eChapters

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

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

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

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

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

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.

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

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.

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

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

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

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

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

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.

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.

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.

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.

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:

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.

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.