eChapters

10.1. Introduction

The soils possessing characteristics that are not suitable and economical for crop growth are termed as Problem soils. These characteristics may be of physical, chemical and biological. For cultivation of crops in these soils, it is necessary to follow specific management interventions and proper reclamation measures. Frequently we come across another term, ’degraded soil’. Degraded soil is also a problem soil. However, there exists a hair-line difference between problem and degraded soil. Problem soils refer to the soils in which the inherent soil characteristics, obtained from its genesis, pose problems for their optimal use, while degraded soils are developed due to anthropogenic activities by unwise management interventions.

10.2. Types of problem

Mainly there are four types of problem that may exist in soils: physical problems, chemical problems, biological problems and nutritional problems as a result of physical, chemical and biological constraints in soils.

9.1. Introduction

Soil biology is a branch of science that studies the soil inhabiting organisms in relation to their ecology, functions, behaviour and impact on various soil processes and plant growth. Soil fertility is directly dependant on humus content as well as the presence of microorganisms in soil, although surface soil does not contain more than 0.5% by weight of living organisms. However, such a small portion of soil constituent as compared to other organic and inorganic constituents plays a significant and major role in transformation of plant nutrients from their unavailable to available form from organic wastes, soils and fertilizers. They have a direct role in improving soil tilth, providing an appropriate environment for root growth, decomposing organic residues to form humus and in turn releasing nutrients for plants use, releasing many plant growth promoters, fixing inert atmospheric nitrogen in plant usable forms and they promote many other important processes without which plants cannot survive. Absence of living organisms in soil leads to its infertility. An understanding of microbial processes in soil environment, keeping in view of soil nutrient status, carbon sequestration, soil health and quality, overall sustainability in agriculture and also global warming in respect of greenhouse gas emissions (nitrous oxide and methane) through agricultural practices, is very important in regulating nutrient release at different plant growth stages. If we are in a state to understand how various biological processes influence various changes in soil environment or in the opposite way that how different soil conditions alter the soil biota in number as well as in their functions and diversity, it is easier to implement soil management practices that promote to gain more benefits.

Microorganisms are ubiquitous in nature. Possessing a diverse habitat, they are found everywhere in soil, air and water at a varied temperature and pH. One may find the highest genetic diversity of life within the domain of microorganisms. But unfortunately very few are known to us, so far only 1% of the microbial species on the earth are culturable. However, it is believed that soil of one gram may contain hundreds of millions to billions of microbes which may represent several thousand microbial species. In respect of the population, bacteria top the list followed by actinomycetes, fungi, algae and protozoa in accordance with a decreasing numerical order. Out of three important soil fertility components viz. physical, chemical and biological; the biological component is least understood due to its wide complexity.

8.1. What is an ion exchange reaction and its application in soil system

Ion exchange is a reversible chemical reaction between two substances, either between two electrolytes or between an electrolyte solution and a solid complex as well as between two solid phases (if in close contact with each other), where ions of equal charge may be interchanged in equivalent proportion.

Organic colloids and inorganic micelles (clays) are sites of ion exchange. Soil contains silicate clay minerals which exhibit charges due to isomorphous substitution as well as due to the pH dependant charges for ionisation of hydrogen and hydroxide functional groups. Organic matter present in soil also contributes to the pH dependent charges due to the presence of various active functional groups. Thus, the organic and inorganic colloids present in soil bear positive or negative charges. Electric charge on soil particles is neutralized by equivalent amount of oppositely charged exchangeable counter ions, held by coulomb forces and van der Waals forces. Ca⁺², Mg⁺², H⁺, K⁺, Na⁺, NH₄ ⁺, Al⁺³, Fe⁺³, Fe⁺², Mn⁺², etc. are the common cations present in soil where Ca⁺² serves as the dominant ion. However, Na⁺ and Al(OH)₂ ⁺ are the dominant cations found in the exchangeable phase in strong alkali and strong acid soils, respectively. SO₄ ^- 2, Cl^-, HCO₃ ^-1, NO₃ ^- etc. are the most common anions found in soil to neutralize positively charged soil colloids.

7.1. Introduction

Like all other living organisms such as humans, animals, and microorganisms, plants also need elemental nutrients for their growth and development. They assemble the nutrients from soil, water and air. However, to obtain economical crop yield, nutrients are also supplied to the crops from external sources such as chemical fertilizers and manures and using biofertilizers. It is the present-day need to handle the soil fertility status in a more realistic and careful way to obtain maximum crop harvest. Under poor management practices, soil may become infertile and loose its importance in agricultural use. In modern days, huge food demand for the burgeoning human population does not permit to show luxury to use only fertile soil. Moderately fertile soil or even degraded soil should also be managed properly so that they may be used to grow crops. For this, plant nutrients status of the soil plays a significant role along with other soil properties. For sustainable soil fertility management, parameters such as crop to be raised, its nutrient demand at various growth stages, current nutrient status of the soil, amount of nutrient application based on the soil testing results etc are important to be considered. Balanced nutrition to the plants is the prerequisite to obtain maximum benefit. If nutrients supplied to the plants are low in quantity than their requirement, crop production is lowered down. Similarly, if the nutrients are provided in more amount in the soil or unbalanced way through fertilizer or manure applications, total crop yield is suffered. It is a very common example that excess of phosphorus leads to zinc deficiency in most crop plants and it has been observed that excess N is responsible for potassium starvation in potato. Again, excess of iron, manganese, zinc, copper shows plant toxicity. Addition of nutrients to soils in excess also causes environmental pollution when the excess nutrients are lost from soil by leaching, surface run-off and volatilization. Unscientific way of soil fertilization leads to increasing cost of cultivation and imparts adverse effect to the environment instead of doing any good. Therefore, one should have a clear knowledge on soil fertility to obtain a sustainable productivity.

6.1. What is colloid and colloidal system?

A colloidal particle may be defined as a substance which is microscopically dispersed evenly throughout another phase and is possessing a size of 10^-7 to 10^-3 mm and representing a larger surface area per unit mass. Thus, a colloidal system refers to a two-phase system in which small particles of one phase which might be of solid, liquid or gas is suspended evenly in the second phase of solid, liquid or gaseous material. These colloidal systems may be of solid in liquid or solid in gas or liquid in liquid or liquid in gas. Unique examples of liquid in liquid colloidal system includes the fat droplets dispersed in water of milk. When you put floor disinfectant liquid in water, it forms a white emulsion. Thus, emulsion becomes a colloidal system of liquid in liquid. Likewise, in fog, water droplets are suspended in gaseous air. So, fog is an example of a colloidal system, constituting of liquid dispersed in gas. When we refer smoke, it contains carbon particles (solid) suspended in air (colloidal system of solid and gas). However, smog is composed of smoke and fog. In case of soil colloidal system, soil colloids, which are of tiny particles (<0.001 mm size) and may be of organic and inorganic nature, are suspended in soil solution (water) and referred to as sol. Colloidal chemistry, which involves in the surface reactivity and charge characteristics of colloids, plays a pivotal role in total soil chemistry.

5.1. What is soil organic matter?

Plant and animal residues which are not yet added to the soil are considered as organic materials. However, once they are added to soil, they become soil organic matter. Therefore, organic materials contributing to the soil matrix are referred as Soil Organic Matter (SOM). Sometimes SOM is also used to highlight only the non-living organic materials produced by living organisms. But SOM should be regarded as a broad term that includes biomass, partially decayed residue, and highly decomposed and transformed organic substances, humus. Agricultural soil contains nearly 1-5% of SOM, which is regarded as least amount in soil as compared to other three soil components, minerals (45%), air (25%) and water (25%). However, it contributes enormously to soil productivity. Soil productivity and fertility exhibit direct positive relationship with SOM content in soil. Plants and animals are considered as primary and secondary sources of soil organic matter, respectively. Plant residues and application of organic manures e.g., farmyard manure, compost or green manuring help to build up organic matter in soil and thus, enrich the soil with organic carbon and other plant nutrients. Under natural conditions, roots of grasses in grasslands, the leaves including shoot portion of the large trees in forest lands and after harvesting the crop remnants in agricultural field provide enough incorporation of organic materials in soil. SOM plays a vital role to maintain sustainability in agricultural production through producing healthy soils and thus, healthy crops.

4.1. What is pH?

pH is used to classify substance as acidic, neutral and alkaline, based on the prevalence of free H⁺ ions. Water molecules on autoionization dissociate to produce H⁺ and OH^- in equal number, although degree of dissociation is very small because of its stability (about one molecule in 10 million is ionized at any one time). H⁺ ions later attached to un-ionized water molecule to give rise hydronium ions, (H₃O)⁺

3.1. What is weathering?

Weathering may be defined as the transformation process of solid rocks, involving the disintegration and decomposition of rocks and minerals, into soil.

There are different types of weathering: physical, chemical and biological.

3.1.1. Physical weathering

In physical weathering the chemical composition of the weathered products remains same as that of the parental rocks. It is involved in fragmentation of rocks into comparatively smaller sizes. It does not transform the parental rock into a newer one that may differ from the parental rock in chemical composition. The process is totally physical in nature. But this is also true that physical weathering encourages chemical weathering, and both may be carried out simultaneously because physical weathering promotes more surface area of parental rocks for more interaction with agents of chemical weathering.

2.1. Minerals

Primarily, minerals are usually inorganic substances possessing a definite chemical composition and a definite molecular arrangement which is usually expressed in geometric form. The mineral matter is made up of various elements, combined to form compounds. Usually, minerals consist of more than one constituent elements. Quartz contains two elements, silicon and oxygen. Other minerals may contain many elements, such as amphibole consists of several elements that include sodium, calcium, magnesium, iron, aluminium, silicon, and oxygen. Some elements exist as such without forming compounds. They contain exceptionally one element. Graphite (C), diamond (C), and Sulphur (S). Minerals are naturally occurring crystalline solid where the atoms are arranged in a regular three-dimensional array. A crystal is a solid, formed by a repeating three-dimensional pattern of atoms, ions, or molecules & possessing fixed distances between the different parts. Minerals that do not grow in these regular or crystalline patterns are called amorphous solids. When we talk about ‘naturally occurring’, we exclude the laboratory-synthesized crystalline solids. Glass and amber are also naturally occurring solid, but they are not crystalline and thus, they are not considered as minerals, rather they are referred as amorphous solids.

1.1. What is Earth?

The Earth is a layered body consisting of three parts: core, mantle, and crust. The radius of the Earth is nearly 6370 km of which crust, mantle and core share a depth of 40, 2850 and 3480 km, respectively (Figure 1.1). Exterior of the Earth contains the outer lithosphere which is surrounded (70% of surface) by water (hydrosphere). Solid and liquid sphere are surrounded by gas (atmosphere). The atmosphere is of 320 km above the lithosphere / hydrosphere. It is believed that there is a progressive increase in temperature with depth, if one goes to the core from the Earth crust. There is a rise of approximately about 1°F for every 64 feet depth on an average. Therefore, one could imagine that the interior of the earth is in molten condition.

The farming of striped murrel is quite old in many south-eastern and south Asian countries including India under traditional farming system. Wee (1981) has given an account of traditional farming of striped murrel in Thailand, where seed of wild stock was stocked in very high density (75-460 numbers/m²) in ponds. Freshwater small fish (FSF) were fed to the seed during pre-monsoon and monsoon seasons and subsequently marine small fish (MSF) mixed with rice bran to satiation level. The fish grew to 700-1000 g in 7-10 months with an FCR of 6.5:1 and production of 9.0-15.6 kg/m². In another culture trial, Diana et al. (1985) have described a poor survival of 9-13%, when they stocked seed @ 40-80 number/m² collected from wild sources and fed them on FSF for 9-11 months. There are records of backyard production of this species also (Wan et al., 1992). The major problems with traditional farming were poor & uncertain survivals, problems of getting SFs and occurrence of diseases due to poor management protocols.

Therefore for a scientific farming of this species, the major bottlenecks are the non- availability of hatchery seed, species & size specific feed, cannibalism at all stages and disease occurrence. These bottlenecks have been addressed to a greater extent by the researchers in recent and protocols for hatchery seed production and cannibalism reduction have been simplified to a greater extent with the availability of commercial pellet diets to boost its farming. Vietnam has been pioneer in the production of farmed striped murrel in recent, following new initiatives and based on its success, neighbouring countries such as Indonesia, Camobodia, Thailand, Myanmar, etc have also taken initiatives to boost production of this high value species in their countries.

Stocking fingerlings in grow-out ponds increases survival rates, cut-down culture duration, better feed management and reduce risk-factors on account of natural as well disease occurrence. In pond culture, good amount of fry-size seed suffer predation from enemies such as snakes, birds and predator fishes, if any and mortalities due to disease occurrence as smaller size fish is more vulnerable. However, fingerling stocking reduces predation loss to a greater extent, increase survivals, allow better feed management and highe production. This is truer with carnivorous fishes and particularly those observe cannibalism. Qin and Fast (1996) stated that the rate of cannibalism is higher in small size (TL) predators than the larger in case of striped murrel, so stocking large size fingerling in culture ponds reduces chances of ICC and hence recommended for grow-out production.

7.1 Traditional Methods of Fingerling Rearing

Wee (1981) has defined traditional system of murrel farming in Thailand in which seed of murrel was procured from wild resources and raised to large fingerling size before stocking. Two type of practices being used to raise fingerlings. In the first one, the pond(s) designated for fingerling production are stocked with brooders of SFs so they could spawn in the stocking pond(s) few days before the stocking of striped murrel fry and could directly feed upon the juvenile SFs. In second system, the fingerlings were reared to accept small-size fish (SF) along with rice bran to cut down cost of feeding on production of fingerling. In recent, more systematic approaches have been made to wean the seed collected from the wild resources on inert diets totally. The protocol adopted for weaning the fingerling on inert diet includes initial feeding with cut pieces of SFs and then gradual supplementation of inert diet till fingerlings start relishing inert diet completely.

The objective of larval rearing is to mass-produce high-quality and healthy juvenile fish. In larval rearing, the management of both rearing environment and feeding regime are the most important aspects. Improving larval rearing technique requires understanding of larval morphology & behaviour and requirements of live food, artificial diet and environmental conditions at different ages of larvae (Liao et al., 2001). Striped murrel is predatory as well cannibalistic species in nature. Therefore understanding about its behavior with respect to feeds and feeding, stocking density with growing age is utmost important. It is a general thinking that fish hatchlings do not require exogenous food until yolk-sac attached to their body is exhausted. But this is untrue with many carnivorous fish species, particularly those observe cannibalism. Larvae of such fish species start feeding much before the yolk-sac absorption; rather delay in getting feed make them weak or force them to feed on the conspecifics. Therefore in order to understand larval behavior of this species in respect of feeds and feeding, knowledge on its ontogenic development is crucial particularly in respect of age at which mouth opens; mouth gape size, food choice, size of food particle at different age-groups and finally the age when gut digestion starts.

Yulintine et al. (2017) have given ontogenetic details of striped murrel larvae since hatching. According to him, mouth opens and exogenous feeding begin in this species when hatchling grows to a size 4.63+0.25mm on second say of hatching. On day-3 after hatching, the buccopharynx channeled with the anterior intestine through a short oesophagus and rather narrow lumen, with having prominent liver developed by this time. Two pyloric caeca appeared on day-25 hph, indicating the transition from larval to juvenile stage and acquisition of an adult type of digestion. This chapter provides strategy for larval rearing of striped murrel based on ontogenic studies and work carried out by various workers in this field including that of authors.

Predation and cannibalism are entirely two different processes. In predation, the animal used to consume other species then their own, whereas cannibalism is a practice of eating one’s own kind. Cannibalism is a common behavior in animal kingdom and has been recorded in more than 1500 species. It is reported in an increasing number of fish species belonging to group/ families such as air-breathing catfishes (Clariidae), pikes (Esocidae), percids (Percidae), characids (Characidae), latids (Latidae), gadids (Gadidae) and in over 30 other families, including cyprinids (Cyprinidae) and salmonids (Salmonidae) (Smith & Reay, 1991; Hecht & Peinaar, 1993; Folkvord, 1991; Baras, 1998; Qin et al., 2004). Cannibalism is a common ecological interaction and depends on genetics and fish behavior; mediated by appetite and metabolism and is promoted by size differences, and is more intense among fast growing larvae and young juveniles than among older fish (Hecht and Pienaar, 1993; Baras, 1998).

Cannibalism is a serious problem in the farming of striped murrel that starts from the early larval stage (Ng and Lim, 1990) and continues at all sizes including during parenting also. Murrels have large mouth gape; sharp jaw teeth for catching & grasping prey and can consume prey fish more than half to two-third of its length (Wee, 1981; Diana et al., 1985; Ng and Lim, 1990 and Qin and Fast, 1996). Its aerodynamic body shape allows fast movement in water and catching the prey with ease. Striped murrel observes two types of cannibalism, Filial and Intracohort, which is discussed in detail in the subsequent sections.

In order to get assured supply of quality seed weaned on formulated diet, the captive spawning is the right choice for successful farming of striped murrel. Captive spawning involves several activities such as broodstock development, induced breeding, hatching of eggs, larval rearing, etc. These activities are given in detail in the following sections.

4.1 Broodstock Development

Brood stock development is an integral part of captive breeding programme in fish and the success of breeding largely depend on it. It involves rearing of healthy brooders of both sexes in captive conditions to meet the targeted production of seed. In striped murrel, maturation of gonad begins in the first year of their life. However, brooders of 2⁺ year age or above are better and recommended for captive breeding (Pati et al., 2004). A size of 400g to 1500g is considered ideal (Fig. 10). Brooders may be procured from wild sources or reared on-farm from farm-raised fingerling. Brooders from wild stocks are to be procured at least 2-3 months prior to spawning season so that they acclimatize to the farm conditions. It is recommended to give them a bath of 50 ppm formalin for about 8 hours under vigorous aeration before stocking in the tank/pond. Formalin treatment removes external pathogens from the fish body. Brooders raised at the same farm do not require formalin treatment, if they are free from any wound.

3.1 Spawning Season

Striped murrel breeds in stagnant waters and commence breeding in ditches, ponds, tanks, flooded paddy fields, wetlands and dead end of rivers; a little prior to or with the onset of monsoons (Bhattacharya 1946; Chacko 1947). Striped murrel is a batch spawner species and hence breeds several times in a year. According to Courtenay et al. (2004), spawning occurs in this species all through the year. In northern states of India, the breeding season of this species coincides with south-west monsoon and extends from June to September with peak in mid of June to mid of August (Qasim and Qayyum, 1961). However, the species has been reported to breed during November to January in southern India (Alikunhi, 1953).

Knowledge on fish reproductive biology is extremely important to understand various issues relating to reproduction and fishery management. Reproductive success in aquaculture systems depends to a greater extent on our knowledge about sexual differentiation, gonad structure, gametogenesis, spawning, larval metamorphosis, etc for successful captive breeding of a fish species. This chapter therefore, contains information on secondary sexual characters, sex-ratio, gonad structure, gonadal maturity, fecundity and embryonic development of striped murrel.

2.1 Secondary Sexual Characters

The sexes are separate in striped murrel however differentiation of sex is not easy when fish is immature. The differentiations in sexes become distinct with advancement of maturity during spawning season. On attaining full maturity, a good fecund mature female could be easily distinguished with having bulged belly originating nearing the site of pectoral fins and extends near to the vent.

The species is commonly found in tanks, ponds, lakes, reservoirs, canals, swamps, etc in freshwater plains. It is air-breathing in nature and survives easily low oxygen stress. During drying-up of water bodies in summers, it has been reported to penetrate deep under moist-earth and come out live on arrival of rains. The name 'murrel' encompasses its resemblance to reptile (snake) due to presence of body scales all over its body including head region. Fully-grown adults are dark greenish brown with faint black and white vertical bands visible across its entire abdominal length below the lateral line and a black ocellus at posterior end of dorsal fin.

Striped murrel is one of the important food fish of high commercial value due to preference for its meat quality, therapeutic and antinociceptive properties and hence consumed by many to induce healing and pain control after clinical operations. It contains high arachidonic acid (AA), which is a precursor of prostaglandin that may initiate blood clotting and enhance tissue growth. Geographically, the species is distributed in Western to Southeast Asia including Bangladesh, Cambodia, China, India, Indonesia, Lao People’s Democratic Republic, Malaysia, Myanmar, Nepal, Pakistan, SriLanka, Thailand and Vietnam (Chaudhary, 2019). It is supposed to be introduced in countries like Fiji, New Caledonia (Welcomme, 1988), Madagascar (Stiassny and Raminosoa, 1994) and Hawaii (Courtenay et al., 2004). The species has been reported to grow to a length of 100 cm (Rahman, 1989) and categorized„ Least Concern under the IUCN Red List (IUCN, 2020).

Globally, 92523 ton of striped murrel is produced (FAO, 2016), of which the major share of 70802 ton is contributed from capture fisheries and 21721 ton from aquaculture (Figure 1). Though capture fisheries of striped murrel is quite stable in terms of global production, the aquaculture has shown a steady rise in last two decades. In India, though no production data is available, the production of this species is mainly contributed from the capture fisheries with meager contribution from aquaculture. This has caused serious stress in past few years on its resources, more particularly due to habitat degradation and man-made hazards in aquatic ecosystem.

ABSTRACT

The rapid growth in population has created the need of industrialization and as a result there has been a significant increase in milk production and processing. Milk is a commodity which is consumed by persons of all age groups due to its nutritive value and health promoting attributes. However, the rapid growth in dairy sector has adversely affected the environment by emitting various greenhouse gases and thereby, resulting in global warming. Apart from it, there has been an increased usage of non- renewable resources like natural gas and coal in dairy sector. As a result, a viable balance has to be maintained between milk production and processing, environmental health and the rapidly growing population. This can only be achieved with the application of green or environment friendly technologies in all the stages of milk production and processing. This chapter will mainly deal with the various sources of greenhouse gases from dairy sector and on application of life cycle assessment and carbon foot printing for computing the impact of greenhouse gases on the environment. Also, this chapter will enclose various green technologies which can be applied in dairy sector to curb the greenhouse gas emissions.

Keywords: Carbon footprint, LCA, Greenhouse gases, Green Technology, Milk production, Milk Processing

ABSTRACT

Banana plants areextensively known for their fruits butby-products (pseudostem, root, leave, male banana flower, and banana peel) from banana farms also have potential applicability because recycleprocess of these wastes can convert waste of banana farms into an outstandingresource of valuable raw materials for other industries. This practice avoids huge losses of unused biomass and environmental hazards. Banana flowers are discarded in banana farms during the harvesting of banana fruit bunches and produce a great amount of agricultural waste. Consumption of banana flower as a vegetable is trendy in some parts of Asian countries but the cleaning process of banana flower is an unwieldy practice because of the time and the laborengaged in separating the calyx and the pistil portion of these flowersbefore processing. Itis an abundant source of well-balanced essential amino acids, unsaturated fatty acids, dietaryfiber, vitamins, minerals,and flavonoids. This flower also having tremendous medicinal properties as they possess several secondary metabolites. Thepresent review discusses the transformation of this agricultural waste into a different value-added product. The transformation of banana flowers into highly commercial outputs can be beneficial forsupplementary income to small scale farming industries.

Keywords: Banana, Banana flower, By-product, Value-added product, Antioxidant, Pre-treatments, Processing.