eChapters

Abstract
India shares one fourth of global annual grain legume production and is also largest consumer of it. Weeds are the most severe and widespread biological constraint on agricultural production systems and cause damage to cropped and non-cropped lands. They reduce crop yield and degrade the quality of the produce, besides raising the cost of production. The grain legumesare commonly grown under rainfed/dry land conditions and hence do not receive the best management practices that are required for maximization of crop productivity. Among various production inputs, weed management was found to be the most important one contributing about 31% in pigeon pea, 110% in urdbean and 60 % in mungbean towards total productivity. Effective weed management in grain legumes is essential for optimizing
crop yield and quality. This process involves a multi-faceted approach that integrates cultural, mechanical, and chemical methods to address the challenges posed by diverse weed species and varying environmental conditions. Traditional single-method approaches often fall short due to the complexity and variability of weed problems like development of resistance in weeds. Therefore, an integrated weed management approach becomes effective, combining timely interventions with adaptive strategies to manage weed competition throughout the growing season. This approach not only enhances crop competitiveness and yield but also offers economic and environmental benefits by reducing reliance on broad-spectrum herbicides and promoting sustainable practices. Continuous monitoring and adjustment
of weed management strategies are crucial to effectively tackle evolving weed populations and changing conditions, ensuring long-term success in grain legume cultivation.
Keywords: Broad-spectrum herbicides, Crop productivity, Crop weed competition, Grain legume, Integrated weed management

Indian tea has a global reach being the second largest tea producer in the world. Indian tea is one of the finest in the world. Darjeeling tea is the first product to get a geographical indicator tag in India. 83 % of the tea produced in India is from Assam and West Bengal and 17% from the south Indian states of Kerala, Karnataka and Tamilnadu. Weeds are a major problem in tea gardens.

Weed flora

Drymaria cordata, Bidens pilosa,, Cynodon dactylon, Panicum repens, Celosia argentea, Ageratum conyzoides, Centella asiatica, Borreria hispida, Oxalis latifolia, Mikania micrantha, Paspalam conjugatum,

Rice is the primary food source for half of the Asian population. Nearly 2,000 million in this region obtain 60 to 70 per cent of their calories from rice and its products. Considering the importance of the crop, United Nations General Assembly declared 2004 as the “International Year of Rice” (IYR). In India, the crop covers one-fourth of the total cropped area. About half of the Indian population use rice as their staple food.

Rice based cropping systems are not only important for food security but also for maintaing an ecological balance. Low land rice fields conserve water and prevent runoff .They preserve the sustainability of the ecosystem.

With Judicious Use of Herbicides

Herbicides are the chemicals used for killing or suppressing the growth of weed plants from field / horticulture / plantation crops as well as non-cropped areas/ water bodies etc. The herbicide is said to be an ideal herbicide when it is very safe to the crop on which it is applied and on the other hand, it must control all associated weeds effectively. Also, ideal herbicides should leave no residual effects on the succeeding crop(s). Herbicides are of two types i.e.

1. Selective herbicides and
2. Non-selective herbicides.

A selective herbicide is that which is very safe to crop plants but unsafe to weed plants e.g. atrazine in maize, clodinafop in wheat etc. On the other hand, non-selective herbicides are those which kill all green plants including crop and weed plants which come in their contact e.g. paraquat and glufosinate ammonium.

Onion is highly vulnerable to weed competition because of its slow early growth, shallow roots, narrow upright leaves and limited canopy development. Weeds compete for light, water, nutrients and space while also harbouring pests and pathogens. Severe infestation during the critical competition period can cause substantial yield reduction. This chapter describes major onion weeds and evaluates cultural, physical, mechanical, biological and chemical control methods. Timely planting, suitable spacing, mulching, raised beds, manual weeding, mechanical tools, herbicides and biological agents are discussed. Integrated Weed Management is recommended as a smart approach combining complementary methods to improve weed control, protect soil health and sustain onion productivity.

Weed management in natural farming emphasizes natural, chemical-free methods that align with ecological principles. Instead of using herbicides or synthetic chemicals, natural farming promotes approaches that maintain biodiversity, improve soil health, and reduce weed pressure through various cultural, mechanical, and biological methods.
Here are key strategies for weed management in natural farming:
1. Mulching
Mulching is an agricultural and horticultural practice in which organic or inorganic materials are spread over the soil surface to protect and improve soil quality. In natural farming, mulching plays a key role by fostering a healthier ecosystem for plants without synthetic inputs.
Types of Mulch
Mulches are broadly categorized into organic and inorganic types:
• Organic mulch includes materials such as straw, leaves, grass clippings, crop residues, compost, wood chips, and sawdust. These materials decompose over time, enriching the soil with organic matter and nutrients.
• Inorganic mulch consists of materials like plastic sheeting, landscape fabric, and gravel. While these do not decompose, they effectively suppress weeds and retain moisture but do not improve soil fertility.

Symbolic to its nomenclature, ’PULSE’ (P = people, U = umbrella, L = livestock, S = soil and E = energy) is a superb group of agricultural crops extending an energy umbrella to people (as a major source of dietary protein), livestock (as a green nutritious fodder and feed) and soil (as a builder and restorer of soil fertility through biological N₂ fixation). On account of these qualities, pulses have occupied a unique position in the Indian farming system. Crop diversification with greater inclusion of legumes is essential to alleviate declining factor productivity, input use efficiency and increasing cost of cultivation for realizing sustainable use of natural resources. Pulses are increasingly becoming a component of the intensive cropping systems as intercrop, substitute crop or catch crop. In upland situations, pulses play an important role as intercrops and ensure more income and efficient use of resources. While analyzing the reasons of low productivity of pulses in various parts of the country, it is observed that non availability of high yielding disease resistant varieties, cultivation on marginal and sub-marginal lands under deficit moisture and fertility and poor pest management are the major constraints in realizing optimum yield potential.

Abstract
Legumes are an excellent group of fertility restorer crops which can be grown either as sole crop or as a component crop in the cropping system. As they are tolerant to drought condition, they can be grown throughout the year. The yield of legume crop is largely depending on pest, diseases and weeds. Among these weeds plays a major role as the weed seed bank inside the soil influence the weed population in the cropping season. Hence it is important to manage the weed seed bank for better productivity of legumes. Though legumes are short duration and fast growing crops, the germination percentage of weed seed bank will determine the final yield of legumes. There are many strategies to which the weed seed bank can be controlled to tolerable level before which the weed seed bank present in the soil has to estimate. Annual weed seed bank can be minimized by killing the weeds before they set seeds, harvest weeds, crop rotation, cover crops, inter cropping and ensiling. Weed seed bank depletion can be done by tillage, tricking the weed seeds, conditioning weed seeds, soil solarisation and herbicide application. Thus integrating various technologies may help in effective controlling of weed seeds to tolerable level thereby enhancing the yield of leguminous crops.
Keywords: Estimation of weed seed bank, legumes, tillage, yield, weed seed bank

Shifts or changes in the abundance and types of weeds within agricultural systems are common. These shifts can occur for a number of reasons and may result from cultural, mechanical, or chemical weed management strategies. The right combination of weeds and relying too heavily on any one practice is often the most common cause. Some of the concepts associated with weed species shifts are discussed below.

A weed shift is the change in the composition or relative frequencies of weeds in a weed population (all individuals of a single species in a defined area) or community (all plant populations in a defined area) in response to natural or human-made environmental changes in an agricultural system. Weed shifts occur when weed management practices do not control an entire weed community or population. Some species or biotypes are killed by (or susceptible to) the weed management practice, others are not affected by the management practice (tolerant or resistant), and still others do not encounter the management practice (dormant at application).

Those species that are not controlled can grow, reproduce, and increase in the community; resulting in a weed shift. Any cultural, physiological, biological, or chemical practice that modifies the growing environment without controlling all species equally can result in a weed shift. Weed shift may be due to introduction of new species or change in relative proportion of members of the existing community. Latter is the most common.

A. Species shift: Change in density of one or more species in field

B. Biotype shift: Change in density of biotypes within a species. These shifts often found noticed since biotypes typically are similar in appearance. Herbicide resistantbiotypes are the most frequently studied.

Weed monitoring is conducted to detect significant weed problems, rank them for relative severity and sort them by management type annuals, biennials, perennials, grasses and broadleaves. Weed monitoring provides information to tailor weed management efforts that reduce the impact of the weeds. The primary objective of weed survey and mapping is to accurately identify and delineate land with populations of unwanted plants. These surveys are conducted so that scientists and managers can predict those areas potentially subject to weed invasion; understand the biology of the invasion process and determine means by which weeds spread; develop, implement and evaluate weed management plans; assess the economic impact of weed invasion and increase public awareness, education and weed management efforts. Weed survey information is collected and compiled into maps showing the distribution and severity of infestation. Weed monitoring involves repetitive surveys to track weed populations over time. A standardized system of weed surveying and mapping is necessary to provide consistently reliable information that can be compared from year to year. Further, a standardized system allows weed survey data to be incorporated into a state wide weed survey database for the production of state wide noxious weed maps.

An agricultural weeder is a tool designed to remove weeds from fields or gardens. It can be used manually or attached to machinery like tillers and power weeders. Weeding is necessary to eliminate unwanted plants that compete with crops, ensuring better growth and profitability. Effective weed management is crucial in crop production, as weeds can reduce yields by stealing nutrients and attracting harmful pests. In recent years, research has focused on non-chemical methods and environmentally friendly alternatives to herbicides for weed control. Mechanical weeding is often the most cost-effective solution. Tools like rotary weeders, mechanical hand weeders, and wetland weeders are generally effective, with wetland versions gaining popularity due to their ability to function in shallow water. These tools uproot weeds and bury them in the mud through their pull-and-push action, making them both safe and eco-friendly. Weeding should be done at least three times during a growing season, with early weeding being the most effective for completely eliminating young weeds.
FUNCTIONS OF WEEDING EQUIPMENT
Secondary tillage equipment is often used for weed management. Weeders help control weeds between planted crops or before sowing. Some weeding machines use mechanical methods to remove unwanted plants without the need for chemicals.
Usage Instructions
• Early weeding is essential: Perform the weeding within 20 days after sowing.
• Delayed weeding can lead to competition between paddy and weeds, harming the crop.
• Move the weeding machine back and forth between rows.
• Conduct a second round of weeding after 15 days, and if possible, a third.

Origin of weeds : Weeds originated together with crop plants. They have been there since the man started cultivating crops about 10,000 BC. Man during his stage of development, explored certain crop plant to suit his own taste and fancy and cultivated them as ‘crops’. The unexplored / unwanted / troublesome plants which are interfering with his activities are considered as weeds. About 30,000 plants species have been identified as definite weeds in the World. Which are infesting crop lands, water bodies, gardens, orchards, road sides, railway lines, irrigation channels etc.

Plants are differentiated into

a) Crops: Which meet the needs of human being.

b) Weeds: Which compete or interfere in human affairs.

Jethrotull is the first person to use the word weed.

3.1. Cereals and millets

3.1.1. Rice

1. Major weeds

Grasses

Weeds are the plants growing where and when they are not desired. They compete with crops for soil moisture, nutrients, solar radiation and space, and thus reduce crop yields. Weeds also act as alternate hosts that harbour insect pests and diseases and other microorganisms. Some weeds release poisonous substances into the soil which may be harmful to crop plants, human and livestock. Weeds reduce the quality of marketable produce and render harvesting difficult, leading to increased expenditure on labours, equipment and chemicals for their removal.

Classification of weeds

A. Based on life cycle

Annuals-Complete their life cycle in a year or in a single growing season. Based on the season they may be summer annuals and winter annuals.
Summer annual e.g, Echinochloa crusgalli

Weeds are the plants, which grow where they are not wanted. Jethro Tull (1731) coined the word weed. Weeds can also be referred to as plants out of place.

Definition

Weeds are unwanted and undesirable plant that interfere with utilization of land and water resources and thus, adversely affect crop production and human welfare.

In organic agriculture weeds are treated as childrens of the soil.

In the world 30,000 species of weeds have been listed, of which nearly 18,000 cause serious damage to agricultural production. Eighteen weeds are considered as the most serious in the world and about twenty six species have been listed as principal weeds in crop fields of India, and are listed in annexure V

Introduction

Welding is a fabrication process in which two or more materials or metal pieces are joined or fused with the application of heat, pressure, or both allowing them to cool and this causes fusion. Besides the work piece, a filler material is also sometimes added to the joint to form a pool of molten material that cools to form a joint based on welding and that will be stronger than the parent metal.

Arc Welding and its Types

It is a process of joining two metals using an electric current generated by the power supply, which gives the required amount of heat to metal pieces through which the metals melt and when the metal cools, which results in the binding of the two metals. In the case of this type of welding, the power supply is given, which creates an electric arc between the electrode and the metal rod. Both A.C. or D.C. power supplies can be used in arc welding and both consumable and non-consumable rods can be used.

11.1 Introduction

The laws governing the flow of water in wells are referred to as the hydraulics of wells. Just like surface water flows from a higher elevation to a lower elevation by gravity, groundwater also flows from a region of higher water table to a region of lower water table. This difference of water table measured by any two piezometers divided by the longitudinal distance between them is called as hydraulic gradient. Hydraulic gradient plays a dominant role in deciding the flow of groundwater. This hydraulic gradient together with the hydraulic conductivity of the aquifer material forms the main law of well hydraulics called as Darcy’s law. An understanding of Darcy’s law together with some other laws as discussed subsequently in this chapter is essential in order to know the discharge of a well in a particular formation. Darcy’s law is valid for studying groundwater flow in alluvial formations. However, it is not valid for aquifers having hard rock areas.

Introduction

Wells are vertical shafts excavated or holes drilled in earth to the level of water table for extraction. Digging of wells is an age old practice. Shallow dug wells supported communities in the past. Well water is drawn to the ground manually or mechanically using variety of containers made of metal, leather, canvass and wood or a combination of them. Draught animals or electrical power are used to draw water for irrigation.

Water table (Fig.6.1) wells extend below the groundwater table and extract free water. Pumping water from these wells lowers the water level. The well first gains water from the water bearing material in its immediate proximity. Subsequently a cone of depression is formed in the immediate vicinity of the well. Water outside the cone of depression but with in the area of influence is diverted to replace the body of groundwater finding its way in to pumping well.

Pulses are recognized as an integral part of Bengali as well as Indian diet and the ideal supplement of cereals by virtue of their high protein and essential amino acid content.  Pulses are inseparable ingredients of vegetarian diet and one of the cheapest sources of dietary nutrition protein in the state. The present emphasis on soil health, environmental quality and economic consideration, has stimulated a paradigm shift in cropping patterns leading to pulse based cropping systems. Any cropping system can become compatible and complete only when a pulse crop is included in it. Pulses won a strategic position in intensive as well as subsistence agriculture, as they are excellent source of dietary protein for millions of people, nutritional feed for livestock and having profound ameliorative effect on soil.