eChapters

Crop improvement is essential for developing horticultural varieties with superior yield, quality, resistance, and adaptation. This chapter introduces conventional breeding methods such as selection, hybridization, backcrossing, and mutation breeding, along with modern approaches involving molecular markers and biotechnology. Important breeding objectives include disease and pest resistance, abiotic stress tolerance, improved nutritional quality, shelf life, fruit characteristics, and market preference. Modern techniques such as marker-assisted selection, genomic approaches, and genome editing can accelerate the development of improved cultivars. The chapter connects traditional genetic principles with contemporary breeding technologies and explains how integrated breeding strategies can address changing production environments, consumer requirements, and emerging horticultural challenges.

Horticultural crops comprise a diverse group of plants differing in botanical characteristics, growth habits, climatic requirements, economic uses, and production systems. This chapter presents systematic approaches for classifying horticultural crops into fruits, vegetables, flowers, plantation crops, spices, medicinal and aromatic plants, and other specialized groups. Classification based on botanical relationships, life cycle, climate, growth habit, edible parts, and commercial utilization is discussed to provide a practical understanding of crop diversity. Knowledge of classification helps students identify crops, understand their biological relationships, select appropriate production practices, and organize horticultural resources. The chapter establishes an essential foundation for crop-specific management and improvement

Introduction

Rice straw is produced as a by-product of rice production at harvest. Agricultural Waste Burning (AWB) is a major contributor of air pollution in many countries, particularly in South Asia. Exposure to fine particulate matter less than 2.5 μm (micrometer), also known as PM 2.5, released by AWB can cause premature mortality due to respiratory and cardiovascular diseases (Brauer et al.,2012). Combine Harvesters used on the spring rice crop leave behind stubble and straw on the field (Sidhu et al., 2007). Farmers burn the rice residue while preparing the field for wheat sowing season that follows. Further, migrant labour from neighbouring states of Bihar and Uttar Pradesh has decreased (Sirhindi, 2019), and resulted in an increase in the cost of agricultural labour during the rice harvest season (Sharma,2018). Farmers find it both convenient and economical to burn residue to clear and prepare their fields for the next crop. In 2018, over 20 million metric tons of rice residue was generated in Punjab, of which almost 10 million metric tons was subject to open-air burning (MoA, 2019). The time window between rice harvesting and wheat sowing is just 20 to 30 days towards the conclusion of the Kharif season, which is one of the primary reasons of crop waste burning (Balwinder et al., 2016).

Floriculture and landscape architecture combine plant production with aesthetics, environmental improvement, recreation, and urban development. This chapter introduces the production, management, post-harvest handling, and marketing of flowers and ornamental plants. It also explains principles of landscape design, including balance, rhythm, harmony, colour, texture, form, space, and focal points. Softscape and hardscape components are considered in the planning of gardens, parks, institutional landscapes, roadsides, and urban green spaces. The chapter highlights the increasing importance of floriculture and landscape plants for urban biodiversity, pollution reduction, temperature moderation, recreation, and human well-being. Modern applications include turf management, green infrastructure, indoor plants, and peri-urban floriculture.

Horticultural crops are vulnerable to numerous insect pests, diseases, nematodes, weeds, and other biological stresses that can reduce yield and quality. This chapter presents integrated pest and disease management as a coordinated approach combining prevention, monitoring, cultural practices, biological control, mechanical methods, resistant varieties, and need-based chemical intervention. Accurate diagnosis and regular scouting are emphasized as foundations of effective management. Biorational products, pheromones, microbial pesticides, and natural enemies can reduce dependence on conventional pesticides. Responsible chemical use requires correct product selection, dose, timing, coverage, safety measures, and resistance management. The chapter promotes economically effective and environmentally responsible crop protection while safeguarding beneficial organisms, workers, consumers, and ecosystems.

Horticultural commodities are highly perishable because they remain physiologically active after harvest and are susceptible to moisture loss, respiration, microbial deterioration, mechanical injury, and physiological disorders. This chapter introduces principles of harvesting maturity, handling, grading, sorting, packaging, storage, transportation, and cold-chain management. Appropriate post-harvest practices help preserve freshness, nutritional quality, appearance, and market value while reducing losses. The chapter also examines value addition through processing, drying, preservation, packaging, and development of new horticultural products. Efficient post-harvest systems connect production with consumers and markets and are particularly important for high-value fruits, vegetables, flowers, spices, and other perishable commodities. Together, improved technology, quality management, and value addition can significantly increase farmer income and strengthen horticultural value chains.

Introduction

Soil organic matter is an indispensible component of soil health management. It plays an important role in improving soil physical, chemical and biological environment. Soil health refers to the capacity of the soil in terms of physical, chemical and biological properties for maintaining ecosystem services. With respect to agricultural lands, soil health implies the capability of the soil towards improving crop growth and yield, while also supporting environmental sustainability. Some important determining properties of soil health maintenance are soil reaction, salinity or alkalinity, soil organic matter, soil texture, soil structure/aggregation, water holding capacity, porosity, internal drainage, and nutrient retention capacity. Simultaneously, the key properties maneuvering soil health are soil aeration, internal drainage, nutrient cycling, susceptibility to erosion etc. Except some of the basic properties (soil texture) and processes (soil erosion), most of the determinant properties and processes are maneuvered by the presence of soil organic matter. A healthy soil must have strong resistance to degradation processes and able to recover following a perturbation because of inherent resilience (Magdoff 2001).

Nitrogen

Most commonly, complex organic compounds, ammonia, molecular nitrogen, nitrite, and nitrate are the forms of nitrogen found in soils. The physical and chemical conditions of the soil control the majority of the microbiological interconversions that change nitrogen.

Ammonia build-up, ammonia loss by volatilization, denitrification, nitrogen f ixation, and leaching losses of nitrogen are the primary changes that occur in submerged soils. The nutrition of rice is significantly impacted by these changes. Given the favourable circumstances for quick soil transformations and nitrogen loss, it is obvious that rice soils are nitrogen deficient.

Principle

β-Glucosidase (BG) plays a major role in the degradation of soil organic matter and plant residues. It catalyzes the hydrolysis of β-d-glucopyranosides, the final, rate-limiting step in the degradation of cellulose, the most abundant polysaccharide providing simple sugars for the soil microbial population. BG has been shown to be sensitive to changes in soil and residue management as well as an early indicator of changes in SOC before these changes are reflected in total or organic C analyses. The method is based on colorimetric determination of the p-nirtrophenol released by β-glucosidase when soil is incubated with buffered PNG solution and toluene.

8.1 The purpose of erosion research

The need for research

A soil conservation programme needs to be based on factual information about rates and quantities of erosion. For example some land obviously needs to be protected by mechanical works such as channel terraces, some land equally obviously does not need any protection, and a great deal of land lies somewhere between the two extremes. At some point the terraces become unnecessary or uneconomic, but a logical decision on where to draw the line can only be made if data are available on how much soil erosion is occurring and how much it would be reduced by terraces. Similarly, the effect of channel terraces should be compared with the effect of alternative measures, and the effect should also be measured on the different soils and crops which are likely to be encountered.

Nowadays there are excellent opportunities for research workers to exchange the results of their work. The national and iniernational journals are packed with accounts and results of research reports in their proceedings (as listed in Further reading). Some of the reported research results can be usefully applied in countries other than where the research was done, but care is required in any transfer of technology. If the local conditions of soil, climate, or land use, are different, the results may not apply. However, research in other situations can often serve as a pilot trial to show which factors should be studied locally. Even when local conditions are so different that the results do not apply at all, the techniques and apparatus developed by other workers can still be helpful.

7.1 The purpose and type of models

Sometimes the simplest way to estimate the effect of a physical process is to use an established equation, or formula, or charts and diagrams based on existing knowledge. The current fashion is to call such aids and solutions models, and they tend to become increasingly complicated and consequently dependent on computers to handle the mathematical processes.

It is important to identify the exact objective and purpose of models which are designed to estimate soil erosion. Two main divisions are models for prediction and models to assist with explanation. If the purpose is to predict amounts of erosion under alternative management practices then empirical models such as the USLE are efficient and effective. For an understanding of the processes of erosion it is necessary to turn to physically-based or deterministic models. The two objectives should not be cross-threaded onto the wrong kind of model, i.e. the USLE should not be seen as a vehicle for research studies on the mechanics of erosion. Neither should sophisticated simulation models be used as the basis for evaluating conservation practices which are better designed on the basis of experience, and evaluated by direct testing in the field.

The different kinds of models need a short explanation:

An empirical solution or model is one based on observation or experiment, and not derived from theory. It fits observed facts, and allows us to predict what will happen in certain circumstances, because we know what has happened before in those circumstances. The reliability of such methods depends on the database of experience: we might say This will certainly happen’ (because it always does), or “Will probably happen’ (because it usually does), or ‘it may happen’ (because it sometimes does). An empirical solution may be a simple approximate relationship or a complex multiple regression equation.

12.1 The nature of gully erosion

Gully erosion is spectacular and widespread, and so it is often used by conservationists as a characteristic symptom of erosion. As a result there is a danger of its importance being over-emphasized. Certainly it is most important as a source of sediment in streams, but in terms of damage to agricultural land or reduction of agricultural production, it is usually not very important for the simple reason that most land subject to severe gully erosion is of little agricultural significance. The really spectacular erosion so popular in non-technical reports shows large areas cut up by deep interconnecting gullies, but this situation is usually found in semi-arid climates unsuitable for any serious agriculture, or on soils which have such adverse chemical or physical properties that their potential production is very low. Added to this is the fact that gully control is always difficult and expensive, so the cost of reclamation usually exceeds the value of the land. Certainly in the sense of reducing the amount of eroded soil choking the dams and rivers it may be highly desirable to do something about gully erosion, but it is very much a case of prevention being better than cure. Limited resources in manpower, money and materials can usually be better employed in preventing future gullies than in curing existing ones.

The worldwide occurrence and recognition is well demonstrated in the variety of names: in English and American - gully, in Egypt - wadi, in South Africa - donga, in French-speaking lands - ravine, in India - nulla, in South America - carcava, or arroyo, and many others. The definition is the same in any case, a steep-sided eroding watercourse which is subject to intermittent flash floods. They are more common in semi-arid climates with infertile soils and sparse vegetation, but some spectacular examples are found in tropical forests in deep soils with dense vegetation.

5.1 Definitions

The erodibility of soil is its vulnerability or susceptibility to erosion, that is the reciprocal of its resistance to erosion. A soil with a high erodibility will suffer more erosion than a soil with low erodibility if both are exposed to the same rainfall. Whereas the erosivity of rainfall was shown in chapter 4 to be a fairly straightforward measure of the rain’s physical properties, the assessment of erodibility is more complicated because it depends upon many variables. There are alternative uses of the term erodibility. In the widest sense it can be used to include all the variables which effect erosion except the erosivity of rain, as in the first line of figure 2.2. It is also used in the narrower sense as a measure only of the effect of physical characteristics of the soil, as in the erodibility index K of the Universal Soil Loss Equation, where the effects of land management and crop management are assessed separately, as shown in the last line of figure 2.2.

5.2 Factors influencing erodibility

In this chapter we will look at the three broad groups of factors which affect erodibility. First, there are the physical features of the soil, including the chemical and physical composition. Second, there are the topographic features, such as the slope of the land. Third, there is the management of the land, i.e. how it is used.

6.1 Quantities and rates of runoff

Before a start can be made on the design of the channels and ditches and other works which can deal with surface runoff we need to know the probable quantity of water. If the object is to impound or store the runoff then it may be sufficient to know the total volume of water to be expected, but the usual conservation problem is conveying water from one place to another, and in that case the rate of runoff is more important, and particularly the maximum rate at which runoff is likely to occur. That is the flow which a channel must be designed to accommodate.

In a hypothetical catchment area* with an impervious surface and no losses the maximum rate of runoff would be directly proportional to the rate of rainfall. In natural catchments there are other factors: some of the rain is intercepted by vegetation, some infiltrates into the soil, some starts moving over the surface but is trapped in depressions, and some is lost by evaporation. Estimates of rates of surface runoff therefore depend on two processes: estimating the rate of rainfall, and estimating how much of the rainfall becomes runoff.

There are several empirical methods for doing both and for combining the two factors, but because they are empirical two points must be stressed. Firstly, as with all empirical solutions, data, tables, and formulae developed in one situation should not be applied in different conditions without careful checks on whether the method is valid in the new situation. Secondly, each of the three main methods which will be

Introduction

Modern agriculture has been of great help in alleviating hunger from the world, because the world population more than doubled itself during the last half of the 20th century; it increased from 2.5 billion in AD 1950 to 7.1 billion in 2012 (USCB, 2013). It is predicted that the world population will again double itself by the end of the 21st century and will touch the 12 billion mark. Most of this increase in population has been, and will be, in the developing countries in Asia, Africa and South America. India occupies 2.4 percent of the total land area of the world, but supports 16.7 per cent of the world population. Like many other developing countries in the world, population in India is increased from 345 million in 1947 to 1210 million as per the 2011 census with a growth rate of 1.76 during last decade. Therefore, pressure on land has been mounting up at an alarming rate. Population growth coupled with live stock population expansion, urbanization and industrialization are major contributory factors to it. The unscientific and unplanned exploitation of this limited resource takes its toll in terms of degrading the land. A large proportion of the land area shows clear evidence of advanced and continuing degradation seriously affecting the country’s productive resource base (Abrol and Sehgal, 1994). Jammu & Kashmir and  Nagaland  have maximum share of their land (94%) under degradation. This is primarily due to large areas under mountains, cold deserts and other such degraded lands. In the agriculturally prominent states like Uttar Pradesh (63%), Madhya Pradesh (50%) and Karnataka (46%) (Shalander Kumar, 2011) the extent of land degradation is of great concern and posing a big threat to the natural resources, resulting in almost 5 billion tonnes soil and 6 million tones of nutrient loss every year (Singh, 2009).

Introduction

The organic matter added to soil externally as FYM, crop residues, leaf fall, root deposition etc. has been a part and parcel of Indian agriculture. The total carbon added to soil is subject to microbial decay and slowly the major portion of it finds way back to the atmosphere. There is every possibility that atmospheric CO₂ concentration will increase in near future; that will further lead to increased attention of scientific community to make soil a possible sink for atmospheric CO2. when the carbon sequestration is thought with the perspective of reducing carbon dioxide emission for healthy atmosphere at one hand and improving soil health on the other, there is utmost need to opt for technologies that can fulfill both these objectives. There is growing interest in the use of charcoal or ‘biochar’ to sequester carbon in soil and improve soil fertility (Lehmann and Joseph, 2009). There are many types of soil additives and fertilizers used to improve the structure and functions of soil. Biochar has re-emerged as an issue in the last ten years as everyone is looking for sustainable ways to improve soils and decrease use of chemical fertilizers. 

Introduction

Climate change has undoubtedly resulted in greater public and scientific involvement. Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity (IPCC, 2007). The United Nations Framework Convention on Climate Change (UNFCC) defined it as a change of climate that is attributed directly or indirectly to human activity which alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods. World Meteorology Organisation defines climate change as statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). 

Introduction

Carbon on earth is stored primarily in rocks and sediments. Only a tiny fraction resides in mobile reservoirs – the atmosphere, oceans, soil and terrestrial biosphere – to play a vital role in biological, physical and chemical processes at the earth’s surface. The small fraction of C present in the atmosphere as CO₂ is especially important, as its abundance is a major regulator of the climate of the planet. The rapid increase in atmospheric concentrations of CO₂ over the past 150 years, reaching current concentrations of about 380 ppm, corresponds with combustion of fossil fuels since the beginning of the industrial age. Conversion of forest lands to agricultural use also redistributed C from plants and soils to the atmosphere and altered ecological balance through physiological effects on vegetation. The understanding of C sources and sinks has advanced enormously in the last decade. However, we cannot yet quantitatively define the global effects of human activities such as agriculture and forestry on climate change. An understanding on the long-term changes in atmospheric concentration will help enhance understanding on how the earth’s climate will evolve in future.

Introduction

Inappropriate land use and cultivation practices are one of the main reasons for the poverty and food insecurity faced by smallholders in most parts of the rural regions in India and other developing countries. Unsustainable agricultural practices lead to an exhaustion of soil resources, which results in reduced land productivity, aggravated land degradation, and a reduction in biodiversity. Conservation agriculture (CA),  has shown to improve, conserve and use natural resources in a more efficient way through integrated management of available soil, water and biological resources. It is now widely recognized as a viable concept for sustainable agriculture due to its comprehensive benefits in economic, environmental and social terms. Its ability to increase grain yields to provide better economic performance and reduce production risks and to improve energy use efficiency has been well-documented. 

Introduction

Indian agriculture is entering in a new phase. The major research and development efforts in the Green revolution era focused on enhancing production and productivity of selected food grains crops and only in Indo-Gangetic plains. The new challenges demand that issues of resource and input use efficiency receive high priority to ensure past gains can be sustained and further enhanced to meet the emerging needs. Issues of conservation have assumed importance in view of widespread resource degradation and the need to reduce production costs, increase profitability and make agriculture more competitive. The conventional mode of agriculture through intensive agricultural practices was successful in achieving goals of production, but simultaneously led to degradation of natural resources. The growing concerns for sustainable agriculture have been seen as a positive response to limit both low-input, traditional agriculture and intensive modern agriculture (relying on high levels of inputs for crop production). Sustainable agriculture relies on practices that help to maintain ecological equilibrium and encourage natural regenerative processes. Agricultural systems relying on such approaches are not only able to support high productivity, but also preserve biodiversity and safeguard the environment. Conservation agriculture has come up as a new paradigm to achieve goal of sustained agricultural production. It is a major step toward transition to sustainable agriculture.