Protection from Punishment Essay -- Government, Separation of Powers,

During the early stages of the creation of a government, it is common to witness a heavy debate over ways to both restrict the power of the government from becoming a tyranny and protect the rights of individual citizens. Founders often realize that individual citizens, if not protected somehow, would be powerless to prevent against such a government if it became corrupt. Therefore, in the creation of the American and British governments, those worried about these possibilities suggested separations of power and individual rights to be included in the documents that form the government. This debate was extremely controversial in the formation of the American government, and created a rift that, if not resolved, could have torn apart the country. Understanding this possibility, the Federalists of America agreed to hear out the proposals of the Anti-Federalists during the ratification debates of 1789 through 1791. This Bill of Rights emphasized individual rights that would protect powe rless citizens from possible tyranny of the federal government, both physical and abstract. One of the amendments proposed by James Madison, and subsequently ratified, was that â€Å"Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.† This amendment was eventually grouped into the ten amendments of the Bill of Rights, and is now known simply as the Eighth Amendment. Though this seems to be a rather straightforward law, below the surface one can see the history of struggle it was derived from, the fight that ensued over its incorporation, and how even the terms it uses have greatly affected its interpretation since December 15, 1791. As America was created almost as a child of the British Empire,... ...† (Levy 238). This is very symbolic of the American nature of law in general, as the American ideal is to create a country of responsible citizens, not just to lock them away. The Eighth Amendment’s history, through the tortures of scores of people to the debates over its inception, is filled with examples that define the history of American government. Though not the most discussed amendment during the revolutionary stage, the Eighth Amendment is quite possibly the most controversial article of the Bill of Rights in today’s society, as the question of punishment, specifically the death penalty, is constantly under debate. It is fascinating to study how, even at a time of such confusion and chaos, founders such as Madison and Henry were able to create an amendment that would retain the rights of citizens in a constantly progressing society for centuries to come.

Theory of Mercantilism

Theory of Mercantilism Most of the European economists who wrote between 1500 and 1750 are today generally considered mercantilists; this term was initially used solely by critics, such as Mirabeau and Smith, but was quickly adopted by historians. Originally the standard English term was â€Å"mercantile system†. The word â€Å"mercantilism† was introduced into English from German in the early 19th century. The bulk of what is commonly called â€Å"mercantilist literature† appeared in the 1620s in Great Britain. 6] Smith saw English merchant Thomas Mun (1571–1641) as a major creator of the mercantile system, especially in his posthumously published Treasure by Foreign Trade (1664), which Smith considered the archetype or manifesto of the movement. [7] Perhaps the last major mercantilist work was James Steuart’s Principles of Political Economy published in 1767. [8] â€Å"Mercantilist literature† also extended beyond England. For example, Ital y, France, and Spain produced noted writers of mercantilist themes including Italy's Giovanni Botero (1544–1617) and Antonio Serra (1580-? ; France's, Jean Bodin, Colbert and other physiocrats. Themes also existed in writers from the German historical school from List, as well as followers of the â€Å"American system† and British â€Å"free-trade imperialism,† thus stretching the system into the 19th century. However, many British writers, including Mun and Misselden, were merchants, while many of the writers from other countries were public officials. Beyond mercantilism as a way of understanding the wealth and power of nations, Mun and Misselden are noted for their viewpoints on a wide range of economic matters. [9] Merchants in VeniceThe Austrian lawyer and scholar Philipp Wilhelm von Hornick, in his Austria Over All, If She Only Will of 1684, detailed a nine-point program of what he deemed effective national economy, which sums up the tenets of mercantilism comprehensively:[10] That every inch of a country's soil be utilized for agriculture, mining or manufacturing. That all raw materials found in a country be used in domestic manufacture, since finished goods have a higher value than raw materials. That a large, working population be encouraged. That all export of gold and silver be prohibited and all domestic money be kept in circulation.That all imports of foreign goods be discouraged as much as possible. That where certain imports are indispensable they be obtained at first hand, in exchange for other domestic goods instead of gold and silver. That as much as possible, imports be confined to raw materials that can be finished [in the home country]. That opportunities be constantly sought for selling a country's surplus manufactures to foreigners, so far as necessary, for gold and silver. That no importation be allowed if such goods are sufficiently and suitably supplied at home.Other than Von Hornick, there were no mercantilist wr iters presenting an overarching scheme for the ideal economy, as Adam Smith would later do for classical economics. Rather, each mercantilist writer tended to focus on a single area of the economy. [11] Only later did non-mercantilist scholars integrate these â€Å"diverse† ideas into what they called mercantilism. Some scholars thus reject the idea of mercantilism completely, arguing that it gives â€Å"a false unity to disparate events†. Smith saw the mercantile system as an enormous conspiracy by manufacturers and merchants against consumers, a view that has led some authors, especially Robert E.Ekelund and Robert D. Tollison to call mercantilism â€Å"a rent-seeking society†. To a certain extent, mercantilist doctrine itself made a general theory of economics impossible. Mercantilists viewed the economic system as a zero-sum game, in which any gain by one party required a loss by another. [12] Thus, any system of policies that benefited one group would by de finition harm the other, and there was no possibility of economics being used to maximize the â€Å"commonwealth†, or common good. [13] Mercantilists' writings were also generally created to rationalize particular practices rather than as investigations into the best policies. 14] Mercantilist domestic policy was more fragmented than its trade policy. While Adam Smith portrayed mercantilism as supportive of strict controls over the economy, many mercantilists disagreed. The early modern era was one of letters patent and government-imposed monopolies; some mercantilists supported these, but others acknowledged the corruption and inefficiency of such systems. Many mercantilists also realized that the inevitable results of quotas and price ceilings were black markets.One notion mercantilists widely agreed upon was the need for economic oppression of the working population; laborers and farmers were to live at the â€Å"margins of subsistence†. The goal was to maximize pro duction, with no concern for consumption. Extra money, free time, or education for the â€Å"lower classes† was seen to inevitably lead to vice and laziness, and would result in harm to the economy. [15] Infinite growth The mercantilists saw a large population as a form of wealth which made possible the development of bigger markets and armies. The opposing doctrine of physiocracy predicted that mankind would outgrow its resources.Origins Scholars debate over why mercantilism dominated economic ideology for 250 years. [16] One group, represented by Jacob Viner, argues that mercantilism was simply a straightforward, common-sense system whose logical fallacies could not be discovered by the people of the time, as they simply lacked the required analytical tools. The second school, supported by scholars such as Robert B. Ekelund, contends that mercantilism was not a mistake, but rather the best possible system for those who developed it. This school argues that mercantilist poli cies were developed and enforced by rent-seeking merchants and governments.Merchants benefited greatly from the enforced monopolies, bans on foreign competition, and poverty of the workers. Governments benefited from the high tariffs and payments from the merchants. Whereas later economic ideas were often developed by academics and philosophers, almost all mercantilist writers were merchants or government officials. [17] Monetarism offers a third explanation for mercantilism. European trade exported bullion to pay for goods from Asia, thus reducing the money supply and putting downward pressure on prices and economic activity.The evidence for this hypothesis is the lack of inflation in the English economy until the Revolutionary and Napoleonic wars when paper money was extensively used. A fourth explanation lies in the increasing professionalisation and technification of the wars of the era, which turned the maintenance of adequate reserve funds (in the prospect of war) into a more and more expensive and eventually competitive business. Mercantilism developed at a time when the European economy was in transition. Isolated feudal estates were being replaced by centralized nation-states as the focus of power.Technological changes in shipping and the growth of urban centres led to a rapid increase in international trade. [18] Mercantilism focused on how this trade could best aid the states. Another important change was the introduction of double-entry bookkeeping and modern accounting. This accounting made extremely clear the inflow and outflow of trade, contributing to the close scrutiny given to the balance of trade. [19] Of course, the impact of the discovery of America cannot be ignored. New markets and new mines propelled foreign trade to previously inconceivable heights.The latter led to â€Å"the great upward movement in prices† and an increase in â€Å"the volume of merchant activity itself. †[20] Prior to mercantilism, the most important ec onomic work done in Europe was by the medieval scholastic theorists. The goal of these thinkers was to find an economic system that was compatible with Christian doctrines of piety and justice. They focused mainly on microeconomics and local exchanges between individuals. Mercantilism was closely aligned with the other theories and ideas that were replacing the medieval worldview.This period saw the adoption of the very Machiavellian realpolitik and the primacy of the raison d'etat in international relations. The mercantilist idea that all trade was a zero sum game, in which each side was trying to best the other in a ruthless competition, was integrated into the works of Thomas Hobbes. The dark view of human nature also fit well with the Puritan view of the world, and some of the most stridently mercantilist legislation, such as the Navigation Acts, were enacted by the government of Oliver Cromwell. [21] PoliciesFrench finance minister and mercantilist Jean-Baptiste Colbert served for over 20 years. Mercantilist ideas were the dominant economic ideology of all of Europe in the early modern period, and most states embraced it to a certain degree. Mercantilism was centred in England and France, and it was in these states that mercantilist polices were most often enacted. France Mercantilism arose in France in the early 16th century, soon after the monarchy had become the dominant force in French politics. In 1539, an important decree banned the importation of woolen goods from Spain and some parts of Flanders.The next year, a number of restrictions were imposed on the export of bullion. [22] Over the rest of the sixteenth century further protectionist measures were introduced. The height of French mercantilism is closely associated with Jean-Baptiste Colbert, finance minister for 22 years in the 17th century, to the extent that French mercantilism is sometimes called Colbertism. Under Colbert, the French government became deeply involved in the economy in order to increase exports. Protectionist policies were enacted that limited imports and favored exports.Industries were organized into guilds and monopolies, and production was regulated by the state through a series of over a thousand directives outlining how different products should be produced. [23] To encourage industry, foreign artisans and craftsmen were imported. Colbert also worked to decrease internal barriers to trade, reducing internal tariffs and building an extensive network of roads and canals. Colbert's policies were quite successful, and France's industrial output and economy grew considerably during this period, as France became the dominant European power.He was less successful in turning France into a major trading power, and Britain and the Netherlands remained supreme in this field. [23] Great Britain In England, mercantilism reached its peak during the 1340-1789 Long Parliament government (1640–1660). Mercantilist policies were also embraced throughout much of the Tudor and Stuart periods, with Robert Walpole being another major proponent. In Britain, government control over the domestic economy was far less extensive than on the Continent, limited by common law and the steadily increasing power of Parliament. 24] Government-controlled monopolies were common, especially before the English Civil War, but were often controversial. [25] The Anglo-Dutch Wars were fought between the English and the Dutch for control over the seas and trade routes. With respect to its colonies, British mercantilism meant that the government and the merchants became partners with the goal of increasing political power and private wealth, to the exclusion of other empires. The government protected its merchants—and kept others out—by trade barriers, regulations, and subsidies to domestic industries in order to maximize exports from and minimize imports to the realm.The government had to fight smuggling—which became a favorite American tech nique in the 18th century to circumvent the restrictions on trading with the French, Spanish or Dutch. The goal of mercantilism was to run trade surpluses, so that gold and silver would pour into London. The government took its share through duties and taxes, with the remainder going to merchants in Britain. The government spent much of its revenue on a superb Royal Navy, which not only protected the British colonies but threatened the colonies of the other empires, and sometimes seized them. Thus the British Navy captured New Amsterdam (New York) in 1664.The colonies were captive markets for British industry, and the goal was to enrich the mother country. [26] British mercantilist writers were themselves divided on whether domestic controls were necessary. British mercantilism thus mainly took the form of efforts to control trade. A wide array of regulations was put in place to encourage exports and discourage imports. Tariffs were placed on imports and bounties given for exports, and the export of some raw materials was banned completely. The Navigation Acts expelled foreign merchants from England's domestic trade.The nation aggressively sought colonies and once under British control, regulations were imposed that allowed the colony to only produce raw materials and to only trade with Britain. This led to friction with the inhabitants of these colonies, and mercantilist policies (such as forbidding trade with other empires and controls over smuggling) were a major irritant leading to the American Revolution. Over all, however, mercantilist policies had a positive impact on Britain helping turn it into the world's dominant trader, and an international superpower[citation needed].One domestic policy that had a lasting impact was the conversion of â€Å"waste lands† to agricultural use. Mercantilists felt that to maximize a nation's power all land and resources had to be used to their utmost, and this era thus saw projects like the draining of The Fens. [27] Mercantilism helped create trade patterns such as the triangular trade in the North Atlantic, in which raw materials were imported to the metropolis and then processed and redistributed to other colonies. Other countries The other nations of Europe also embraced mercantilism to varying degrees.The Netherlands, which had become the financial centre of Europe by being its most efficient trader, had little interest in seeing trade restricted and adopted few mercantilist policies. Mercantilism became prominent in Central Europe and Scandinavia after the Thirty Years' War (1618–1648), with Christina of Sweden, Jacob Kettler of Courland, Christian IV of Denmark being notable proponents. The Habsburg Holy Roman Emperors had long been interested in mercantilist policies, but the vast and decentralized nature of their empire made implementing such notions difficult.Some constituent states of the empire did embrace Mercantilism, most notably Prussia, which under Frederick the Grea t had perhaps the most rigidly controlled economy in Europe. During the economic collapse of the seventeenth century Spain had little coherent economic policy, but French mercantilist policies were imported by Philip V with some success. Russia under Peter I (Peter the Great) attempted to pursue mercantilism, but had little success because of Russia's lack of a large merchant class or an industrial base.Wars and imperialism Mercantilism was economic warfare and was well suited to an era of military warfare. [28] Since the level of world trade was viewed as fixed, it followed that the only way to increase a nation's trade was to take it from another. A number of wars, most notably the Anglo-Dutch Wars and the Franco-Dutch Wars, can be linked directly to mercantilist theories. Most wars had other causes but they reinforced mercantilism by clearly defining the enemy, and justified damage to the enemy's economy.Mercantilism fueled the imperialism of this era, as many nations expended si gnificant effort to build new colonies that would be sources of gold (as in Mexico) or sugar (as in the West Indies), as well as becoming exclusive markets. European power spread around the globe, often under the aegis of companies with government-guaranteed monopolies in certain defined geographical regions, such as the Dutch East India Company or the British Hudson's Bay Company (operating in present-day Canada).

Advances in Modern Irrigation Systems Essay

ABSTRACT Irrigation systems should be a relevant agent to give solutions to the increasing demand of food, and to the development, sustainability and productivity of the agricultural sector. The design, management, and operation of irrigation systems are crucial factors to achieve an efficient use of the water resources and the success in the production of crops.The aim of this paper is to analyze the advances made in irrigation systems as well as identify the principal criteria and processes that allow improving the design and management of the irrigation systems,based on the basic concept that they facilitate to develop agriculture more efficiently and sustainable. The advances and management of irrigation systems at farm level is a factor of the first importance for the rational use of water, economic development of the agriculture and its environmental sustainability. Key words: Irrigation, Design, Water Management, Operation Systems INTRODUCTION Water required by crops is supplied by nature in theform of precipitation, but when it becomes scarce or its distribution does not coincide with demand peaks, it is then necessary to supply it artificially, by irrigation. Several irrigation methods are available, and the selection of one depends on factors such as water availability, crop, soil characteristics, land topography, and associated cost. In the near future, irrigated agriculture will need to produce two-thirds of the increase in food products required by a larger population (English et al., 2002). The growing dependence on irrigated agriculture coincides with an accelerated competition for water and increased awareness of unintended negative consequences of poor design and management (Cai et al., 2003) Optimum management of available water resources at farm level is needed because of increasing demands, limited resources, water table variation in space and time, and soil contamination (Kumar and Singh, 2003). Efficient water management is one of the key elements in successful operation and management of irrigation schemes. Irrigation technology has made significant advances in recent years. Criteria and procedures have been developed to improve and rationalize practices to apply water, through soil leveling, irrigation system design, discharge regulations, adduction structures, and control equipment. However, in many regions these advances are not yet available at the farm stage. Irrigation systems are selected, designed and operated to supply the irrigation requirements of each crop on the farm while controlling deep percolation, runoff, evaporation, and operational losses, to establish a sustainable production process. Playà ¡n and Mateos (2006) mentioned that modernized irrigation systems at farm level implies selecting the appropriate irrigation system and strategy according to the water availability, the characteristics of climate, soil and crop, the economic and social circumstance s, and the constraints of the distribution system. Efficient irrigation equipment generally comes in two broad categories—drip and sprinkler irrigation. Both of these areas have several sub-types of equipment in them. Within drip irrigation are surface drip equipment, subsurface drip equipment and micro sprays/sprinklers. This category of drip irrigation and particularly subsurface drip irrigation (SDI) is one of the most exciting and newest technologies in irrigation. Drip irrigation has attracted tremendous interest by academics, who measure the performance of drip systems and promote drip as a water savings technology. Sprinkler equipment can also be broken down into several subcategories including wheel lines, solid set and hand move pipe, traveling guns, and mechanical move irrigation (MMI) systems, which include center pivots and linear move equipment. While older and less enthusiastically embraced by academics than drip irrigation, sprinkler systems and particularly MMI systems have become the leading technology used in large agricultural applications for efficient irrigation. With the advent of Low Energy Precision Application (LEPA) configurations in the 1980’s, MMI systems achieve irrigation efficiencies rivaling subsurface drip. Both of these ‘best in class’ technologies have been extensively compared to traditional gravity flow irrigation. Both systems can demonstrate significantly better overall performance than traditional irrigation methods. Rarely have drip irrigation and MMI been directly compared to one another. The balance of this paper will draw comparisons between these two types of irrigation systems, and explore how appropriate each technology is for various types of farming operations. IRRIGATION SYSTEM PERFORMANCE Up to this point, our discussion on advances in irrigation has focused on water savings. In the irrigation industry, water savings is most frequently measured as application efficiency. Application efficiency is the fraction of water stored in the soil and available for use by the crop divided by the total water applied. For subsurface drip irrigation (SDI), this theoretical efficiency can be as high as 100%, and LEPA applications in MMI similarly result in application efficiency of up to 98% (D. Rogers, 2012). While application efficiency is a good starting point in understanding irrigation performance, efficiency measurements under ideal conditions on a test plot hardly tell the whole story about irrigation performance. In general, we can analyze irrigation performance in five categories as shown below WATER EFFICIENCY Researchers generally give the edge to subsurface drip irrigation SDI when they evaluate water efficiency. According to the IrrigationAssociation, subsurfacedrip irrigation (SDI) installations, if properly managed, can achieve 95% water efficiency (James Hardie, 2011). This high level of water efficiency isapproximately the same as what a LEPA center pivot or linear system achieves, at 90-95%, and definitely better than the 75-85% efficiency of center pivot with the obsolete water application method of impact sprinklers mounted to the top of the MMI system’s pipe. Gravity flow installations are typically around 40%-50% efficient. For the purpose of a farmer’s consideration, LEPA and SDI systems can be thought of as having equivalent potential efficiency. Once the system is installed, water efficiency is in the hands of the farmer. While data on this topic is difficult to find, it seems that farmers habitually over-apply water to their fields with all types of irrigation equipment including gravity flow. Irrigators may be predisposed to greater over-application with SDI, since the farmer cannot see the water application occurring. Both systems will benefit from more sophisticated information on evapotranspiration and plant health to allow more precise application of water and reduce over-application. SDI systems typically require periodic cleaning and flushing to prevent root ingression and plugging. Such flushing is not a requirement with MMI equipment. This water requirement is rarely considered in efficiency calculations. CROP YIELD DRIVER In most cases, the contribution that an irrigation system can make to reaching optimal crop yields is by delivering water to plants when they need it and by applying water uniformly over the area of the field. However, when the available water supply is insufficient to fully meet the water needs of a crop, then the highest crop yields will be achieved by the irrigation system with the highest application efficiency. Uniform water application by MMI systems is determined by sprinkler package design and by the rate at which the equipment moves across the field. Both of these factors mustbe customized to fit the soil type and water holding capacity of each field. MMI experts today have a very good understanding of the relationship between soil type, water holding capacity, equipment speed, and sprinkler package design, and they have even developed several computer programs to generate highly uniform patterns of water distribution for low pressure and LEPA systems. Changes in the elevation of terrain can beaccommodated by the use of pressure regulators. Uniformity of MMI systems is fairly constant over time. Variations among individual nozzles is significantly reduced by the movement of the equipment and by the overlap between the wetted diameters of soil irrigated by each individual sprinkler head. Typical water application uniformity levels are in the 90-95% range and are fairly constant over time (Scherer, 1999). In applications with high levels of abrasives present in the water, sprinkler packages must be replaced and redesigned every few years to maintain watering uniformity. Drip systems can also be designed to have high levels of uniformity. A typical design targets uniformity levels in the 85% range. SDI design is not as standardized as MMI system design is, and consequently the water application of any drip system is highly dependent on the skill and knowledge the technician who designed it. Unlike MMI systems, drip system uniformity c an change substantially over time if proper maintenance is not performed to the drip installation. This is particularly difficult for subsurface systems, whose emitters are more likely to suck in soil which cannot then be easily removed by hand since the emitters are buried underground. According to a South African study published in 2001, field examinations of drip systems show that water application uniformity deteriorates significantly over time.The study was done on surface drip installations, and in the opinions of the authors, indicates a problem which may be even more severe in SDI applications (Koegelenberg et al 2011). System availability and controllability is generally good with both MMI and SDI systems, since both offer the ability to irrigate at least once every 24 hours. The exception to this can be with towable pivots, where use of the equipment on multiple fields may limit its availability. Both systems support the use of sophisticated automatic controls and remote control and monitoring. Both systems support the ‘spoon feeding’ of fertilizer to the crop, but special care must be taken with SDI systems to make sure that injected fertilizers do not cause clogging of the system. For SDI systems, soil salinization is also a significant problem in areas where salts are present in irrigation water. As salts build up in soil, crop yields decrease. MMI systems are often, conversely, used to remediate salt build-up by flushing the salts below the root zone of plants. Based on a review of available literature, itappears that in non-water limited applications, SDI and MMI systems produce equivalent yields, although the center pivot will use slightly more water in those comparisons due to losses fromsurface evaporation. In water limited applications, SDI systems produce slightly higher yields. Over time, SDI system maintenance is of great importance. A lapse in system maintenance can result in a significant and permanent degradation of watering uniformity, which in turn causes permanently higher water consumption and lower crop yields. COST DRIVERS A lot of conflicting information exists concerning the costs of both SDI and MMI systems. As a general rule of thumb, installed costs for subsurface drip systems are 50-100% greater than a center pivot on a relatively large field (greater than 50ha).(O’Brien et al 1998). Cost depends on a number of factors including: availability of proper power, filtration type used in the drip system, the value of installation labor, towable vs. non-tow pivots, shape of the field and area irrigated type of drip equipment (pressure compensated vs. non-pressure compensated) and the use of linear move equipment, or corner arm extensions on a center pivot. Also important to the long-term cost is the expected life. Center pivots have an average life expectancy of 25 years with minimal maintenance expenses, typically less than 1% per year of the original price. In a few installations where the source water is corrosive to galvanize steel, it is important for the buyer to move to corrosion resistan t products such as aluminum, stainless steel, or polyethylene lined systems. Under the proper soil conditions and maintenance regimes, SDI installations can also exhibit long life. Some research installations have surpassed 20 years of usage with still functioning systems. Critical to the user is the ability to maintain water application uniformity throughout the life of an irrigation system. In most commercial installations, drip systems performance degrades with time due to plugging, root intrusion, and pest damage. Diagnosis and repair of SDI system problems can be expensive and challenging to perform. Typical maintenance costs range from 3% to 10% per year of the original system cost. Another advantage of MMI technology is its portability. It is not uncommon for a center pivot to be moved several times during its expected service life. Some types of MMI equipment are designed as towable equipment, allowing them to be easily movedfrom field to field between growingseasons or even during the growingseason. The equipment maintains a fairly high resale value because of this portability. SDI systems, with the exception of some filtration and control elements, are generally not salvageable or resell able at all. In addition to maintenance and repair costs, the other significant system operating cost is energy used to pump water and field labor. Energy costs are related to the volume of water pumped and the pressure required. Research shows that these two costs are nearly equal for SDI and MMI systems. Center pivot and linear systems at research plots typically pump slightly more volume of water then SDI systems, but SDI pump outlet pressures are typically higher (3 bar vs. 1.5-2 bar). Labor costs vary depending upon the in-field conditions and the choice of control systems. One 1990 article shows pivots to require 3 hours per hectare, while drip requires 10 hours per hectare.(Kruse et al, 1990). Even in trouble-free installations of equal control sophistication, SDI seems to require more labor because of its regularly required maintenance cycle. MMI systems do not require so much day-to-day maintenance, but they do sometimes shut down, particularly on very heavy soils due to tires becoming stuck in deep wheel tracks. CROP SPECIFIC CONSIDERATIONS Different crop specific characteristics favor one system type over another. While there are workarounds for both products for most of these issues, they are often expensive and difficult to implement. Drip systems or micro-irrigation are often preferred by growers when crop height may be an issue for mechanical systems as over cashew nut trees, or with planting patterns not conducive to above ground mobile irrigation equipment as with vineyards. Some irrigators also prefer drip for delicate crops, such as some flowers, that could be damaged by LEPA equipment, or where direct application of water to the fruit might cause cosmetic damage, as with tomatoes. Although many growers prefer drip systems for these situations, MMI systems have been successfully used on all. MMI systems are preferred where surface water application isrequired to germinate seed as with carrots and onions, particularly in sandy soils. MMI systems also have an advantage in applying foliar herbicides and pesticides, and can be used for crop coolingin temperature sensitive crops such as corn. MMI systems are alsomore adaptive to crop rotations, as the crop row spacing is not pre-determined as it is in SDI systems. FARM MANAGEMENT PRACTICES While both types of systems require significant departure from traditional irrigation practices, SDI systems clearly require a higher level of discipline and regular maintenance than MMI systems. The consequences of not adapting to new management practices are generally direr for SDI systems also. SDI farms must commit to the regular cleaning and flushing procedures described by the system designer and the equipment manufacturers. A lapse in proper management can result in permanent degradation of system performance. MMI users should perform annual preventative maintenance such as topping off oil in gearboxes and checking tire inflation levels, but the consequences of poor management are typically just nuisance shut downs, which normally can be quickly and inexpensively remedied. A special problem that faces owners of MMI equipment in some third world countries is theft, particularly theft of motors, controls and copper wire. To combat this problem, a number of adaptations have been made to reduce the risk of theft on the system. Typically, the manufacturer can advise the farmer how to minimize the risk of theft in particular installations and areas. MMI systems are less flexible when it comes to field configuration and water infrastructure. Farmland laid out in 2 hectare plots with canals serving the individual fields, for example, are difficult to adapt to MMI systems. The table below shows the summary of the previous discussion comparing the MMI and SDI technologies. Analysis of SDI and MMI System Performance| Water Efficiency * SDI has slightly higher efficiency than LEPA (95% vs. 90-95%) in research installation. * No known studies yet compare actual on-farm efficiency| Crop Yields * SDI performs better in research tests when water availability is the limiting factor, otherwise yields are equivalent between the two systems. * Uniformity of SDI systems appears to degrade over time, favoring MMI. * Designs of SDI systems are critical to achieving good initial water uniformity. * Where salinity is a problem, MMI systems have a clear edge.| Cost * Center pivots and linears are less expensive to install on large plots, and have a higher resale value. * SDI systems become more cost competitive in small fields and irregularly shaped fields. * MMI systems have long lives (25 years on average). SDI can have a life of 10-15 years if proper maintenance is performed. * Ongoing maintenance costs of SDI are 3-5 times higher than MMI. * Operating costs for energy are similar between the two technologies, but MMI systems typically require much less labor.| Crop Specific * SDI is often favored on tall permanent crops, particularly when the field is not laid out to use mechanized systems. * MMI systems are preferred in sandy soils where surface application is necessary for germination. * Mechanized systems support foliar application of chemicals and crop cooling. * Mechanized systems are preferred where there are frequent crop rotations.| Farm Management * SDI systems are less adaptive and forgiving to poor management practices. * Theft is an issue for mechanized systems in some third world markets. * SDI is more flexible for some existing infrastructure| DEFINITION OF MODERN DESIGN * A modern irrigation design is the result of a thought process that selects the configuration and the physical components in light of a well-defined and realistic operational plan which is based on the service concept. * Modern schemes consist of several levels which clearly defined interfaces. * Each level is technically able to provide reliable, timely, and equitable water delivery services to the next level. That is, each has the proper types, numbers, and configuration of gates, turnouts, measurement devices, communications systems and other means to control flow rates and water levels as desired. * Modern irrigation schemes are responsive to the needs of the end users. Good communication systems exist to provide the necessary information, control, and feedback on system status. * The hydraulic design is robust, in the sense that it will function well in spite of changing channel dimensions, siltation, and communication breakdowns. Automatic devices are used where appropriate to stabilize water levels in unsteady flow conditions. ADVANCES MADE IN IRRIGATION MICRO IRRIGATION During the last three decades, micro irrigation systems made major advances in technology development and the uptake of the technology increased from 3 Mha in 2000 to more than 6 Mha in 2006. Micro-irrigation is an irrigation method that applies water slowly to the roots of plants, by depositing the water either on the soil surface or directly to the root zone, through a network of valves, pipes, tubing, and emitters (see Figure below). Fig. 1: Components of a micro-irrigation system EARLY HISTORY OF MICRO-IRRIGATION Drip irrigation was used in ancient times by filling buried clay pots with water and allowing the water to gradually seep into the soil. Modern drip irrigation began its development in Germany in 1860 when researchers began experimenting with sub irrigation using clay pipe to create combination irrigation and drainage systems. In 1913, E.B. House at Colorado State University succeeded in applying water to the root zone of plants without raising the water table. Perforated pipe was introduced in Germany in the 1920s and in 1934; O.E. Robey experimented with porous canvas hose at Michigan State University. With the advent of modern plastics during and after World War II, major improvements in drip irrigation became possible. Plastic micro tubing and various types of emitters began to be used in the greenhouses of Europe and the United States. A new technology of drip irrigation was then introduced in Israel by Simcha Blass and his son Yeshayahu. Instead of releasing water through tiny holes, blocked easily by tiny particles, water was released through larger and longer passage ways by using friction to slow the water flow rate inside a plastic emitter. The first experimental system of this type was established in 1959 in Israel by Blass, where he developed and patented the first practical surface drip irrigation emitter. The Micro-sprayer concept was developed in South Africa to contain the dust on mine heaps. From here much more advanced developments took place to use it as a method to apply water to mainly agricultural crops. ADVANTAGES OF MICRO-IRRIGATION The advantages of drip irrigation are as follows: * Sophisticated technology * Maximum production per mega litre of water * Increased crop yields and profits * Improved quality of production * Less fertilizer and weed control costs * Environmentally responsible, with reduced leaching and run-off * Labour saving * Application of small amounts of water more frequent DISADVANTAGES OF MICRO-IRRIGATION The disadvantages of micro-irrigation are as follows: * Expensive * Need managerial skills * Waste: The plastic tubing and â€Å"tapes† generally last 3-8 seasons before being replaced * Clogging * Plant performance: Studies indicate that many plants grow better when leaves are wetted as well CENTER-PIVOT IRRIGATION The biggest single change since the first irrigation symposium is the amount of land irrigated with center-pivot and linear-move irrigation machines. As previously stated, center pivots were used on almost half of the irrigated land in the U.S. in 2008 (USDA-NASS, 2012). Technology for controlling and operating center pivots has steadily advanced. Kranz et al. (2012) describe how operators can now communicate with irrigation machines by cell phone, satellite radio, and internet-based systems. New sensors are being developed to collect soil or crop information that can be used for managing irrigation. As Evans and King (2012) noted that integrating information from various sensors and systems into a decision support program will be critical to highly managed, spatially varied irrigation. Technology has allowed irrigators to precisely control irrigation. However, technology to precisely apply irrigation water is wasted if the water does not infiltrate into soil where it was applied. King and Bjorneberg (2012) characterize the kinetic energy applied to the soil from common center-pivot sprinklers and relate this energy to runoff and soil erosion to improve center-pivot sprinkler selection. Finally, Martin et al. (2012) describe the wide variety of sprinkler packages available for mechanical-move irrigation machines and how those sprinkler packages are selected. Above Left: A Field VISION control panel operates one of his pivots Above Right: A computer screen display showing the exact position of the irrigation pivot, along with how much water is being sprayed on the crop A Zimmatic Pivot Irrigation System An Irrigation Field Covered by a Center Pivot Irrigation System A Center Pivot Irrigation System in Action CONCLUSION The success or failure of any irrigation system depends to a large extent on careful selection, thorough planning, accurate design and effective management. One thing we can be certain of, the demands of irrigated agriculture will certainly not diminish, they will indeed increase almost exponentially. Advanced surface irrigation will still dominate as the primary irrigation method, but with the current trends, the area under micro-irrigation will continue to expand. Both subsurface drip and mechanical move irrigation systems have a legitimate place in agricultural water conservation plans for the future. Both systems offer significant potential water application reduction, as well as yield improvements over traditionally managed irrigation fields. In general, mechanized systems are most suitable for: broad area crops in large fields, new land development, and sandy soils. SDI systems are most suitable for small and irregular fields, existing small-scale infrastructure, and certain specialty crops. These innovative technologies require significant investment. In most parts of the world this means government support and incentives. Mexico and Brazil are two leading countries in providing effective incentives to farmers to invest in modern efficient agricultural irrigation. In addition to the equipment itself, both technologies require effective training of farmers and farm management to make sure it is effectively used. Poor management can easily offset most of the water saving and yield gains made possible by the equipment. Employing the modern technology available for water-efficient irrigation is clearly a key to over coming the global challenges of water scarcity. Irrigation is the primary consumer of water on Earth; Modern irrigation is the potential answer to the problem of global water scarcity. REFERENCES English, M.J., K.H. Solomon, and G.J. Hoffman. 2002.A paradigm shift in irrigation management. J. Irrig. Drain. Eng. 128:267-277. Evans, R. G. and B. A. King. 2012. Site-specific sprinkler irrigation in a water-limited future. Trans. ASABE 55(2): 493-504. Cai, X., D.C. McKinney, and M.W. Rosegrant. 2003. Sustainability analysis for irrigation water management in the Aral Sea region. Agric. Syst. 76:1043-1066. James Hardie. 2011. Drip Irrigation for Landscaping: An Introductory Guide,26, in Irrigation Association, â€Å"Agricultural Hardware,† Agricultural School of Irrigation, 17 King, B. A. and D. L. Bjornberg.2012. Droplet kinetic energy of moving spray-plate center-pivot irrigation sprinklers. Trans. ASABE 55(2): 505-512. Koegelenberg, F. and R. Reinders. 2011. Performance of Drip Irrigation Systems under Field Conditions (South Africa: Agricultural Research Center-Institute for Agricultural Engineering). Kranz, W. L., R. G. Evans, and F. R. Lamm. 2012. A review of center-p ivot irrigation control and automation technologies. Applied Eng. in Agric. 28(3): (in press) Kruse, A., B.A. Stewart, and R.N. Donald. 1990. Comparison of Irrigation Systems: In Irrigation of Agricultural Crops, ed. (Madison, WI: American Society of Agronomy, 1990), 475-505. Kumar, R. and J. Singh. 2003. Regional water management modeling for decision support in irrigated agriculture. J. Irrig. Drain. Eng. 129:432-439. Martin, D. L., W. R. Kranz, A. L. Thompson, and H. Liang. 2012. Selecting sprinkler packages for center pivots. Trans. ASABE 55(2): 513-523. O’Brien .E. 1998.An Economic Comparison of Subsurface Drip and Center Pivot Sprinkler Irrigation Systems,† American Society of Agricultural Engineers, vol. 14(4), (1998): 391-398. Playà ¡n, E., and L. Mateos. 2006. Modernization and optimization of irrigation systems to increase water productivity. Agric. Water Manage. 80:100-116. Rogers, D. 2012.LEPA Irrigation Management for Center Pivots. Irrigation Association Online; available from http://www.oznet.ksu.edu/library/ageng2/l907.pdf; Internet; accessed 15 October 2012 Scherer, 1999. Sprinkler Irrigation Systems (Ames, IA: Midwest Plan Service, Iowa State University, USDA-NASS. 2012. Farm and ranch irrigation survey. Washington, D.C.: USDA National Agricultural Statistics Service. Available at: www.agcensus.usda.gov. Accessed 11 October 2012