eChapters

4.1. INTRODUCTION

Dispersion is the extent to which values in a distribution differ from the average of the distribution. To quantify the extent of the variation, there are certain measures namely:

1. Range
2. Quartile Deviation
3. Mean Deviation
4. Standard Deviation

Range and Quartile deviation measure the dispersion by calculating the spread within which the values lie. Mean Deviation and Standard Deviation calculate the extent to which the values differ from the average.

Introduction

Desert soils are the soils of arid regions that remain dry for most part of the year and support sparse xerophytes. The amount of water received by precipitation is far less than what is lost by evapotranspiration. Most deserts receive an average precipitation of less than 400 mm. Because of extreme imbalance between evapotranspiration and precipitation, many desert soils contain salts.

Distribution

Deserts occupy about one-third of the areas of Africa and Australia, 11% of Asia and about 8% of the Americas (Boul et al. 1997). Desert soils include both cold and hot desert. In India, desert soils occur in three agro-ecological regions (AER). The cold arid desert of extreme north (Leh, Ladakh region of Jammu & Kashmir ), the hot arid desert of north western India (Rajasthan, southern parts of Haryana and Punjab and northern parts of Gujarat) and the tropical arid desert of the Deccan plateau in South India represents AER 1, 2 and 3, respectively. The three different desert regions in India have characteristic climatic and soil conditions.

Introduction

Low and erratic precipitation, diurnal fluctuations in temperature and low humidity are the typical characteristics of deserts and their margins. Further, strong winds, sunny and very bright days and unpredictable periods of drought and famines are regular features. These lands are poor in fertility. Uninterrupted increase in human and animal pressures is violating carrying capacity of the natural resources, thus resultant is desertification.

Arid zones are described as a part of the drylands, and have the most severe edapho-climatic conditions. The major distinguishing feature for defining and for planning for the arid zone is the low rainfall (below 500 mm or Aridity Index <0.20) with more than 50% inter-annual variability. This makes a great difference in terms of the nature of the ecosystem, the socio-economic environment and the challenges for sustainability. High wind and solar regimes further increase the effect of rainfall variability and the whole complex makes a fragile ecosystem in which small disturbances may cause great loss to the sustainability, which are sometimes irreversible (Hou’erou, 1996). The hot arid zones of the world are economically and environmentally disadvantaged, with unique problems. The ecosystems of these zones are highly fragile with large risks that cause severe impediments to development programs. Of the total land area in the world, arid zones cover 18.8% and the hyper-arid zones account for 22.3% of the total arid zones (FAO, 1989).

Abstract

Burkina Faso is a landlocked country in West Africa with a dry tropical climate characterised by a short rainy season and a long dry season. The annual rainfall varied between 300mm in the northern part of the country to 1200mm in the meridian part. Since many years, the degradation of climatic conditions is observed. Therefore, the annual rainfalls of the 1971-1981 period were inferior to those of the precedent periods, and also the deterioration of the climatic conditions led the limits of some ishoteques “isohyète” to move southward, more than 50km farther. Furthermore, the decennial rainfalls since 1920 were subjected to a latitudinal displacement to the south. For example the ishoteque “isohyète” 500mm which were located at the North of the 15°N outside Burkina Faso during the years 1950-1960 moved gradually year by year and reached the 14°N during the years 1970-1980 inside Burkina Faso.

Abstract

Conversion of an already arid land into a desert through indiscriminate human actions magnified by droughts. Such actions include overgrazing, repeated burning, intensive farming, and stripping of vegetation for firewood. One quarter of the earth’s surface is threatened by desertification - an area of over 3.6 billion hectares. Since 1990, Six million hectares of productive land are lost every year due to land degradation. Desertification threatens the liveihoods of more than one billion people and has already made over 135 million people homeless. Desertification does not occur in linear, easily mappable patterns. Deserts advance erratically, forming patches on their borders. Areas far from natural deserts can degrade quickly to barren soil, rock, or sand through poor land management.

Concept and Definition

Desertification is a major problem in the drylands of India, affecting the way of life for its inhabitants. The problem is more severe in the arid lands in the northwestern part of the country. There have been a few numbers of definitions of the word “Desertification”. However for simplicity of its origin and meaning we would refer to two of the frequently used ones; (1) proposed in 1991 by UNEP: “Land degradation in arid, semi-arid and dry sub-humid areas resulting mainly from adverse human impact and (2) prepared for the Earth Summit at Rio, held in June 1992, for inclusion in Agenda 21, as “Land degradation in arid, semi-arid and dry sub-humid areas resulting from climatic variations and human activities. (Anonymous 1992).

Comparing two of these initial definitions, it would show that first one indicated desertification as a state of natural resources like soil and vegetation, mainly resulting from human activity while the second one included climate as a major cause. However, it reduced the emphasis of human activities as being the primary responsible factor and tried to link the possible impact of climate change on desertification. But the simplicity of the 1992 definition of desertification helped researchers to bring in sharp focus on the special environmental and socio-economic problems of the drylands.

So over the years, the key words that explains the term “desertification” has been changing or are being amended for specific purposes. This would at least mean that the problem of desertification is still debated world-wide, and its impact is not limited to some nations/regions as was presumed and discussed in first of UNCCD platforms. Therefore, as a precaution and combating this process, few catchy words like non-sustainable management, productivity, over-exploitation of natural resources, dryland livelihood, droughts are found to surround the word desertification. Earlier, some, people equated desertification with advancing boundaries of the existing desert and in India, examples of expansion / contraction of geographical boundary of Thar desert was a public debate among various researchers and planners. In the same time, some of the definitions tried to broaden its geographical scope so that greater populations suffering from adverse effects of land degradation would benefit out of various remedial measures.

Introduction

Desertification is now accepted as a major environmental issue because of the fact that 69.5 percent area of the world’s dry lands and more than 1.2 billion people in over 110 countries living in this habitat are affected by various land degradation processes. During last 20 years, researchers have focused their discussion either on a condition or a cause or a set of processes to assess different paradigms of desertification. Several studies carried out in arid western part of Rajasthan (Singh et al., 1992, Kar, A. 1993b, Kar, 1995, Dregne, H.E. 2000, Kar et al.2007) show that wind erosion is still a major problem. Though, there are many instances of location specific problems like water erosion, salinity/ alkalinity and water logging, about 75% area in arid western Rajasthan is affected by wind erosion hazard of different intensities (SAC, 2007, Kar et al. 2009). Decreasing rainfall gradient from east to west and increasing wind strength in that direction are responsible for the spatial variability in sand reactivation pattern. Water erosion in the form of sheet, rill and gully erosion is a major problem in areas, where average annual rainfall exceeds 350 mm, the rainfall intensity is high and the topographic and soil characteristics favour high run-off. Destruction of vegetation cover and excessive ploughing of shallow soils, especially on the sloping lands, accelerate the problem.

Introduction

Desertification, which is considered a major threat in the drylands of the world, is not about advancing boundaries of the existing deserts, but about land degradation in the arid, semi-arid and the dry sub-humid regions, which together form the drylands (Anon., 1995). Secular variation in climate that has resulted in periodic expansion and contraction of the desert boundaries and regional-scale changes in vegetation condition (Tucker et al., 1991; Nemani et al., 2003; Hickler et al., 2005) is one of the drivers of desertification. Human activities constitute the other major driver. According to Geist and Lambin (2004) the prominent core variables that drive degradation are climatic, economic, institutional, national policies, population growth and remote influences.

We let you know that the type of people in a given region is closely linked to the kind of resources found in the concerned region; and which are necessary for human beings to survive.

In fact, more than 100 countries possess arid lands, where more than 40% of the global population lives. The soils of these regions present too much fragility and they are too degraded that they can’t allow people to survive.

Let’s emphasize that in Africa, two third of the total area are arid zones. Thus, for Africans, the type of their struggle for adaptation to the context of their land, illustrates their ingenious capacity to model their hostile surroundings and to leave marks of their cultures all over prehistory and history.

Social organizations in those arid areas are closely linked to modes of exploitation and valuation of resources (water and land). However, human productions in those areas are doubly menaced; on one side by the action of humans who exploit resources for their immediate needs, and on the other side, by climate adverse effects during long periods of drought. It means that climate change and violent meteorological phenomenon worsen circumstances. That leads to environmental degradation and biodiversity reduction; alarming deterioration of vital conditions; and intensification of poverty, both in rural and urban areas; particularly among women and young. Consequently, there are non durable (viable) agricultural practices, overexploitation, overgrazing, excessive and illegal forestry exploitation; destruction of forests and bushes by non-controlled fires, pillages and conflicts with weapons; reduction of vegetation, due to the scarcity of rain; of water in general and menaces of heaps of sands.

Agroforestry systems are more complex than the agricultural systems. The long-term nature of trials involving woody species and the varying objectives of agroforestry trials demand that adequate caution be exercised in their design. Several characteristics of the trees like slow growth, long-term effects on their surroundings, long life, age of trees, the area over which the influence of trees extend, etc. complicate the issue of designing experiments for these systems. Agroforestry experiments are often established on marginal sites which include sloping lands, and sites with infertile and degraded soils. It is thus difficult to find homogeneous sites of such problem areas, especially sloping lands where plots along contour lines are long and linear. Germplasm of many agroforestry tree species are usually collected from different origins which lack uniformity. Therefore, experimental materials in an agroforestry experiment may not be of uniform quality.

There are several features of agroforestry systems that require some modification of the methods usually used in agricultural experiments. Important issues related to agroforestry experiments include

Agroforestry systems are more complex than the agricultural systems. The long-term nature of trials involving woody species and the varying objectives of agroforestry trials demand that adequate caution be exercised in their design. Several characteristics of the trees like slow growth, long term effects on their surroundings, long life, age of trees, the area over which the influence of trees extend, etc. complicate the issue of designing experiments for these systems. Agroforestry experiments are often established on marginal sites which include sloping lands, and sites with infertile and degraded soils. It is thus difficult to find homogeneous sites of such problem areas, especially sloping lands where plots along contour lines are long and linear. Germplasm of many agroforestry tree species are usually collected from different origins which lack uniformity. Therefore, experimental materials in an agroforestry experiment may not be of uniform quality.

There are several features of agroforestry systems that require some modification of the methods usually used in agricultural experiments. Important issues related to agroforestry experiments include

Introduction

In almost all biological studies, it will be impossible to account for every individual in a population. Therefore, it is necessary to examine a sub-group of the total population and extrapolate from this to the whole population. The process by which the sub-group of the population is selected is sampling. Nearly, all statistical tests make a fundamental assumption that sampling of individual will be at random from all the individuals that could possibly be sampled. It is very important that timing is taken into account either by sampling strategy or by later analysis. Most population will be affected by season, time of day and local weather conditions.

What is considered here is the problem faced by an ecologist working in the field and trying to design a suitable sampling strategy. The use of the very powerful statistical technique; analysis of variance (ANOVA) is more common in the situation of a controlled experiment, where, we are analyzing the effects of different levels of a treatment (e.g. feed, fertilizer, temperature etc.) on some measured aspect of population, Then, to get a true estimate of the effect of the treatment, experimental design will be of paramount importance.

Greenhouse refers to a structure which provide relatively better environment for plant growth. The goal is to create congenial temperature and relative humidity in desired range. The greenhouse covered with polythene sheet, also called as polyhouse, has polythene sheet (UV stabilized 200 micron LDPE sheet) as covering over a relatively rigid frame (made of GI pipes, angle iron, boomboo or wooden) which entraps the solar energy to increase the temperature and provide light for plant propagation. A normal greenhouse has four basic components: 1) frame made from rigid material like GI pipes, wood or bamboo; 2) glazing material, which is transparent to provide enough light for plant propagation; 3) climate control system, which may be natural ventilation or forced ventilation using fans with or without cooling pads, shading nets, pigment painting, etc. and 4) plant growing medium (soil or artificial media like cocopeats) with needful arrangement for supplying inputs (water, fertilizers, pesticides, etc.). The design of greenhouse involves structural design of frame with enough climate control mechanism. It mainly depends on shape, size, material of frame, local climatic conditions, wind pressure, and desired height from crop production point of view. Fabrication of greenhouse should be such that it provides enough structural stability with wind pressure and other factors, perfect joints, anchoring of polythene, and minimum hindrances in crop production practices.

Design and Construction of a greenhouse involves five distinctly different aspects viz. (a) Basic form or type, (b) structure/designs, (c) covering materials and its fixing, (d) foundation and constructional detail, and (e) crop-support, irrigation and drainage planning.

All the above aspects are interlinked. To have a clear idea, these individual aspects are discussed separately.

4.1. Basic Forms of Greenhouse

Before considering anything about construction, one should finalize the form of construction. There are different forms of greenhouses for different climatic and crop situations. These types of structures are planned according to the requirement of farmer/promoter and obviously according to the purpose. Now we will describe, in brief, some of the important form or type of greenhouses.

4.1.1. Greenhouse covered with transparent and impervious material

These structures are covered with water/rain impermeable transparent materials which allow necessary solar radiation for optimal growth of plants. Simultaneously it protects crops from temperature-fluctuation, rain, wind, and creates a favourable situation in respect of CO₂ and humidity. This covering is also used to prevent the re-radiation of heat energy and conserve the heat generated in daytime to raise night temperature inside.

Two principal hatchery systems are widely adopted in aquaculture: the large-tank hatchery system and the small-tank hatchery system. Recently, hybrid systems have emerged that integrate advantageous features from both approaches, particularly addressing constraints related to spawner availability.
KEY DETERMINANTS IN HATCHERY DESIGN
Three major factors govern the design of an aquaculture hatchery:
1. Target Species: The specific biological and ecological requirements of the species to be cultured are critical. Hatchery infrastructure must accommodate these needs, and as such, a clearly defined target species is essential before initiating the design process.
2. Production Target: The hatchery’s output goal is determined by market demand and available financial investment. For species such as Penaeus monodon, where fry production is reliant on wild spawner collection, output is naturally capped by spawner availability. In contrast, species like P. japonicus and white shrimp, which have abundant spawner supply, allow for scalable production targets.
3. Financial Inputs: Investment capacity influences not only the scale of operations but also the complexity and automation of the hatchery. In Japan, for example, large-scale hatcheries culturing P. japonicus feature tanks with capacities reaching up to 2,500 cubic meters. In Southeast Asia, where P. monodon is the primary hatchery species and wild spawner availability is limited, smaller tank capacities are the norm.

Introduction

Agriculture is the most important sector of Indian Economy. The agriculture sector accounts for 18 per cent of India’s gross domestic product (GDP) and provides employment to 50 per cent of the countries workforce. India has emerged as the second-largest producer of fruits and vegetables in the world. Formerly agriculture was more dependent on nature and all the operations were carried out manually, however new technologies have been developed to increase the production and productivity of crops (Rangbhal, 2018).

Introduction

Technologies and tools that have developed in the recent information technology revolution can play a very vital role in overcoming most of the present problems related to agriculture and rural development. In order to achieve the goal of an economically sound and stable society through environmentally friendly systems of agricultural production, it is imperative to have a comprehensive data storage system. This will not only help in providing systematic and periodic information to the planners, decision-makers and developmental agencies, but also help to manage our limited natural resources efficiently. The development of a data warehouse is one of the recent tools in the field of information technology that can fulfill the demands of the information that is required in the field of agriculture research, management and education

1. Context

Women play a critical role in agriculture, and agriculture continues to remain the major livelihood strategy for women as well as millions of small, marginal and poor farming households in India. Despite this, farm women lack access to extension services as extension programmes rarely identify women as an integral client. Farm women and men have differential needs for knowledge, information, technology and skills as often they are involved in different activities spread over time and cropping seasons. Besides these, men and women farmers have differential access to assets, information, markets, credits, and other services that are necessary for using new knowledge, technologies and skills. Ignoring women while delivering services and technologies creates a gap as many of the agricultural operations are performed by women only.

It is estimated that if women had the same access to productive resources as men, they could increase yields on their farms by 20-30 per cent (FAO, 2011). Yields on plots managed by women are lower than those managed by men, as they do not have the same access to inputs. If they did, their yields would go up, they would produce more, and overall agricultural production would increase. It isn’t merely about enhancing productivity but also about being fair and equitable. Women are a significant part of the agricultural workforce and they deserve to be consulted prior to formulation of agricultural development plans and policies. SDG 5 on Gender Equality “Achieve gender equality and empower all women and girls” is closely aligned to this aspect. Moreover, enhanced access to services can help women grow more food, have more say in the family, and could potentially lead to more income and food in women’s hands-leading to better food security and nutrition for the entire family as they are the major caregivers in the family.