eChapters

13.1. Storage pests

13.1.1. Rice weevil: Sitophilus oryzae, S. zeamais, S. granarius

1. Host range: Wheat, rice, maize, sorghum, paddy.

Introduction

Most of the technological advances in the recent past in Indian Horticulture have been done for favourable agro-climatic regions. However, the vast and diverse land-scape of hot desert, arid, semi-arid and tribal area is not yet receiving logical thought for resource based horticultural development (Samadia and Haldhar, 2017). Although, the semi-arid regions of the country have now became potential hub for aonla, bael, ber, pomegranate, jamun, guava, fig and custard apple. There has been a steady increase in area and production of these fruits particularly under aonla, ber, custard apple and pomegranate in the country as a result of identification and development of suitable varieties and production technologies. The average productivity of these fruits in India is, however, low as compared to many developed countries. The main reasons for low productivity are old and senile orchards, low yielding varieties, poor orchard management and inadequate technological up-gradation and adoption by the growers. Presently, the continuing decline in the availability of cultivable land, rising energy and land costs together with the increased demand of fruit and fruit products, have given thrust to the concept of high density planting (HDP) in fruit crops. High density planting gives earlier production and return per unit area, shortens juvenility, eco-friendly, provides efficient land use and better use of resources like light, water and fertilizers, efficient pesticides application, besides, in this system the harvesting becomes easy(Mishra and Goswami, 2016). Among the factors such as cultivar, rootstock, quality of planting material and cultivation practices contribute to high yield of fruit trees, however, the number of trees^-1 is the most important factor which brings about radical increase in fruit production. Therefore, high density planting has great potential for increasing productivity in fruit crops (Mishra et al., 2003). The success of this technology in most of the fruit crops is dependent on the use of methods to control shoot growth and maximize light interception as the trees begin to bear fruit. The main aim of HDP is to achieve the twin requisites of productivity by maintaining a balance between vegetative and reproductive growth without impairing the plant health and fruit quality. The underlying principle of HDP is to make the best use of vertical and horizontal space per unit time and to harness maximum possible return per unit of inputs and natural resources.

Introduction

According to the Forest Survey of India (FSI) “all lands, more than one hectare in area, with a tree canopy density of more than 10% is defined as Forest” (FSI 2009). The status of forests and forest management systems contribute to the vulnerability of forests to climate change. Indian forests are extremely diverse and heterogeneous. Forests and Climate Change are intimately intertwined. Forests have regulated the climate, rain, groundwater, soil of the earth over millennia. Their transpiration act as a regulator of the balance of oxygen and carbon-di-oxide: the world’s forests and forest soils currently store more than one trillion tons of carbon – twice the amount found floating free in the atmosphere. The forest and soils are home of biological diversity.

Check dams are small water control structures designed to slow down water flow and limit erosion, particularly in hilly or mountainous regions where other flow regulation methods may not be feasible. The suitability of a site for check dam construction depends on factors such as terrain gradient, soil characteristics, and the potential for enhancing groundwater recharge. Locations with flat or mildly sloped land and stable soil conditions for a solid foundation are generally ideal. These dams function as multi-purpose solutions, playing a vital role in water regulation and soil preservation. Their importance extends across hydrological, ecological, and social aspects, making them key components in sustainable infrastructure efforts.
WHAT ARE CHECK DAMS?
Check dams are small structures constructed across shallow rivers or streams to harvest water. These barriers help retain excess monsoon water in a small catchment behind them. The pressure buildup in this area pushes water into the ground, aiding groundwater recharge. This stored water, both on the surface and below, is primarily used for irrigation during and after the monsoon but can also serve domestic and livestock needs. They vary in size and are made from materials such as clay, stone, or cement. Earthen check dams can be easily built by farmers, whereas masonry and RCC (Reinforced Cement Concrete) dams require skilled labor and higher costs. Earthen structures typically do not allow overflow, unlike RCC and masonry dams which include spillways for excess water.
Construction of a Check Dam
Used as an engineering solution to prevent soil erosion in vulnerable areas, check dams reduce water speed, trap sediments, and sometimes only consist of an embankment. Initially, a water body forms behind the structure, which gradually fills with silt.

A chute spillway is a type of spillway that uses an open channel to convey excess water from a reservoir to a lower level, typically through a steep slope. It’s essentially a concrete-lined, open channel that allows water to flow at supercritical velocities. Design considerations include inlet and outlet structures, channel geometry, and ensuring the channel can contain the design flood discharge. Also known as a trough spillway or waste weir, is an open channel structure designed to safely convey excess water from a reservoir down a steep slope, typically to prevent damage to valley walls and ensure the structural safety of dams. It is particularly well-suited for earthen dams, where integrating a spillway within the dam body is not feasible, unlike ogee spillways, which are commonly used in concrete gravity dams.
The spillway usually consists of a steeply sloping, open channel constructed with reinforced cement concrete (RCC) slabs, typically 25 to 50 cm thick, with light reinforcement (approximately 0.25% of the concrete area). For economic efficiency, the channel is often narrowed in the central reach and widened at the downstream end to reduce the velocity of discharge and control erosion. Key structural features include:
• Watertight expansion joints to accommodate temperature variations and concrete movement.
• Under-drain systems to manage seepage under the base and sidewalls.
• A slope steep enough to maintain supercritical flow, avoiding unstable hydraulic jumps.
Chute spillways can be constructed:
• At the end of a dam (flank weir),
• In a natural saddle separated from the main dam by a ridge (saddle weir),
• Along dam abutments, depending on the topography.

Laboratory analysis is an important part in any branch of chemistry and analytical chemistry in particular. To undertake the analysis, both apparatus and equipments are needed.

The study of construction materials involves analyzing the properties, applications, and performance of various substances used in building structures. These include traditional and modern materials such as concrete, steel, wood, stone, clay, composites, insulation, and finishing materials. The selection of appropriate materials is guided by factors like structural requirements, costeffectiveness, durability, environmental conditions, and sustainability goals.
Construction materials play a critical role in determining the strength, functionality, and longevity of a structure. They may be natural, such as wood and stone, or synthetic, such as plastics and reinforced concrete. The intended use of the building, local climate, and project budget heavily influence material choices, making their careful selection a key component of successful construction planning and execution.
Materials are the literal building blocks of construction, defining the essence of a structure from its durability and efficiency to its aesthetics and environmental impact. Each material has inherent properties and potentialities, making the selection process integral to the design and construction phases.
NATURAL MATERIALS
Natural materials like stone and wood are among the earliest and most foundational elements used in construction. Stone is exceptionally durable and naturally abundant, making it a preferred choice since ancient times. Its high compressive strength, resistance to fire, and ability to withstand weathering ensure long-term structural reliability. Additionally, stones such as granite, limestone, and marble offer aesthetic appeal, symbolizing strength, elegance, and permanence in architectural design.
Wood, another vital natural resource, is prized for its versatility and strengthto- weight ratio. It can support substantial structural loads while remaining

Soil conservation structures are physical or biological interventions designed to prevent soil erosion and degradation. These can range from basic, non-cultivated strips of land to advanced, engineered systems. Their primary role is to safeguard soil health, reduce surface runoff, and support the sustainability of agriculture over the long term.
Soil conservation as a broader practice involves adopting effective land management techniques to preserve soil quality, fertility, and productivity. It plays a vital role in sustaining crop yields, protecting natural ecosystems, and upholding overall environmental integrity.
Soil is fundamental to life on Earth, serving as the basis for agriculture, supporting biodiversity, and playing a key role in climate regulation. Despite its importance, soil faces growing threats from erosion and degradation, demanding urgent and focused action.
This section explores the critical role of soil conservation, outlines various strategies to maintain soil health, and examines the obstacles encountered in implementing these practices effectively. Understanding the significance of preserving soil is essential— not only for farmers but for the sustainability of the entire planet.
SOIL CONSERVATION
Soil conservation refers to the implementation of practices aimed at preventing soil degradation while preserving its fertility and productivity. It encompasses a variety of methods designed to minimize erosion, prevent nutrient depletion, and maintain soil integrity. The central aim is to keep soil fertile for agriculture and to support broader environmental functions, such as ecosystem balance and water regulation.

A drop inlet spillway is a hydraulic structure designed for soil and water conservation, particularly effective in areas with significant elevation changes such as gullies and ravines. It safely conveys excess water from reservoirs, embankments, or other structures to downstream channels, thereby preventing overtopping, erosion, and structural damage. The spillway consists of three main components: an inlet, a vertical conduit, and an outlet. Water enters through the inlet, drops vertically through the conduit, and then flows horizontally into a downstream channel via an outlet. This design is especially suitable for controlling gully heads and stabilizing gully beds. Typically, drop inlet spillways are constructed at fixed intervals across the gully width to form a series of control points. These structures help to dissipate flow energy, reduce erosion, and promote sediment deposition, gradually filling the gully section. Although effective, their use is generally limited to vertical drops of up to 3 meters. Drop inlet spillways play a crucial role in reducing land degradation and enhancing water management in erosion-prone areas.
COMPONENTS OF A DROP INLET SPILLWAY
A drop inlet spillway is composed of several key components that work together to safely and efficiently convey excess water while minimizing erosion and structural damage. The primary components include:
• Inlet Structure: This is the entry point where water enters the spillway. It can have various configurations, including circular or rectangular box-type flat crests or the more commonly known funnel-shaped morning glory crest.
• Vertical Shaft: A central conduit that allows water to drop vertically from the inlet down to the outlet level, utilizing gravitational force to convey flow.
• Outlet Conduit: A horizontal or inclined pipe or tunnel that transports water from the base of the vertical shaft to the downstream channe

A drop spillway is a type of structure used to release extra water from a dam or reservoir. It is characterized by a steep or nearly vertical drop in the water channel, which allows excess water to be discharged safely while reducing its energy. The main components of a drop spillway include a crest or weir at the top, a drop section for the falling water, and a downstream channel equipped with energy dissipation features to control erosion. The suitability of a site for a drop spillway depends on factors such as the terrain, soil stability, and flow conditions.
A spillway in general is designed to release surplus water from a reservoir once it reaches its storage limit. Water usually flows over the spillway during flood situations, when the inflow exceeds the dam’s capacity. Typically located at the top of the reservoir, a sphelps prevent water from overtopping the dam. In addition to spillways, some dams have bottom outlets controlled by gates or valves to release water. In cases where there is no overflow spillway, dams may rely entirely on these bottom outlets for flood control.
DEFINITION OF SPILLWAYS
A spillway is a structure that enables the controlled release of water from a dam or levee to flow downstream, usually into the original riverbed. Before examining its different types, it’s essential to understand why a spillway is necessary for dams.
A spillway acts as a channel to safely discharge surplus floodwater once a reservoir reaches its full capacity. Every dam is equipped with a spillway as a critical safety feature. Spillways can be integrated within the dam itself, positioned at its edge, or constructed as separate entities. It is essential that the spillway has adequate capacity; an undersized spillway could cause the dam to overflow, potentially leading to severe damage or complete failure of the dam.

Bunding is a traditional yet effective soil conservation method that involves constructing embankments or barriers along land contours to manage water flow and reduce soil erosion. These embankments, known as bunds, are particularly beneficial in semi-arid and erosion-prone areas, where water conservation and soil stability are essential for sustainable agriculture.
Bunds slow down surface runoff, allowing water to infiltrate the soil rather than washing away valuable topsoil. This not only reduces erosion but also improves soil moisture retention and supports crop growth. Bunds can be made from local materials such as soil, stones, or a combination of both.
TYPES OF BUNDING
There are several types of bunding, each with its unique features and benefits. Let’s explore the most common ones:
Contour Bunding
Contour bunding is a well-established soil conservation technique that involves constructing embankments along lines of equal elevation across sloping terrain. These structures, often equated with level terraces, are designed to intercept surface runoff, thereby reducing soil erosion and improving moisture retention in cultivated lands. Originating as a famine relief initiative in Maharashtra, India, contour bunding has since proven to be an effective and sustainable method for preserving agricultural productivity in hilly and semi-arid regions.
This practice is particularly suited to a wide range of permeable soils, including alluvial, red lateritic, shallow and medium black soils, as well as deep black cotton soils. However, challenges such as soil cracking in black cotton soils may compromise bund integrity, necessitating periodic repair and upkeep.

Terrace farming is a widely practiced agricultural method in India, particularly suited for hilly and mountainous areas. It involves shaping the landscape by carving out flat sections—known as terraces—into the slopes of hills or mountains. These levelled surfaces make it easier to cultivate otherwise steep and challenging terrain. This age-old technique, also known as step farming, creates a series of stepped platforms that resemble a staircase along the hillside. The approach is both practical and resourceful, allowing farmers to use sloped land efficiently for crop cultivation.
The primary motivation behind transforming large hill surfaces into terraces— despite the considerable labor it demands—is to control the rapid downhill flow of water that typically occurs in such regions. However, terrace farming comes with its own set of challenges. The soil on terraces often has limited water retentioncapability, and erosion can become more severe. Nutrients and soil particles tend to be washed away into rivers. In addition, if trees are cleared for farming, the land becomes vulnerable to landslides and mudslides during periods of heavy rainfall. Terrace farming is a prevalent agricultural practice in India, especially in regions characterized by hilly or mountainous topography. This method involves the creation of flat, horizontal plots—referred to as terraces—along the natural contours of slopes. These terraces transform steep, uneven land into cultivable platforms, making farming on such terrain more manageable and productive. Also known as step farming due to its resemblance to staircases carved into hillsides, this traditional technique is both efficient and adaptive. It enables the utilization of sloped land that would otherwise be unsuitable for agriculture. The primary reason for undertaking this labor-intensive process is to manage the rapid runoff of water common in elevated terrains. By interrupting the slope, terraces help slow water flow and reduce surface erosion. Nevertheless, terrace farming poses several challenges. The soil tends to have limited capacity to retain moisture, and erosion can still displace vital topsoil and nutrients. Furthermore, deforestation to create terraces can heighten the risk of landslides and mudflows during intense rainfall.

Introduction
A study protocol tool is a very important comprehensive document that deliberately outlines the whole research rationale design and plan for the successful execution of the epidemiological/ an experimental/ a clinical study. It serves as a blueprint for how the study will be conducted, ensuring consistency, transparency, and adherence to ethical guidelines. The document contains the background information available in literatures on the basis of which the researchers plan to conduct the study with objectives that will answer research related questions with ensuring adherence to ethical standards.
Basic Elements of a Study Protocol
The study protocol includes different components including background Information available in literature for research plan, objectives or purpose of conducting the research, explanation of the study design, selection and exclusion of subjects, treatment of subjects, assessment of outcome safety and efficacy. The purpose of conducting research includes questions like why the study needs to be done and what will be its relevance to scientific society or environment. To achieve these objectives the researchers, design their research work for proper execution of research objectives. The study which is to be designed has structured framework for researchers to answer their research questions and obtain reliable and valid results. The study design not only helps the researcher in learning technical skills but also discovering the creative voice (planning and execution). The study design includes different methods, processes and necessary resources for accomplishment of research problems. The study design also incorporates the methods of data collection and statistical analysis which meets the requirements of desired outcome. The implementation of an appropriate study design guarantees a methodical and exacting research process, resulting in more precise findings and the appropriate type of analysis to address the research-related queries. This makes the conclusions more reliable and legitimate. By ensuring that the data are reliable, repeatable, and validated, a well-designed study contributes to the advancement of knowledge. Additionally, it helps to control biases and confounding variables that could affect the results and helps to clarify the methodology of the study, which

Microbial transformations of sulfur (S) are even more complex than those of nitrogen because of the large number of oxidation states of S and the fact that several transformations of S also occur abiotically. Although a number of oxidation states of S are possible, only three are significant in nature, 2 (sulfhydryl, R–SH, and sulfide, HS-), 0 (elemental sulfur, S0), and 6 (sulfate, SO₄ 2-). The bulk of S Earth’s S is in sediments and rocks in the form of sulfate minerals, primarily gypsum (CaSO₄) and sulfide minerals (pyrite, FeS2), but the oceans constitute the most significant reservoir of SO₄ ^2- in the biosphere. A significant amount of S, in particular sulfur dioxide (SO₂), enters the S cycle from human activities, primarily the burning of fossil fuels.

Hydrogen Sulfide and Sulfate Reduction

A major volatile S gas is hydrogen sulfide (H₂S). Hydrogen sulfide is produced from bacterial sulfate reduction or is emitted from sulfide springs and volcanoes. Although H₂S is volatile, different forms exist depending on pH: H₂S predominates below pH 7 and the nonvolatile HS- and S^2- predominate above pH 7. Collectively,H₂S, HS, and S₂ are referred to as “sulfide.” Sulfate-reducing bacteria are a large and highly diverse group and are widespread in nature. However, in anoxic habitats such as freshwater sediments and many soils, sulfate reduction is SO₄ ^2- limited. Moreover, because organic electron donors (or H₂, which is a product of the fermentation of organic compounds) are needed to support sulfate reduction, it only occurs where significant amounts of organic material are present.

Sulphur (S) occurs in soil in both organic and inorganic forms. Inorganic S fraction may occur as sulphate (SO₄^2-) and compounds of lower oxidation state such as sulphide (S^2-), polysulphide (S_n^2-), thiosulphate (S₂O₃^2-) and elemental sulphur (S⁰). In well drained soils inorganic S usually present as sulphate. Under anaerobic condition (reduced or waterlogged soil) inorganic S mainly occur as sulphide and under extreme condition as elemental S form. Estimation of S carried out in two steps:

Sulphur (S) occurs in soil in both organic and inorganic forms. Inorganic S fraction may occurs as sulphate (SO₄^2-) and compounds of lower oxidation state such as sulphide (S^2-), polysulphide (S_n^2-), thiosulphate (S₂O₃^2-) and elemental sulphur (S⁰). In well drained soils inorganic S usually present as sulphate. Under anaerobic condition (reduced or waterlogged soil) inorganic S mainly occur as sulphide and under extreme condition as elemental S form. Estimation of S is carried out in two steps:

1. Extraction of different forms of S from soil by suitable extractant.
2. The filtrate is then analysed for S by the turbidimetric method.

The turbidimetric method is the most widely used one because of its simplicity and rapidity.

Sulphur in nature follows similar cycle as that of nitrogen and shares many common features with it. In soils, decomposition of organic matter releases major portion of nitrogen and sulphur bound in proteins, as cystine or methionine amino acids, or vitamins, etc. In proteins, on an average, for every 36 atoms of nitrogen one atom of sulphur is present. Mineralization supplies a large fraction of nitrogen and sulphur to the plants. Secondly, both nitrogen and sulphur have several chemical forms under different soil conditions (Table 8.1) and both are subject to microbial reduction. Thirdly, both can enter or leave soil in gaseous form and both are subject to some degree of leaching in the anionic form.

4.1 Determination of Specific Surface Area of Soil

Specific surface area of a soil is defined as surface area per unit weight of soil and is expressed as m² g^-1. The specific surface of soil greatly influences the physical and chemical properties such as retention of water at high suction, swelling, plasticity, soil strength, cation exchange capacity and availability of nutrients. The basic principle of determination of specific surface is based on the amount of gas or polar liquid required to form a monomolecular layer on the soild. Knowledge of molecular size (diameter) and the mass of the adsorbate enables one to calculate specific surface of the adsorbent.

Principle

Dyal and Hendricks (1950) introduced a method for estimating specific area based upon the adsorption of ethylene glycol (EG) to form a monomolecular layer over the entire soil surface. The method involves adding EG to pretreated soil or clay sample and evaporating the excess EG in an evacuated system. The quantity of EG retained at the moment the evaporating rate decreases is proportional to the surface area. Later on Carter et al. (1965) suggested the use of ethylene glycol monoethyl ether (EGME) having high vapour pressure at room temperature than EG for determining surface area of the layer silicate minerals and soils.