eChapters

3.1 Introduction

India is rich in biological diversity as revealed by its floristic diversity comprising 17,926 species of angiosperm, based on which it has been considered one among the 17 mega-biodiverse countries of the world. Also, it is the centre of some of the oldest civilizations of world, starting with Vedic civilization. Using modern day scientific tools and technology backed up with shashtra pramaana, Vedic civilization has been calculated to be as old as 25000 years (Oak, 2018). Because of its rich ecological and biological diversity, Indian Subcontinent has inhabited a large amount of ethnic diversity, consisting of both the indigenous races and those moved from other parts of the world as settlers looking for greener pastures for better living. The major ethnic races are Caucasoid (Aryan), Dravidians, Mongoloid, Negroid, and Australoid. Anthropological Survey of India has identified 461 tribal communities (Xaxa, 1999), belonging to 227 ethnic groups (Pushpangadan et al., 2018) spread over 5000 forest villages. According to the 2001 census of India, the country has 122 major languages and 1599 other languages. Figures from different sources vary, primarily due to differences in definition of the term’s “language” and “dialect”. The largest of the language families represented, in terms of speakers, is the Indo-Aryan language family followed by the Dravidian language family.

The capacity of soil to function as a vital living system, within ecosystem and land use boundaries, to sustain plant and animal production, maintain or 

enhance water and air quality, and promote plant and animal health (Doran and

Zeiss, 2000). A healthy soil may function is as follows:

• Sustain biological activity, diversity, and productivity

• Regulate, store of nutrients and cycle water and, decompose organic

matter

• Filtering and buffering, degrading, mineralizing, immobilizing, and

detoxifying organic and inorganic materials

• Inactivate toxic compounds, suppress pathogens, protect water quality,

and enhance catchment soil health.

Introduction

Climate change is threatening food security globally. Countries like India are more vulnerable in view of the tropical monsoon climate and poor coping capacity of the small and marginal farmers. Several agricultural practices like indiscriminate use of agro-chemicals and crop residue burning contribute to emission of greenhouse gasses leading to warming of the atmosphere. Sequestration of carbon both in the vegetation and soil is the most effective means of mitigating GHG emissions. There are several strategies of soil carbon sequestration which can be adopted at farm level. These include: conservation agriculture, biomass recycling, crop rotations and use of organic amendments. One of the recent developments is the conversion of crop residue biomass into biochar and using the char as a soil amendment rather than directly using the crop residues. Several studies show that biochar has a long life in soil and is more effective in sequestering carbon besides improving other soil properties like water holding capacity and nutrient availability. In Indian conditions, there is an immense scope for converting millions of tonnes of crop residues which are not used as fodder into biochar and use the same for enriching soil carbon.

Introduction

Productivity has increased as a result of the significant industrialization that has occurred in India during the past 40 years. However, it has also had detrimental effects on the ecology, particularly in India where soil contamination is progressively becoming more severe. In addition to the effects of man and land use, soil is constantly adapting changes in environmental conditions. A characteristic of soil pollution is the decrease in soil productivity brought on by the presence of soil pollutants. Some changes in the soil will be temporary and reversible, while others will be permanent. Pollutants in the soil have a negative impact on the physical, chemical, and biological characteristics of the soil and decrease its production. Soil pollution is a result of a variety of factors, including pesticides, fertilizers, organic manure, chemicals, radioactive waste, abandoned food, clothing, leather goods, plastics, paper, bottles, tins, and corpses. Industrial waste contains chemicals including iron, lead, mercury, copper, zinc, cadmium, aluminum, cyanides, acids, and alkalis, among others, which either directly or indirectly enter the soil.

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).

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).

Introduction

Microbial diversity is one of the main factors characterizing natural ecosystems; soil is considered one of the best storehouses of useful microorganisms in the world. Although the role of most of these microorganisms is still unknown, scientific progress is providing a better comprehension of the specific ecological functions of soil microorganisms (Ahmad, I.et al., 2008). Microorganisms in the rhizosphere soil play a key role in maintaining the soil fertility (Yadav et al. 2015), which is key for successful natural crop production to meet the increasing global organic food demand. Soil acts as a reservoir of air, water, and nutrients that is essential for plant growth. Only a few grams of soil contain hundred million to billion microorganisms. Bacteria are the most abundant microbes in soil followed by fungi; however, the actinomycetes are ranges in between bacteria and fungi. Other microbes that are found in smaller numbers are algae, cyanobacteria, protozoa, and nematodes. Soil gives the necessary support for anchorage to plant roots (Yadav et al. 2012; Bhaduri et al. 2015).

Introduction

Ideal plant health and productivity of a cropping system depends on an adequate amount of plant nutrients. Fertility of the soil refers to its capacity to support the production of crops. A productive fertile soil can support optimal plant growth, seed germination to plant maturity by providing adequate soil volume for plant root development, essential plant nutrients to meet the nutritional requirements of the plants, and encourage for the consequent plant structure. These attributes of the soil can be distinguished as inherent or dynamic soil quality indicators.Optimum plant health and productivity of a cropping system depends on an adequate supply of plant nutrients. The quantity of nutrients required by plants varies depending on many interacting factors including:

• Agronomic effects

• Soil properties

• Climatic condition

• Management practices

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.

Introduction

At a present time, Organic farming has an important priority in different areas due to worldwide in look of the growing need for pure and nutritious agriculture food and keep up the feasible and environmental pollution on long time associated with indiscriminate use of chemical fertilizer. The use of synthetic inputs in crop cultivation is necessary to meet the growing need for agriculture food in world. The natural fertilizers are made containing living or veiled cells or their strains of N2 fixation, P2 O5 solubilization bacteria. The biofertilizers are used for seed cramming, soil or vermicomposting region with the objective of rising quantity of such microbes and further those microbial processes which augment the obtainability of nutrients that can be easily digest by plants. Biofertilizers are playing higher role in increase soil productivity by f ixing atmospheric nitrogen, both, in relationship with plant roots and without it, solubilise and insoluble soil phosphorus and produces many plant growth substances in the soil.

Introduction

Manures are obtained from the plant residues, green manure, compost and animal wastes that are used as source of plant nutrients. They release nutrients after their decomposition. They essentially function as sustenance to the crops. They help in the proper cultivation of crops. The addition of manure enables the soil to hold more water. Organic manures have acids that dissolve the nutrients in the soil and make them available to the plants. manures can be grouped into bulky organic manures and concentrated organic manures. Brief dissection about manure given blow flow chart.

Bulky Organic Manure

Bulky organic manures are those materials of plant and animal origin, which contain small percentage of nutrients when added to the soil have tendency to decrease bulk density and to increase soil volume, thus providing better physical conditions for plant growth especially in coarse textured soils and also provide essential nutrients in smaller quantities than the chemical fertilizers. Characteristics of bulky organic manures:

Introduction

Problem soils are those that impede agricultural productivity owing to mineral stress, dryness, acidity, sodicity, waterlogging, etc. Vertisol, acid sulphate soils, saline-sodic soils, peat soil, and fine textured alluvial soils were the categories Beek et al., (1980) used to group the problematic soils. In addition to vast areas where deficiencies of zinc, phosphate, and iron, or excesses of iron, aluminium, and manganese limit rice yields, Ikehashi and Ponnamperuma (1978) observed that approximately 100 million hectares of land that are physiographical and climatically suitable for rice lie idle due to the soil toxicities caused by salt, alkali, acid, or organic matter. Problem soils can be broadly defined as those that have unfavourable conditions whether natural or artificially created that severely restrict the successful development of crops. Soil profiles with high groundwater levels and a less permeable argillic layer, degraded soils, sandy soils with low fertility, coastal soils that frequently flood, and laterites could all be categorised as problem soils. Without taking into account related soil functions, soil health is evaluated independently. It is also based on the f indings from a few soil tests for different criteria. 2015 has been recognized the International Year of Soils by the 68th UN General Assembly in recognition of the importance of soil health in all dimensions.

Introduction

 Salinity is a form of salt that occurs naturally within soils or water. When soil

becoming salty form that is called salinization, it can be caused by mineral

weathering called as natural process but it can be caused by irrigation called

as artificial process. Saline or salty soil have a high salt content like sodium

chloride (NaCl also called table salt). Salinity is like- abiotic stress for plants

and reduced the plant growth but not for all because some of them crops are

survive in better way for growth and development such as barley, sugerbeet,

cotton and mustard etc. Basically, stress are two types-biotic and abiotic

stress. Abiotic stress are also called nonliving stress like- drought, salinity,

submergence, heat, cold and temperature that are affect to plant life cycle so

that are called as abiotic stress. Natural water and all types of soil both contain

soluble salts. Amount of salt affected to weather of soil, when excessive salt

present in soil and it adversely affects to crop growth and developments. Salt

affected soils exist under arid and semi-arid climates. Major constitutions of

soluble salt in soil are the cations and anions. Cations are containing sodium,

calcium, magnesium and anions are contains chloride, sulphate, carbonate and

bicarbonate. Saline soil have <8.5 pH, >4EC (dS/m) and <15 ESP. where EC

is eclectical conductivity that is measure of soil salinity and ESP stand for

Exchangeable sodium percentage.

Soil pH

 Soil reaction is measured by pH (Puissance de Hydrogen) of a suspension of

soil in water. The word “pH” has originated from the French word “pouvoir

hydrogen” which means powers of hydrogen. The acidity, neutrality or

alkalinity of a soil is measured in terms of hydrogen ion activity (active

concentration) of the soil water system. Most of the agricultural soils have

a pH varying from 4.5 to 8.5. The active concentration of hydrogen ion is

termed as ‘active acidity’ which is 1/50,000 or 1/1,00,000 times lesser than the

exchange acidity or exchangeable hydrogen.

 Soil pH is a measure of the activity of ionised H (H+) in the soil solution. The

pH of a solution can be defined as the negative logarithm to base 10 of the H+

ion activity or the logarithm of the reciprocal of the H+ ion activity.

pH = -log10

 a[H

 +] = log10

 1/[H

 +]

 There is difference between activity and concentration. Activity and

concentration are related by the mathematical expression

 a

 c

 F

 = where a = activity of a species (moles L-1)

 c = concentration of that species (moles L-1), f = activity coefficient

 a = c for dilute solutions, f = 1

 Activity coefficient of an ionic species is the degrees of freedom of that species

to participate in an equilibrium reaction or to maintain its charge under an

ionic environment.

Introduction

 India, situated between the latitude of 08004’ and 37006’ N and longitudes of

68007’ to 97025’ E, has a geographical area of 329 Mha. Physiographically, it

can be divided into three broad regions, viz., Peninsula (a triangular Plateau in

the Deccan and South of the Vindhyas), Mountain region of the Himalalayas

(Extra-Penninsula), and the Indo-Gangetic Plain separating these two regions.

Geologically, a great part of the Penninsula is occupied by the gneiss, schists

and other rocks of diverse nature. Red soils (Alfisols) generally predominate in

this region. The western and central parts predominate in basaltic rock having

Black cotton soils of different thickness (Vertisols, Inceptisols). The mountain

region shows the development of marine sediments of all ages, especially, in

north of the Himalayas. The vast Indo-Gangetic and other plains of Pleistocene

origin are composed of alluvium of the great river systems flowing in this

region. The alluvial soils of this region depend on the age of alluvia and degree

of development.

Climatically, India shows three distinct seasons:

 i) Cool and mainly dry winters from November to February

ii) Hot and mainly dry summers from March to June

iii) Monsoon rainy season from mid-June to September.

Introduction

Soil resource catalogue provides an insight into the capability and the constraint

of mapped area for its optimum exploitation towards developmental planning.

For this motive soil survey series as an essential tool. Soil survey is essentially

a study and mapping of soils in their natural environments and systematic

examination, description, classification and mapping of soil of area.Soil survey

contains a group of compound operation involving

•             To study important properties of soils and associated land features.

 •            Define taxonomic units through correlation and classifications of soils.

•             To establish and draw a border of different kinds of soils on standard

topographical base map through mapping of soils.

 •            Transfer of technology from research farm to farmer ‘s field under

different soil condition and management practices.

Cation Exchange of Clay Minerals in Soil

The term “clay mineral” refers to phyllosilicate minerals and to minerals which impart plasticity to clay and which harden upon drying or firing. Clay minerals are layer silicates that are formed usually as products of chemical weathering of other silicate minerals at the earth’s surface. Clay minerals in soil play a significant role in exchanging cations, which are positively charged ions, and in regulating soil fertility and nutrient availability. Cation exchange capacity (CEC) is a measure of a soil’s ability to exchange cations and is influenced by the type, abundance, and charge properties of clay minerals in the soil. Clay minerals have a high CEC due to the presence of charged surfaces (silanol and alumoxane groups) that can exchange cations with the soil solution. The most common cations exchanged by clay minerals are hydrogen (H+), calcium (Ca2+), magnesium (Mg2+), potassium (K+), and sodium (Na+). When a soil solution comes into contact with clay minerals, cations in the soil solution are adsorbed or attracted to the charged surfaces of the clay particles.

Introduction

Soil aeration status involves the rate of such ventilation, as well as the proportion of pore space filled with air, The composition of that soil air and the resulting chemical oxidation or reduction potential in the soil environment. Water provides the base for food, nutritional and environmental security. Soil water plays a significant role in controlling the energy balance of the soil and its overlying micro-environment by modifying its radiation exchanges and thermal properties. Soil temperatures affect plant and microorganism growth and also influence soil drying by evaporation. It is a central maximum of ecology that “everything is connected to everything else.” This interconnectedness is one reason why soils are such fascinating and challenging objects of study. In this chapter we shall explore three aspects of the soil air, water and temperature.

Introduction

The interest in soil as a natural body originated from its ability to produce and sustain crops. The scientific study of soil probably started in the mid-nineteenth century and was dominated by geologists, chemists and plant physiologists. Justus von Liebig (1840) in his famous publication, Chemistry Applied to Agriculture and Physiology, put forward the theory that plants assimilate mineral nutrients from soils which varied in their capacity of nutrient supply. The ‘Law of Restitution’ propounded by him states that whatever is being taken by plants from the soil needs to be restored to maintain the nutrient supplying capacity of the soil.

Statistics: Collection of methods for planning experiments, obtaining data,

and then organizing, summarizing, presenting, analyzing, interpreting, and

drawing conclusions.

Sir R.A. Fisher: Father of modern statistics.

Population: All subjects possessing a common characteristic that is being

studied.

Sample: A subgroup or subset of the population.

Parameter: Characteristic or measure obtained from a population.

Statistic: Characteristic or measure obtained from a sample.

Karl Pearson: Study of correlation and chi-square test of goodness of fit.

W.S.Gosset: Student’s t-test for small sample

Francis Galton: Regression analysis.

Descriptive Statistics: Collection, organization, summarization, and

presentation of data.