eChapters

Organic farming is increasingly recognized as a sustainable agricultural practice that prioritizes soil health, ecological balance, and long-term productivity. This article explores the intricate relationship between organic farming and soil health, detailing the principles, practices, benefits, challenges, and future prospects. Key organic farming practices such as crop rotation, cover cropping, composting, green manuring, and reduced tillage play crucial roles in enhancing soil structure, fertility, and biodiversity. While organic farming offers numerous benefits, including improved soil fertility, structure, microbial activity, and water management, it also faces challenges like nutrient management, pest control, soil erosion, and weed management. Through case studies and future perspectives, this article underscores the potential of organic farming to contribute to sustainable agriculture and environmental protection, advocating for continued research, policy support, and education to maximize its benefits.

The soil-plant-water relationship is a critical aspect of agricultural science, encompassing the interactions between soil properties, plant health, and water dynamics. This article examines the intricate connections that influence plant growth and crop productivity, highlighting the roles of soil texture, structure, and organic matter in water retention and availability. It explores how plants uptake water through root systems and how transpiration affects water distribution within the soil. The study also addresses the impact of irrigation practices and soil management techniques on optimizing water use efficiency in agricultural systems. Understanding these relationships is essential for developing sustainable farming practices that enhance crop yield while conserving water resources.

The interaction between soil and plants is a complex and dynamic process that plays a vital role in determining plant growth, productivity, and nutrient uptake. This abstract explores the intricate relationship between soil properties, root morphology, and nutrient availability, highlighting key mechanisms involved in nutrient uptake by plants. Soil serves as the primary reservoir of nutrients essential for plant growth, providing essential elements such as nitrogen, phosphorus, potassium, and micronutrients. Plant roots play a critical role in accessing these nutrients, with their morphology and distribution influenced by soil texture, structure, and nutrient availability. Various mechanisms, including root exudation, mycorrhiza associations, and ion exchange, facilitate nutrient uptake by plants, enhancing their resilience to environmental stresses and optimizing nutrient use efficiency. Understanding the dynamics of soil-plant interaction and nutrient uptake is essential for sustainable agriculture, guiding the development of management practices that promote soil fertility, crop nutrition, and ecosystem resilience.

Soil amendments and organic matter play critical roles in enhancing soil fertility, improving crop productivity, and promoting sustainable agriculture. This abstract provides an overview of the importance of soil amendments and organic matter in soil management practices, highlighting their impacts on soil structure, nutrient availability, and microbial activity. By incorporating organic amendments such as compost, manure, and green manures into soil, farmers can replenish essential nutrients, improve soil structure, and enhance water retention capacity. Additionally, soil amendments can mitigate soil degradation, erosion, and nutrient runoff, contributing to long term soil health and ecosystem resilience. Understanding the benefits of soil amendments and organic matter is essential for promoting sustainable soil management practices and ensuring food security in a changing climate.

Introduction

Rick (1984) used the term pre-breeding or developmental breeding to describe the same activity. Thus "genetic enhancement" or "pre-breeding" refers to the transfer or introgression of genes or gene combinations from unadapted sources into breeding materials (FAO, 1996)

However, enhancement has been more popularly adopted by PGR scientists. It is an emerging concept emphasizing the use of plant genetic resources

• To meet the market requirement, plant breeders have to develop improved cultivars.

• Crop improvement has led to narrowing down of genetic base resulting in slower progress (genetic gain) in plant breeding and increased risk of genetic vulnerability

Need for Genetic Enhancement

• In improving the level of resistance to biotic and abiotic stress.

• In improving quality characters such as fibre length, strength, fineness, maturity and uniformity.

• In developing early maturing genotypes, which can fit well in multiple cropping systems.

• In developing plant types suitable to machine picking etc.

• Use of germplasm will help in broadening the genetic base of cultivars as well as in creating vast genetic variability.

PPVFR act is an effective system for protection of plant varieties, the rights of farmers and plant breeders and to encourage the development of new varieties of plants. Stimulate investment for research and development to produce new plant varieties.Facilitate the growth of the seed industry that will ensure the availability of high quality seeds and planting material to the farmers. Registration of a plant variety gives protection only in India. Provides the exclusive right to produce, sell, market, distribute, import, or export the variety.

Milestones in Seed Sector

• 1957- First AICRP

• 1963 -NSC established

• 1966 -Seed act passed

• 1968- Operational

• 1971- Indian Minimum Seed Certification Standards adopted

• 1975- GSSC established

• 1977- AIC NSP launched

• 1980- GSSCA Established

• 2001- PPVFR Act passed

Mutation: Natural genetic variation has exhausted. Genetic variation can be induced by mutations or changes in the DNA sequences of the plants.

Additional Tools for Plant Improvement

Increase in yield with no additional lands available for cultivation depends on development of high yielding varieties suitable for marginal cultivation.

• Food security

• Nutritional security

Need for additional tools to increase efficiency of breeding methods for genetic enhancement and propagation.

• Genomics

Genomics – Definition

Genomics - Study of an organism's entire genome / full genetic complement of an organism.

Introduction

It refers to all activities designed to identify materials that cannot be used directly in breeding programmes, and further to transfer these traits to an intermediate set of materials that breeders can use further in producing new varieties for farmers. It is a bridge between Genetic Resources and Crop Improvement. That is collaboration between germplasm curator and plant breeder.

Crosses between adapted and exotic materials, where different proportions of introgression are obtained and evaluated, have been denominated as semi exotic materials. That should be readily used in regular breeding programme for cultivar development.

Objectives of pre-breeding 8-10 Years • Improved germplasm and associated genetic knowledge that enhance resistance expression and diversity.

• Reduce genetic uniformity in crops through the use of a wider pool of genetic material to increase yield, resistance to pests and diseases, and other quality traits.

• Identification of desirable traits/genes and their subsequent transfer into a suitable set of parents for further selection.

• Improved parental stocks which can be readily utilized within breeding programs and improved selection methodologies.

• Identify potentially useful genes in a well-organized and documented gene bank Designing strategies that lead to development of an improved germplasm that are ready to use in varietal development.

Introduction

The objec tive of genomic research in any species is to sequence the whole genome and to decipher functions of all the different coding and non-coding seq,uences. The technology for large-scale DNA sequencing has enabled the scientists to undertake genome sequencing project in a realistic time scale. Since the time of first ‘large’ genome sequencing in bacteriophage λ in 1983, the projects on different groups have been completed. Eg. Escherichia coli, Saccharomyces cerevisiae, Arabidopsis thaliana, Oryza sativa, Caenorhabditis elegans, Drosophila melanogaster, Mus musculus, Pan troglodytes, Homo sapiens.

There are certain species which have been chosen for genome projects as model organisms. A model organism is a non-human species that is used to understand biological phenomena with a thought of gaining insight into the working of other organisms. They are chosen on the basis of their small genome in size, diploid genetics with a few chromosomes, rapid life cycle, easily transformed, well positioned in plant phylogeny, small stature for plant growth in a small space, large number of seeds produced, convenient for discovery of gene-trait discovery at low cost and speed and well investigated. They include,

• Monocots – Oryza sativa

• Dicots – Arabidopsis thaliana

• Temperate grasses – Brachypodium

Genomics-driven approaches to Genebank management

• Pre-breeding can facilitate the characterization and utilization of PGRs.

• Allele mining involves searching useful alleles of genes from a wide germplasm collection.

• Transformation of germplasm collections into bio-digital resource centres like

• DNA Barcoding,

• DNA fingerprinting.

Pre-breeding

• Pre-breeding is the step before practical breeding.

• Aim - To introduce new desirable traits/genes into an adapted genetic background. This will broaden the genetic base in a breeding material in pace with environmental changes.”

• The main link between the germplasm conservation and its use in plant breeding

• A vital contribution of pre-breeding is increasing the total genetic diversity in crops and finding specific genes and traits.

• Main link between conservation of PGR in gene bank collections and utilisation of these resources in agriculture and horticulture.

• Essential for linking genetic diversity arising from wild relatives and other unimproved materials for utilization.

• These activities are a collaboration between germplasm curator and the plant breeder who need to work germplasm collections and how new traits from these collections can bred into new varieties.

Introduction

• Thus "genetic enhancement" or "pre-breeding" refers to the transfer or introgression of genes or gene combinations from unadapted sources into breeding materials (FAO, 1996).

• Genetic enhancement plays an important role in utilizing unadapted and unutilized germplasm collections and creating vast genetic variability for development of productive cultivars / hybrids.

• Objective of Genetic Enhancement is broadening the genetic base and increases genetic diversity

• Gene pool – Harlan and de Wet (1971).

• Primary gene pool (GP-1): Members of this gene pool are probably in the same "species" (in conventional biological usage) and can intermate freely.

• Secondary gene pool (GP-2): Members of this pool are probably normally classified as different species than the crop species under consideration (the primary gene pool).

• Tertiary gene pool (GP-3): Members of this gene pool are more distantly related to the members of the primary gene pool. The primary and tertiary gene pools can be intermated, but gene transfer between them is impossible without the use of "rather extreme or radical measures such as embryo rescue (or embryo culture, a form of plant organ culture) induced polyploidy (chromosome doubling) bridging crosses (e.g., with members of the secondary gene pool).

Previous Year Questions

1. What is seed treatment?

2. Factors affecting the seed quality of a crop during seed production?

3. Seed treatment campaign – Role & importance?

4. Agronomic and genetic principles of quality seed production?

5. Varietal seed production and hybrid seed production?

Seed Treatment

Seed treatment refers to the application of fungicide, insecticide or both to the seeds to disinfect(deep seated) and disinfest (over seed coat) them from seed borne or soil borne pathogenic organisms and storage insects. It also refers to subjecting the seed to solar energy exposure or immersion in conditional water.

Previous Year Questions

1. Different Classes of Seeds?

2. Various parameters of field & seed standards for breeder seed production?

3. Factors that affect the longevity of seeds during storage in warehouses?

4. Initial Seed Quality?

5. Seed Testing?

Different Classes of Seeds

1. Nucleus Seed: It is handful of seed maintained by concerned breeder for further multiplication. The nucleus seed will have all the characters that the breeder has placed in it and it is of highest genetic purity. The quantity of nucleus seed is in kilograms.

2. Breeder Seed (BS): Breeder seed is a seed or vegetative propagating material directly controlled by the originating or sponsoring plant breeder of the breeding programme or institution and or seed whose production is personally supervised by a qualified plant breeder and which provides the source for the initial and recurring increase of foundation seed. Breeder seed is exempted from certification. However, the breeder seed crop is being inspected at appropriate stages by a Monitoring Team consisting of breeder, representative of NSC and representative of Seed Certification Agency. The breeder seed lots are affixed with Golden Yellow tags. The genetic purity of breeder seed crop should be maintained at 100 per cent.

Previous Year Questions

1. What is DNA fingerprinting? Discuss the applied aspects in modern agriculture. (15M, CSE 2021)

• The term DNA fingerprinting in its original sense refers to the method developed in 1985 by Sir Alec Jeffreys (Jeffreys et al., 1985) and his associates for the simultaneous detection of highly variable DNA fragments by hybridisation of specific multilocus probes to electrophoretically separated restriction fragments?

• The DNA fingerprints, resembling barcodes, are unique to the individual and hence can be used in much the same way as conventional fingerprints - to identify individuals with absolute certainty?

DNA Fingerprinting Techniques

• A large number of fingerprinting techniques are in currency, which are variations and combinations of restriction fragmentation and polymerase chain reaction (PCR).

• Restriction fragment length polymorphism (RFLP) involves digesting DNA with restriction enzymes, separating the resultant DNA fragments by gel electrophoresis, blotting the fragments to a filter and hybridising probes to the separated fragments. Specific probe-enzyme combinations give highly reproducible patterns.

• With the advent of PCR technology a number of simpler techniques have become available for molecular characterisation.

• These include, random amplified polymorphic DNA (RAPD) and its several variants, intersimple sequence repeats (ISSR), amplified fragment length polymorphism (AFLP) and sequence tagged microsatellites sites (STMS).

Previous year questions

1. Introduction?

2. Role of private? Introduction

• The Indian seed industry used to be dominated by public sector seed companies. However, following the easing of government regulations and the implementation of a new seed policy in 1988, the private sector seed companies have started playing a major role in seed development and marketing.

• More recently, the government’s decision to embrace biotechnology as a means of achieving food security has attracted several leading biotechnology-focused multinational seed companies to India.

• The composition of the seed industry, by volume of turnover, has reportedly reached a ratio of 60:40 between the private and public sectors.

Previous Year Questions

1. Intellectual property rights (IPR) are the rights given to persons over the creations of their minds: inventions, literary and artistic works, and symbols, names and images used in commerce. They usually give the creator an exclusive right over the use of his/her creation for a certain period of time?

2. Plant varietal protection?

• The importance of intellectual property was first recognized in the Paris Convention for the Protection of Industrial Property (1883) and the Berne Convention for the Protection of Literary and Artistic Works (1886). Both treaties are administered by the World Intellectual Property Organization (WIPO).

Anatomy

The study of gross internal structure of plant organs by the technique of section cutting is called anatomy .The term anatomy was derived from two words ‘ana’ means as under and ‘temnein’ meaning to cut. Anatomy is the branch of science which deals with internal structures and organization of the organism. It is also known as internal morphology. Plant anatomy also describes tissue and tissue systems of the plant body.

1.1 Introduction to Integrated Watershed Management

Definition and Scope of Integrated Watershed Management: Integrated Watershed Management (IWM) refers to a comprehensive approach to managing the resources and ecological processes within a watershed area in a coordinated and integrated manner. Integrated watershed management represents a holistic approach to managing natural resources within a watershed, with the aim of achieving sustainable development while maintaining ecosystem health and resilience. It involves collaboration among various stakeholders and integrates scientific knowledge with traditional wisdom to address complex environmental challenges. This section aims to provide a clear understanding of what integrated watershed management entails, including its scope and key components.

a. Definition of Integrated Watershed Management: Integrated Watershed Management is a holistic and multi-disciplinary approach that considers the entire watershed as a unit for planning and managing natural resources. It involves the coordinated management of land, water, vegetation, and other resources within a watershed to achieve sustainable development goals while preserving ecological integrity.

2.1 Definition and Boundaries of Watershed Areas

Concept of Watershed Boundaries

The concept of watershed boundaries is fundamental to understanding the hydrological and ecological dynamics of a given landscape. Watershed boundaries, also known as drainage divides or catchment areas, delineate the geographical extent of a watershed, which is an area of land where all the water drains to a common outlet, such as a stream, river, lake, or ocean. Watershed boundaries represent the natural hydrological and ecological units of a landscape, reflecting the interconnectedness of water resources and ecosystems. Understanding the factors influencing their definition is essential for effective watershed management, resource planning, and environmental conservation. Exploring the delineation of watershed boundaries involves considering various factors that influence their definition:

a. Topography: Topography, particularly the elevation and slope of the land, plays a significant role in defining watershed boundaries. Watershed boundaries typically follow ridgelines or high points in the landscape, where water flows in different directions, ultimately converging into distinct drainage networks.

b. Hydrology: Hydrological characteristics, such as precipitation patterns, surface runoff, and groundwater flow, influence the delineation of watershed boundaries. Areas with higher rainfall or snowmelt may have larger watersheds with more extensive drainage areas, while areas with low precipitation may have smaller, more localized watersheds.

3.1 Land Use and Land Cover Analysis

Concept and Importance: Understanding the significance of land use and land cover analysis in watershed management for assessing spatial patterns of human activities and natural ecosystems.

Land use and land cover analysis is a fundamental tool in watershed management, providing valuable insights into the spatial patterns of human activities and natural ecosystems within watersheds. Here's an exploration of the concept and importance of land use and land cover analysis in watershed management:

a. Concept: Land use refers to the human activities and practices conducted on the land, including residential, commercial, industrial, agricultural, recreational, and conservation activities. Land cover, on the other hand, refers to the physical and biological features of the land surface, including vegetation, water bodies, bare soil, impervious surfaces, and artificial structures. Land use and land cover analysis involves mapping, classifying, and quantifying the spatial distribution and temporal changes of different land use and land cover types within watersheds using remote sensing, Geographic Information Systems (GIS), and field surveys.

b. Significance: Land use and land cover analysis is essential for watershed management due to its significance in understanding the interactions between human activities and natural processes, assessing environmental impacts, and guiding land management decisions. Key reasons for the importance of land use and land cover analysis in watershed management include:

4.1 Demographic Profile of Watershed Communities

• Population Distribution: Examining the spatial distribution and density of population within watershed areas, including rural settlements, urban centers, and peri-urban zones. Analyzing population distribution within watershed areas involves understanding how people are distributed across various types of settlements, including rural, urban, and peri urban zones. Here's a breakdown of each:

a. Rural Settlements: These are typically smaller communities dispersed throughout the watershed area, often engaged in agriculture, forestry, or other primary industries. Population density in rural areas tends to be lower compared to urban centers. The distribution of rural settlements can be influenced by factors such as terrain, availability of natural resources, and historical land use patterns.

b. Urban Centers: Urban areas within watershed boundaries consist of cities and towns with higher population densities and more developed infrastructure. These areas are characterized by a concentration of economic activities, services, and amenities. Population distribution within urban centers can vary widely, with some areas experiencing high population density in downtown cores and others having more spread-out suburbs.

5.1 Participatory Approaches to Watershed Management

Community Engagement Strategies: Exploring methods for involving local communities in decision-making processes, project planning, and implementation, including participatory rural appraisal (PRA), stakeholder consultations, and community meetings. Exploring methods for involving local communities in decision-making processes, project planning, and implementation is essential for promoting ownership, sustainability, and effectiveness of development initiatives within watershed areas. Here are key community engagement strategies:

a. Participatory Rural Appraisal (PRA): PRA is a participatory approach that involves community members in assessing their own needs, priorities, resources, and capacities. PRA techniques, such as transect walks, social mapping, seasonal calendars, and wealth ranking, enable communities to identify and analyze local issues, strengths, and opportunities. PRA fosters dialogue, builds trust, and empowers communities to take ownership of development processes.

b. Stakeholder Consultations: Conduct stakeholder consultations to engage a diverse range of actors, including community members, local leaders, government officials, civil society organizations, and other stakeholders. Consultations provide opportunities for stakeholders to share their perspectives, knowledge, and concerns, and contribute to decision-making and project design. Stakeholder consultations ensure inclusivity, transparency, and legitimacy in development processes.

c. Community Meetings: Organize community meetings, village assemblies, or public forums to facilitate dialogue, consensus-building, and decision-making among community members. Community meetings provide platforms for discussing development priorities, reviewing project progress, and resolving conflicts collaboratively. They foster social cohesion, collective action, and community mobilization around shared goals and aspirations.

6.1 Introduction to Remote Sensing in Watershed Management

Remote sensing involves acquiring information about the Earth's surface without physical contact, using satellite or aerial imagery. This technology has revolutionized watershed management by providing detailed and timely data, crucial for effective planning and decision-making.

6.2 Remote Sensing Technologies and Techniques

Satellite Imagery

Satellite imagery involves capturing images of the Earth from space using satellites equipped with sensors. Some of the most notable satellite missions providing high-resolution imagery for large-scale environmental monitoring include Landsat, Sentinel, and MODIS.

a. Landsat: Operated by NASA and the US Geological Survey, Landsat satellites have been observing the Earth since 1972. Landsat provides medium-resolution images (15-60 meters per pixel) in both visible and infrared wavelengths, allowing for detailed monitoring of land use, vegetation health, and water bodies.

Introduction

Intensive production of agricultural crops has contributed to decline in soil quality, leading to lower crop productivity and farm profitability. Major causes of this decline are soil compaction, surface crusting, low organic matter, increased pressure and damage from diseases, weeds, insects, and other pests, as well as a lower density and diversity of beneficial soil organisms. These constraints have increased the interest of farmers in assessing the health status of their soils and in implementing sustainable soil management practices. Soil health is critically important to sustainable agricultural productivity and environmental well being. Healthy soils provide a range of environmental services including water infiltration, habitat provision and profitable and sustainable agriculture.

Introduction

Over 250 million people are directly affected by land degradation worldwide. Each year 12 million hectares are lost to deserts. Only 11 % of the global land surface can be considered as prime or Class-I land.

India contains 2.4 % of world’s total land. Out of the total geographical area of 329 million ha of the country, land use statistics are available for about 93 % of the total area which comes around 306 million ha. The arable land (net area sown plus the current and other fallow lands) was estimated at 166.14 million ha (54.2%) while the area under forest was accounted at 69.02 million ha (22.6%). Land put to non-agricultural uses was estimated at 22.97 million ha (7.5%) and the barren and uncultivable land at 19.44 million ha (6.4%). Permanent pastures and other grazing lands where estimated 11.04 million ha. (3.6%), land under miscellaneous uses at 3.62 million ha. (1.2%) and the cultivable waste land at 13.08 million ha (4.5%). By summing up these figures, the reporting area comes out 306 million ha.

Introduction

Soil is a very precious natural resource. It is considered as the epicentre of all the life forms on earth. One cm of soil takes about 1000 years to form but if not used sustainably and managed properly, it may degrade and get converted into a wasteland in just few countable years. The heavy population load, rapid industrialization, unscientific agricultural practices have already put a lot of pressure on soil resulting in reduced soil fertility, degraded wastelands and problematic soils. In India, out of the 329 m ha of geographical area, nearly 50% is subjected to degradation by the various agents like water, wind and biotic interference. In this chapter we will focus on the wastelands and problematic soils, their distribution, cause of formation, management practices mainly in respect to the Indian state of Jharkhand.

Introduction

Pedology:- Pedology word drive from Greek word pedon, means soil or earth and logos means to study. Pedology is concerned with origin of the soil, its classification, distribution and character (Physical, Chemical and Biological).

Definition:- Soils are natural bodies made from both mineral and organic materials and capable of supporting plants out-of-doors.

Composition of soil on volume basis (Soil components)

i. Mineral matter :- 45%

ii. Organic matter :- 5%

iii. Soil water :- 25%

iv. Soil air :- 25%

Soil formation is a long term process. It takes several million years to form a thin layer of soil. The soil is made up of broken down rock material of varying degree of fineness and changed in varying degrees from the parent rocks by the action of different agencies such that the growth of vegetation is made possible. As soil is a complex mixture of various components, its formation is also more complex. The Formation of a particular type of soil depends upon the physico-chemical properties of the parent rock, intensity and duration of weathering, climatic and other parameters.

Introduction

Soils are formed by weathering of rocks and minerals and all soils contain some amount of soluble salts. Many of these act as a source of essential nutrients for the healthy growth of plants. However, when quantity and quality of salts in the soil near rhizosphere exceeds a particular value, growth, yield and/or quality of most crops is adversely affected. Such a soil is called salt-affected. The degree of adverse effects depends upon the type and quantity of salts, crop and its variety, stage of growth, cultural practices and environmental factors viz. temperature, relative humidity, and rainfall etc. Development of salinity and waterlogging is a serious problem in arid and semi-arid regions of the world and threatening the sustainability of irrigated agriculture.

Soil degradation resulting from salinity and sodicity is a major environmental threat to soil fertility and agricultural productivity in arid and semiarid regions of the world. Saline–sodic soils are degraded due to the simultaneous effect of salinity and sodicity. This causes loss of soil physical structure by clay swelling, and dispersion because of high Na+ concentrations in the soil solution or at the exchange phase. Apart from these physicochemical effects, this leads to biological properties, such as microbial respiration and biomass, becoming worse. On the other hand, salinity affects plant growth by creating osmotic imbalances and specific ion toxicities, which pose limitations to morphological, histological, chemical, biochemical, and metabolic processes. In turn, these reduce stomatal opening and photosynthetic rate, leading to decreased plant growth, crop yield, and quality.

Introduction

The optimum soil pH for plant production is one that is slightly acidic, at this pH soil microorganisms are most active and plant nutrients are readily available. At extremes of high (alkaline) and low (acidic) pH this delicate balance is disturbed and plant nutrients that were in adequate supply can become either deficient or toxic to plant growth. Some essential nutrients such as phosphorous, calcium, magnesium and molybdenum become unavailable if the soil pH becomes too acidic. Acidic conditions will result in a lowering of plant production in farming systems. This will result in reduced profitability and an increased reliance on fertilizers to sustain any form of productive agriculture. Correcting soil pH to a more favorable pH range will increase the availability of essential nutrients.

Introduction

Soil is one of the crucial natural resources that support life on the earth and controls the economic conditions of the nation. Soil erosion has become a serious problem in both rainfed and irrigated areas of India thus it of vital importance to raise awareness about soil erosion and their reclamation / management methods, so that future land management decisions can lead to more sustainable and resilient agricultural systems. In India almost 130 million hectares of land, i.e., 45 % of total geographical surface area, is affected by serious soil erosion through gorge and gully, shifting cultivation, cultivated wastelands, sandy areas, deserts, and water logging.

In India, the soil is eroded at an average annual rate of 16.35 tonnes per hectare which means 5334 million tonnes per year for the country as a whole. Out of this, about 29 per cent is permanently lost to the sea, while 61% is simply transferred from one place to another, and the remaining 10% is deposited in reservoirs (which mean the storage capacity is reduced by 1-2 per cent annually (Narayana and Ram Babu, 1983)). Singh et al. (1990) estimated that the average annual soil loss is about 15.2 tonnes per hectare and at national level it amounts to about 4978 million tonnes annually. The annual erosion rates vary from region to region. In dense forests covers, snow-clad cold deserts and arid regions of western Rajasthan, the annual erosion rates are less than 5 tonnes per hectare. On the other hand, about 64 per cent of the total soil is contributed by highly to very severely eroded areas, such as the Shiwalik hills (annual rate is more than 80 tonnes per hectare), the Western Ghats, black and red soil regions, ravines and other gully eroded areas and the northeastern region. For the first time, Gurmel Singh prepared map of soil erosion in India (Fig. 7.1), on the basis of iso-erosion lines i.e. line joining the place of same erosion rates.

Submerged soils/Flooded soil

Submerged soils are the type of soils that are saturated with water for a sufficiently long time in a year. This gives the soil the following distinctive gley horizons resulting from oxidation-reduction processes:

The soil is intermittently saturated with water, oxidation of organic matter is slow and it accumulated within the “A” horizon. Fe and Mn are deposited as rusty mottles or streaks if the diffusion of O2 into the soil is slow in the second horizon, whereas if the diffusion is rapid, they are deposited as concretions.

Types of submerged soils

1. Waterlogged soils- Waterlogged soils are saturated with water for a sufficiently long time annually to give the soil the distinctive gley horizons resulting from oxidation-reduction processes. Saturation with water may be due to impermeability of the soil material, or the presence of an impervious layer, or a high water table.

2. Marsh Soils- These types of soils are more or less permanently saturated or submerged. Freshwater marshes can be classified according to their origin into upland, lowland, and transitional. Upland marshes are poor in bases and have pH 3.5-4.5 because they receive mainly rainwater. Lowland marshes are saturated or submerged with water-carrying bases and have pH 5.0-6.0.

Introduction

Environment pollution is a burning topic of the day. Air, water and soil are being polluted alike. Soil being a “universal sink” bears the greatest burden of environmental pollution. It is getting polluted in a number of ways. There is importance in controlling the soil pollution in order to preserve the soil fertility and increase the productivity. Pollution may be defined as an undesirable change in the physical, chemical and biological characteristics of air, water and soil which affect human life, lives of other useful living plants and animals, industrial progress, living conditions and cultural resources. A pollutant is something which harmfully interferes with health, comfort and environment of the people. Most pollutants are introduced in the environment by waste, accidental discharge, sewage or else. They are by-products or residues from the production of something useful. Due to this our valuable natural resources like air, water and soil are getting polluted. The basis of agriculture is Soil. All crops for human food and animal feed depend upon it. We are losing this important natural resource by the accelerated erosion to some extent. In addition to this the huge quantities of man-made waste products, sludge and other product from new waste treatment plants, and even polluted water are also causing or leading to soil pollution. In order to preserve the fertility and the productivity of the soil.

Introduction

Calcareous soils are those that contain high levels of calcium carbonate (CaCO3 ) that affects soil properties related to plant growth, such as soil water relations and the availability of plant nutrients (Elgabaly, 1973), and give effervescence visibly releasing CO2 gas when treated with dilute 0.1 N hydrochloric acid. The pH of calcareous soil is > 7.0 and also regarded as an alkaline (basic) soil.

Calcareous soils have often more than 15% CaCO3 in the soil that may occur in various forms (powdery, nodules, crusts etc.). Soils with high CaCO3 belong to the Calcisols and related calcic subgroups of other soils. They are relatively widespread in the drier areas of the earth. They occupy >30% of the earth’s surface, and their CaCO3 content varies from just detectable up to 95% (Marschner, 1995).

Formation of calcareous soils

Calcareous soils occur naturally in arid and semi-arid regions because of relatively little leaching. They also occur in humid and semi-humid zones if their parent material is rich in CaCO3 , such as limestone, shells or calcareous glacial tills, and the parent material is relatively young and has undergone little weathering. Some soils that develop from calcareous parent material can be calcareous throughout their profile. This will generally occur in the arid regions where precipitation is scarce. It has been estimated that these soils comprise over one-third of the world’s land surface area (Taalab et al. 2019, Aboukila et al. 2018).

Introduction

Desert soils are the soils of arid regions that remain dry for most part of the year and support sparse xerophytes. The amount of water received by precipitation is far less than what is lost by evapotranspiration. Most deserts receive an average precipitation of less than 400 mm. Because of extreme imbalance between evapotranspiration and precipitation, many desert soils contain salts.

Distribution

Deserts occupy about one-third of the areas of Africa and Australia, 11% of Asia and about 8% of the Americas (Boul et al. 1997). Desert soils include both cold and hot desert. In India, desert soils occur in three agro-ecological regions (AER). The cold arid desert of extreme north (Leh, Ladakh region of Jammu & Kashmir ), the hot arid desert of north western India (Rajasthan, southern parts of Haryana and Punjab and northern parts of Gujarat) and the tropical arid desert of the Deccan plateau in South India represents AER 1, 2 and 3, respectively. The three different desert regions in India have characteristic climatic and soil conditions.

Introduction

Black cotton soils are formed by the solidification of molten magma; it covers a large area of the Deccan plateau. The depth of this soil is very high in the lower part of the Krishna – Godavari basin. The clay fraction is very high which is responsible for the heavy waterlogging in the area of heavy rainfall and become more vulnerable to soil erosion. The fine fraction of soil not allows draining out through the soil profile and at the same time the rate of evaporation is low. During summer soils suffer from moisture stress and it becomes very hard but at the same time during the rainy season moisture content very high. this imposes severe constraints on conventional agriculture use as a result most of the land remains fallow and subjected to soil erosion due to heavy rain. The nutrient status of the soil is quite good in Vertisol but these constraints limit crop production. To manage black cotton soil for crop production it is advisable to use animal-powered devices for surface soil drainage, Counter cultivation, adoption of a new cropping system will be helpful for better crop production.

Introduction

Irrigated agriculture is dependent on an adequate water supply of usable quality. The water quality used for irrigation is essential for the yield of crops, maintenance of soil productivity, and protection of the environment as well. The quality of irrigation water is defined with respect to its effect on plant growth, soil properties, soil biological equilibrium, and irrigation technology. Conceptually, water quality refers to the characteristics of a water supply that will influence its suitability for a specific use, i.e. how well the quality meets the needs of the user. Specific uses have different quality needs and one water supply is considered more acceptable (of better quality) if it produces better results or causes fewer problems than an alternative water supply. For example, good quality river water which can be used successfully for irrigation may be unacceptable for municipal use without treatment to remove its sediment load. Similarly, snowmelt water of excellent quality for municipal use may be too corrosive for industrial use without treatment to reduce its corrosion potential.

Introduction

One of the most common concerns in irrigated agriculture is regarding water quality or salinity. Out of the ground water surveyed in different Indian States, as much as 84% is rated either saline or alkaline (Minhas 1996). Salinity management is very important for using saline water in irrigation safely. This requires an understanding of how salts affect soil as well as plants, of how hydrogeologic processes affect salt accumulation, and also of how cropping and irrigation activities affect soil and water salinity.

The objectives of management practices for getting optimal crop production with saline irrigation water include the prevention of salt build-up in soil which limit the productivity of soils and the control of salt balances in the soil-water system, as well as minimising the damaging effects of salinity on crop growth (Meiri and Plaut 1985). Amongst the various soil, water, and crop management options available, there is usually no single way to achieve safe use of saline water in irrigation but many different approaches and practices can be combined into satisfactory irrigation systems using saline water. The appropriate combination depends upon edaphic, hydrogeologic, climatic factors as well as social and economic condition of the farmer. Several practices interact with each other, and should be considered in an integrated manner, along with climatic and human factors. Because of the climate, the basic principles of saline water management need some adaptation, e.g. providing for a leaching requirement is not appropriate when the growing season for post-monsoon winter crops starts with a surface-leached soil profile, because it would increase the salt load. High salinities during the initial stages of growth are particularly harmful. Recommendations for effective management of irrigation water salinity depend upon local soil properties, climate, and water quality; options of crops and rotations; and irrigation and farm management capabilities

Remote sensing

It is the art and science of obtaining information about an object, area, or phenomenon through the analysis of data acquired by a device without being in physical contact. Remote sensing technology involves acquiring information about the earth’s surface and atmosphere, using satellite based sensor, interpretation, of spectral measurements and characterization of land resources and environmental phenomena.

The information recorded by this technology is not visible to humankind. It provides synoptic view as well as three-dimensional view of larger area. And data are received periodically and helps in monitoring the changes at short intervals. The data recording is unbiased one which is stored permanently and can be used in many applications. Thus, processing of data is faster than the conventional interpretation method. Thus, soil resources data collected by extensive ground surveys and soil maps were prepared using cartographic techniques these were tedious, costly and time consuming. Multi date, multi spectral and real time satellite data provide a reliable accurate tool for assessment and repeat coverage of the same area at the same local time for monitoring soil resources (Joshi, 2013). In remote sensing, reflected energy from the object is recorded by a sensor. The information about the object is obtained through the analysis of reflected rays. Three energy interactions occurs when electromagnetic energy falls on any surface feature i.e., reflection, absorption and transmission.

Introduction

The term multipurpose trees (MPT) refers to all woody perennials that are grown to provide more than one significant function (shelter shade, land sustainability) of the land use system they implement. More emphasis is given to trees which are indigenous in nature and have the capability to fix atmospheric nitrogen. All trees are said to be multipurpose. The term “multipurpose” as applied to trees for agroforestry refers to their use for more than one service or production function in an agroforestry system (Burley and Wood, 1991).

Multipurpose trees species (MPT) are grown to provide more than one significant crop of function or form. These may include fuel wood, fiber, fodder, flower, fruit, fertilizer (6F) timber, industrial purpose, nitrogen f ixing, soil conservation, soil protection and rehabilitation, shade and nurse trees, medicine, windbreak, shelterbelts, live fences, aesthetic or recreational purpose, shown in Table 16.1.

Introduction

Soil pollution is anything that causes contamination of soil and degrades the soil quality. It occurs when the pollutants causing the pollution decrease the quality of the soil and convert the soil inhabitable for micro and macro organisms living in the soil. Soil pollution can occur either because of human activities and/or natural processes. However, mainly it is due to human activities. The soil contamination can occur due to the presence of chemicals such as ammonia, pesticides, lead, herbicides, mercury, nitrate, naphthalene, petroleum hydrocarbons, etc. in an excess amount.

Soils can be polluted with several organic and inorganic pollutants. Organic pollutants contain hazardous persistent organic compounds viz. polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins (PCDDs), polychlorinated biphenyls (PCBs), polychlorinated naphthalines (PCNs) and other persistent organic compounds. Inorganic pollutants contain heavy metals like lead (Pb), cadmium (Cd), mercury (Hg), zinc (Zn), copper (Cu), arsenic (As) and nickel (Ni) as well as some radioactive compounds or radionuclides. The major sources of soil pollutants are anthropogenic. It contains mainly two sources, point and diffuse; the point sources contains industrial wastes, municipal wastes, domestic wastes, medical wastes, agrochemicals, agricultural wastes, composts and sludges and nuclear wastes. Organic and inorganic soil pollutants can be toxic for plants, animals soil organisms and others. Some compound of the soil pollutants enter into the food chain and can adversely affect on human health. Soil pollutants can be also transferred to surrounding air and water through leaching, volatilization, runoff and dust storms. Quality of air and water adversely affected can be degraded. Thus, remediation of polluted soils has become an awful necessity in many areas of the world.

Introduction

Land capability classification is one of the very important issues in terms of sustainable land use. Land is the most valuable natural resource which needs to be harnessed according to its potential. Land use planning and management is a known strategy for achieving sustainable development. A properly prepared land use plan based on sound scientific and technical procedures, and land utilization strategies can summarize rationally the future demands. This accompanied by a strong planning process, where communities and various stakeholders are involved, can strengthen the decision making process on allocation and utilization of land resources. Land capability is referred as suitability of the land based on inherent characteristics of the soil associated land features, and climatic conditions that limit their safe use under agriculture, forestry etc. Land capability classification is a system of grouping soils primarily on the basis of their capability to produce common cultivated crops and pasture plants without deteriorating over a long period of time. The capability classification is one of a number of interpretive groupings of soils made primarily for agricultural purposes, mainly based on the inherent soil characteristics, external land features and climatic factors that limit the use of land for agricultural purposes. The land capability is governed by the different land attributes such as the type of soil, its depth and texture, underlying geology, topography, hydrology, etc. It also includes soil irrigation classes and ground water table position to decide overall suitability of lands for sustained use under irrigation. The classification points out automatically the possibilities and limitations of the climate and soil for each crop and type of agriculture.

Introduction

Before start of this chapter some pertinent questions need to be answered. What are different agro ecology and what are the problem soils. Since dawn of agriculture in early 2000 B.C. man has been doing agriculture as subsistence farming to cater the needs for his own consumption. Later on as the population increased, the availability of land per pearson reduced and further the commercialization of agriculture after world war II, particularly in industrialized nation, compelled farmers to increase productivity per unit area. The green revolution involving higher fertilizer uses, more use of agrochemicals together with evolvement of improved crop varieties in later part of twentieth century played vital role in producing higher grain production resulting the global production triplet in contrast to merely increase in total global cultivated area to the extent of 10%.

The catastrophe of green revolution was realized in later years when reports of soil health degradation started appearing. Intensified agriculture characterized by excessive use of fertilizers, agrochemicals and unsupportable level of over exploitation of natural resources led to serious degradation of ecosystem. Thus management of agroecosystem has reached to a crossroad with serious pressure to increase productivity simultaneously holding the soil health with prime concern for future generation. Thus the soil heath under different agroecosystem are posing problem as the soil productivity has not reached to plateau level but has started reducing year after year. Thus such soils are becoming problem which need special attention to bring them back to support higher crop production.

Arrangement of plants and animals into groups according to their close resemblance, naming and describing them is called classification. Classifying the plants into groups is called systematic botany. The main aim of classification is to name the plant to describe them and to bring out their resemblances in order to throw light on their relationship and common ancestor. It is to indicate primitive and advanced plants systematically.

Need for Classification

It is not possible for anyone to study all the organisms. But if they are grouped in some convenient way the study would become easier as the characters of a particular group or a family would apply to all the individuals of that group. Classification allows us to understand diversity better.

Classification of plants

Entire plant kingdom is divided into four main groups.

1. Thallophyta 2. Bryophyta 3. Pteridophyta 4. Spermatophyta or Phenerogams

Development of Plant Body

A vascular plant begins in existence as a morphologically simple unicellular zygote (2n). The zygote develops into the embryo which in the long run develops into the mature sporophyte. The development of the sporophyte (2n) involves division and differentiation of cells and organization of cells into the tissue systems. The embryo of the seed plant possesses relatively simple structure as compared to the mature sporophyte. The embryo bears a limited number of parts containing generally only axis bearing one or more cotyledons. The cells and the tissues of this structure are less differentiated. However, the embryo grows further, because of the presence of the meristems, at two opposite ends of the axis, of future shoot and root. After germination of the seed during development of the shoot and root new apical meristems appear which cause a vegetative growth and reproductive stage of the plant attained.

Fundamental Parts of the Plant Body

The plant body consists of a number of organ i.e., root, stem, leaf and flower. Each part has different functions for plant growth.Flower consists of sepal, petals, stamens, carpels and sometimes also sterile members. Each organ is made up of number of tissue systems; each tissue system consists of number of tissues. Tissue consists of group of cells that are alike in origin, structure and function.

Meristematic Tissues

These are composed of cells that are in state of division or retain the power of dividing. These cells are essentially alike and isodiametric. They may be spherical, oval or polygonal and their walls thin and homogeneous; the protoplasm in them abundant and active with large nuclei, and the vacuoles small or absent.

Classification of Meristems

Meristems are classified in different ways on the basis of certain factors.

A) According to their origin and development

1. Promeristem or primordial meristem

2. Primary meristem and

3. Secondary meristem.

Primary Dicot Stem

A stem with only primary permanent tissues is called primary stem. It represents a young stem. The different tissues present in dicot stem are arranged in concentric layers. e.g. Sunflower

I) Epidermis

Epidermis is the outermost layer of the stem. It is made up of compactly arranged parenchymatous cell, which look rectangular in transverse section. The cells are transparent and devoid of chloroplasts. The outer walls are convex, thickened and cutinized. On the outer side they possess a layer of cuticle. The internal walls of the epidermal cells are thin. The radial walls are thick towards the outer side and gradually become thin towards the inner side. Pits occur in the radial walls. The epidermis of sunflower bears several unbranched multicellular hair. At place the epidermis contains minute pores called stomata or stoma. Each stomata or stoma has a pair of specialized kidney shaped cells called guard cells. The guard cells have a few chloroplasts. By their swelling, the two guard cells can form a pore between them.

Primary Dicot Root

A young dicot root which does not possess secondary tissues but only the primary permanent tissues (tissues derived from the apical growing point) is called primary dicot root. It is generally cylindrical in outline and possesses the following tissues.

I) Epiblema or Piliferous Layer

It is the outermost layer of the root. It is made of compactly arranged thin walled and slightly elongated parenchymatous cells. Epiblema of a root differs from the epidermis of the stem in being devoid of distinct cuticle and stomata. Some cells of the epiblema give rise to thin – walled tubular outgrowths called root hairs. In some plants the root hair mother cells are shorter in comparison to other epiblema cells. The root hairs and piliferous layer (pilus – hair, ferre to carry). The root hair and thin walled epiblema cells absorb water and mineral salts from the soil. Root hairs commonly do not live for more than one week. With their death the epiblema cells become suberised and cutinised.

II) Cortex

It lies below the epiblema. The cortex is made up of many layers of thin walled parenchyma cells. The parenchyma cells may be rounded or angular. They enclose inter-cellular spaces for diffusion of gases.The cells of the cortex store food. They also conduct water from the epiblema to the inner tissues.

Secondary Growth in Dicot Stem

The formation of secondary tissue from the lateral meristem is called secondary growth. It increase in diameter of the stem. A stem with secondary tissues is called secondary stem. Secondary tissues are formed by two types of lateral meristem, vascular cambium and cork cambium or phellogen. Vascular cambium produces secondary vascular tissues while phellogen form periderm. Secondary growth occurs in perennial dicots such as trees and shrubs. It is also found in the woody stems of herbs. In such cases, the secondary growth is equivalent to one annual ring, e.g. sunflower.

Formation of secondary vascular tissues

They are formed by the vascular cambium. Vascular cambium is produces by two types of meristems: intrafascicular and interfascicular cambium.

1. Intrafascicular cambium is a primary meristem which occurs as strips in vascular bundles.

2. Interfascicular cambium arises secondarily from the cells of medullary rays which occur at the level of intrafascicular strips.

3. These two types of meristematic tissues get connected to form a ring of vascular cambium

The tissue system

A group of tissues performing a similar function irrespective of its position in the plant body is called a tissue system. In 1875, Sachs recognized three tissue systems in the plants.

a) Epidermal tissue system

b) Vascular tissue system

c) Fundamental tissue system.

a) Epidermal tissue system

Epidermal tissue system is the outermost covering of plants. It consists of epidermis, stomata and epidermal outgrowths. Epidermis is generally composed of single layer of parenchymatous cells compactly arranged without intercellular spaces. But it is interrupted by stomata. In leaves, some specialized cells which surround the stomata are called the guard cells. Chloroplasts are present only in the guard cells of the epidermis. Other epidermal cells usually do not have chloroplasts. The outer wall of epidermis is usually covered by cuticle. Stoma is a minute pore surrounded by two guard cells. The stomata occur mainly in the epidermis of leaves. In some plants such as sugarcane, the guard cells are bounded by some special cells. They are distinct from other epidermal cells. These cells are called subsidiary or accessory cells. Trichomes and root hairs are some epidermal outgrowths. The unicellular or multicellular appendages that originate from the epidermal cells are called trichomes. Trichomes may be branched or unbranched. Rhizodermis has two types of epidermal cells - long cells and short cells. The short cells are called trichoblasts. Root hairs are produced from these trichoblasts.

The macroscopic characteristics of wood give the clues to the conditions under which the wood is grown, provide an indication of physical properties and serve as an aid in wood identification.

Growth rings do not always appear as distinct alternating bands of earlywood and latewood. Some hardwoods, for example, form large-diameter pores early in a growing season and much smaller pores later in the year; such woods are called ring-porous. Discontinuous rings are occasionally found in trees having one-sided crowns and in heavily defoliated, suppressed, and over mature trees. Examination of a stem cross-section often reveals a dark-colored center portion surrounded by a lighter-colored outer zone. The dark center area is known as heartwood and the lighter tissue as sapwood. Trees in which fibers are spirally arranged about the stem axis are said to have spiral grain.

Wood can often be identified by macroscopic characteristics, particularly by colour, gloss, odour, weight and structure. Wood have two types of features:

A) Macroscopic or Gross feature

B) Minute structure feature