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Medium 9781780642703

3 Bioassays

Koul, O. CABI PDF

3

Bioassays

It is imperative to use standardized methods of testing for any bioactivity of a phytochemical, specifically when unknown new products are evaluated. According to Hurst

(1943) the fact that each component of a toxic compound may contribute towards gross toxicity restricts the usefulness of chemical assay as an index of toxicity. It is an invalid premise that the main purpose of any carrier solvent is to transmit the toxic compound to the insect in order to correlate chemical and biological tests, after which toxicant concentration is a limiting factor in biological activity. This assumption has been called a ‘standard’ protocol of insecticidal bioassays directed more towards arbitrary elimination of unknown variable factors than towards the fundamental causes of this variation. Bioassays against insects have been used for decades as a means of elucidating the activity of many chemical components.

The major goals achieved by using bioassay techniques are the determination of the roles of naturally occurring chemicals, the mechanism of resistance in crop plants and to find various insect control agents. As the aim of this book is to understand phytochemicals that are toxic to insects, it is imperative to know about certain fundamental requirements for such evaluations. The basic way of studying toxins is either to apply a product directly to the candidate insect body or

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Medium 9781780646862

Summary of Key Points

Finley, S. CABI PDF

Summary of Key Points

 Dry spells during the growing season, and not total rainfall deficits or droughts, are the principal cause of water deficit on most rainfed farms.

 The impact of dry spells on crop yields can be mitigated by adopting soil and water conservation practices, harvesting rainfall, applying supplemental irrigation, and/or practicing conservation agriculture.

 In many dryland areas, over half of the rain that falls is not captured by the soil but is lost as runoff, evaporation, deep percolation, and evaporation.

 The capacity of field soils to hold water is closely related to organic matter content and soil type.

 Soil organic matter content can be enhanced by providing soil cover, recycling plant residues into the soil, and planting several varieties of crop.

 Cover crops and green manures cover the soil while acting as natural fertilizer.

 Rainwater runoff can be beneficially harvested to provide additional water inputs.

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Medium 9781845939212

5 Is Agricultural Productivity Growth Slowing in Western Europe?

Fuglie, K.O., Ball, V.E., Wang, S.L. CABI PDF

5

Is Agricultural Productivity Growth

Slowing in Western Europe?

Sun Ling Wang, David Schimmelpfennig and Keith O. Fuglie

Economic Research Service, US Department of Agriculture, Washington, DC

5.1

Introduction

Agricultural production in Western Europe1 has been nearly stagnant for the past 25 years. According to the Food and Agriculture

Organization (FAO), agricultural output in

Western Europe in 2009 was only about 4% higher than it was in 1984. World Bank data report agricultural gross domestic product

(GDP) of the region grew by 26% (in constant US dollars) over the same period, but this was almost certainly a terms-of-trade or exchange rate effect, rather than a change in real production. The stagnation in real output could be due to rising costs of production (falling productivity) and/or fewer resources being employed in production.

The slow growth of agriculture in Western

Europe has meant that its share of global agricultural output has been falling steadily, from about 20% in the 1960s to less than

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Medium 9781786390325

17 Phytoremediation and the Key Role of PGPR

Singh, H.B.; Sarma, B.K.; Keswani, C. CABI PDF

17 

1

Phytoremediation and the Key Role of PGPR

Elisabetta Franchi1* and Gianniantonio Petruzzelli2

Eni S.p.A, Renewable Energy & Environmental R&D, S. Donato Milanese, Italy;

2

Institute of Ecosystem Study, National Council of Research, Pisa, Italy

17.1 Phytoremediation

The original concept of phytoremediation is derived from studies on plants which can uptake and tolerate extremely high levels of heavy metals. These plants were defined hyperaccumulators (Brooks et al., 1977) and these studies originated from an article

(Minguzzi and Vergnano, 1948), describing the ability of Alyssum bertolonii to accumulate very high amounts of nickel. Brooks

(1998) underlined the seminal importance of this article for the development of phytoremediation: ‘a small perennial shrub in

Tuscany, Italy, was destined to lead the way to a whole range of new technologies and discoveries’. Nowadays, phytoremediation identifies a series of plant-based technologies that can be applied to a wide range of organic and inorganic contaminants for remediating polluted soil, water and sediments, by exploiting the multiple properties of plants, which can be used in different specific processes.

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Medium 9781780647906

6: Choosing the Right Breed and Strain of Pig

Blair, R. CABI PDF

6

Choosing the Right Breed and Strain of Pig

The type of pig selected for organic production needs to do well under the conditions on the farm and produce meat of high quality at a profitable cost. Where acceptable under the local organic regulations, a pig of improved type (hybrid) should be first choice.

A wide range of genotypes of pigs is available for organic production internationally, displaying greatly different growth and carcass characteristics and responding differently to diet composition and level of feeding. Therefore the dietary regime and feeding programme should be modified according to the particular genotype of pig selected.

Use of older pure breeds allows the term ‘original’ or ‘traditional’ or ‘heritage’ to be applied to the meat products, which may be useful in marketing. These breeds may be better adapted to the region and may produce meat of better eating quality, but are likely to be unimproved in terms of growth performance and carcass quality. Therefore their meat may be produced at a relatively higher cost. An example is the Bísaro pig, which despite having lower growth rate, a less than ideal bodily conformation, and excessive adult weight and body size, is known to produce meat of excellent quality and suitable for processing (Santos e Silva et al.,

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