concentrations less than 2 mg/L. If fishes gulfing on the water surface and also show the low swimming in the water it indicates deficiency of dissolved oxygen in pond.

Soil is a bioorganic - mineral complex of the loose surface layer of the earth’s crust. Soil microbiology is the science that deals with the millions of microscopic forms of life found in the soil. It is stated that one hectare - foot (one hectare to a depth of 30cm) contains 2 to 10 metric tons of living microorganisms. Soil microorganisms are in a constant struggle for existence and are believed to be in a state of dynamic equilibrium. Without microorganisms, the soil would be an inactive geological mass incapable of supporting plant life and without plant life, animal life would not be possible. This soil population consists mainly of bacteria, fungi, actinobacteria, algae, and protozoa. The soil ecosystem includes these microbial groups as well as the inorganic and organic constituents of a given site. The collections of cells represented in the community are considered as distinct populations. All the inhabitants of the particular locality make up the community.

Types of Microorganisms in Soil

Living organisms both plants and animals, constitute an important component of soil. The pioneering investigations of several early microbiologists showed for the first time that the soil was not an inert static material but a medium pulsating with life. The soil is now believed to be a dynamic or rather a living system, containing a dynamic population of organisms/microorganisms. Cultivated soil has relatively more population of microorganisms than the fallow land, and the soils rich in organic matter contain much more population than sandy and eroded soils. Microbes in the soil are important to us in maintaining soil fertility and productivity, cycling of nutrient elements in the biosphere, and sources of industrial products such as enzymes, antibiotics, vitamins, hormones, organic acids, etc. At the same time certain soil microbes are the causal agents of human and plant diseases.

Introduction

There is different type of distributors available in the market. Depending on the basic principle of working they may be broadly classified into three major groups as below (FAO, 1980).

i. Distributors in which head loss takes place through small diameter tubes

ii. Distributors in which head loss takes place through some orifice control

iii. Distributors in which head loss takes place through a vortex action

There are many adaptations to distributors though the working distributors fall under the above stated basic principle. Tiny perforation in the laterals or porous materials allows leaking out the water serves the purpose of distributors. The compensating type distributors have long path in it to dissipate the energy and drips almost same rate within certain range of pressure variation. Whatever may be the distributors proposed to be used, the discharge characteristics should be known. The discharge characteristics should be provided by the manufacturers and preferably certified by any authorized body; otherwise to be tested by the designer before recommendation to large-scale use.

1.1 R and R studio

R has become the world-wide language for statistics, predictive analytics, and data visualization. R is not limited to statistics; it has a wide range of tools for spatial analysis and digital image analysis and can handle any process needed for image analysis flexibly. It offers a wide range of methodologies for digital image processing, from the most basic to the most complex. As an open source project, it’s freely available for a range of platforms, including Windows, Mac OS X, and Linux. An integrated development environment (IDE) for R, R Studio, allows interactive execution of R functions with user interface. RStudio is available in two formats - RStudio Desktop and RStudio Server - both available in free and fee-based (commercial) editions.

1.1.1. Download and install R

The R software setup files can be downloaded from any of the widely distributed Comprehensive R Archive Network (CRAN). To download R, please choose your preferred CRAN mirror, a location close to you. Follow the following steps:

Agricultural land drainage is adopted for removal of excess surface and subsurface water, either from irrigation or rainfall in order to improve the profitability of land use.  Drainage also plays a role in removal of salts from the root zone. Therefore, land drainage is closely linked to irrigation in arid and semi arid regions. India has a long history of practicing irrigation and drainage in its semi arid irrigated regions. During the ancient times in the Indus Valley dams and drainage system were built for cultivation of different crops. The earlier experience of drainage was more concerned with surface drainage because from time immemorial India has been experiencing floods of varying magnitudes.

Geomorphometric analysis is the measurement of the threedimensional geometry of landforms and has traditionally been applied to watersheds, drainages, hill slopes, beaches, and other groupings of terrain features. In particular basin morphometric parameters have received a lot of attention from hydrologists and geomorphologists since watersheds (catchments) have been used for analysis of various physical ecosystem processes, including soil erosion, deposition, runoff, stream discharge, sediment yield, sedimentation of streams, irradiation by sunlight, evaporation, evapotranspiration, and nutrient distribution. The study of morphometric parameters, which include variables such as average basin slope, the basin elongation ratio, compactness ratio, basin relief and stream density. Some parameters, such as slope length or stream sinuosity, can be used to represent both basin and hill slope, or basin and stream channel properties.

The main task before geomorphologists is to use an ideal unit of the earth surface for the study of its landforms. The search for an ideal areal unit, within which the collection, processing, organization and interpretation of the data of the geometry of landform, particularly of erosional origin can be made has been the main aim of the geomorphologists right from Fennemen (1914), Horton (1932 and 1945), Strahler (1956 and 1957), Miller (1953), Chorley (1957), Schumm (1956), Shreve (1966), Singh (1981), Sarkar (1995), Schumm and Spitz (1996), Sharma and Amin (1996), Iqbaluddin et al (1997) and Raj et al (1999).

Crop Water Requirements

In designing an irrigation system, the primary objective is to know the water requirement of crops. Water requirement of crops are determined either by f ield cultivation or by estimation through commonly used empirical formulae such as Blaney Criddle, radiation, Penman or pan evaporation method.

Definitions

Crop water requirement or evapotranspiration (ETcrop ): It may be defined as the rate of evapotranspiration of a disease free crop growing in a field of not less than one hectare under adequate fertility and water supply so that full productive potential can be achieved in prevailing environment. Evapotranspiration requirement of a crop refers the ETcrop and expressed in mm/day.

Reference crop evapotranspiration (ET0 ): It is the rate of evapotranspiration from an extended surface of 8 to 15cm tall green grass of uniform height, actively growing, completely shading the ground and not short of water. ET0 may be computed by using the empirical formulae and meteorological data for the specific period.

Introduction

Drip irrigation is an efficient method of application of water at the plant bottom at a rate nearly equal to the consumptive use rate of the plant, thereby minimizing the conventional water losses like percolation, runoff and evaporation from soil. It is a process of slow application of water on, above or beneath the soil by the surface, sub-surface, bubbler, and spray or pulse system. Fertilizer can also be applied with the drip water. Emitters or applicators are placed closed to the plants and used to spray water in the form of drops, tiny streams or miniature spray. In the drip system water applied from the point source advances in all direction in the soil outward from the source. Drip irrigation is essentially a low rate, low pressure, frequent and long duration application of water in plants root zone area.

Drip irrigation is also called as localized irrigation, trickle irrigation, daily f low irrigation, diurnal irrigation, drop irrigation, sip irrigation, and micro irrigation. A particular name is being popularized in any area depending on the choice of the people of that area. The International Commission for Irrigation and Drainage (ICID) has recommended the term micro-irrigation while the American Society of Agricultural Engineers (ASAE) has preferred drip irrigation. In India it is told as drip irrigation.

2.1 Introduction

Water is the most precious gift of the nature and it is also the most crucial element for sustainability of the life in the earth. India is the largest user of freshwater in the world. India’s total water consumption alone is the higher than any other continents. The Agricultural sector is the largest consumer of water followed by the domestic sector and the industrial sector. The role of irrigation water as one of the most essential inputs for crop cultivation can’t be denied. As a traditional productive input, it ensures production by acting as an agent of insurance against inadequate and inconsistent monsoon. Ultimately the outcome provides agricultural production stability. Thus, irrigation is of prime importance in cultivation of vegetable crops as it ensures favourable water balance within the root zone in addition to natural precipitation. It fulfils the crop- water demand and improves the crop production and effectiveness of other agricultural inputs. It is also an important limiting factor of crop yield, because of its association with several factors of plant environment, which directly influence the crop growth and development (Yaghi et al., 2013). The various irrigation methods under different system of irrigation differ with regard to extent of control, timeliness and adequacy of supply of irrigation water for crop cultivation. Consequently, the economic benefits and the costs due to these irrigation methods vary among different irrigation systems. The dominant method of irrigation practiced in large parts of the country is surface irrigation (basin, border and furrow) where the entire soil surface is almost f looded without considering the actual consumptive requirements of the crops. Frequent over or under irrigation create the problems of water stress or water logging leading to reduced irrigation efficiency (less than 30%).

Aerial photography is objective of getting panoramic view of earth surface to analyze the features of earth and their interrelation at particular time period which may be changed in further events. In this concerned, the observation may play a vital role in achieving the goals of photography. Undoubtedly it is widely used in social function and so on, but still awaited for scientific or research use. Drone can measure the geometry of ground surface at lower altitude with more accuracy in the form of visual feature in natural colour. flight height of drone mainly limits the large area coverage due to lower flying and drone can work perfectly at low altitude planning with good quality feature/photography.

Agricultural drones have emerged as important tools for precision farming, crop surveillance, and field-level data acquisition. This chapter introduces drones as aerial intelligence platforms capable of collecting high-resolution spatial and spectral information about crops, soil, and environmental conditions. It discusses drone architecture, sensing technologies, remote sensing, crop monitoring workflows, and crop health assessment. Artificial intelligence and machine learning enable efficient analysis of aerial imagery for disease detection, irrigation management, precision spraying, crop stress assessment, and yield prediction. The chapter also examines autonomous drones, drone swarms, IoT integration, edge computing, and digital twins. Operational limitations, regulatory considerations, data management, and sustainability implications are also addressed.