Current trends and challenges in the synthesis and applications of chitosan-based nanocomposites for plants: A review.

Chitosan, a low-cost and multipurpose polymer with numerous desired physicochemical and biological properties has been tested for various applications in agriculture, pharmacy, and biomedicine industries. The availability of functional groups along the backbone makes chitosan readily available for other polymers and metal ions to form bio-nanocomposites. Different types of chitosan-based nanocomposites have been designed and tested for the enhancement of chitosan efficiency and ultimately widening the application areas of chitosan in plants. These nanocomposites serve different purposes such as eliciting plant's defence systems against different threats (pathogen attack), antimicrobial agent against bacteria, fungi and viruses, enhancement of nutrient uptake by plants, control release of micro/macronutrients, fungicides and herbicides. In this review, an extensive outlook has been provided (mainly in the last five years) to recent trends and advances in the fabrication and application of chitosan-based composites. Finally, current challenges and future development opportunities of chitosan-based nanocomposites for plants are discussed.

Progress of modern agricultural chemistry and future prospects.

Agriculture is facing an enormous challenge: it must ensure that enough high-quality food is available to meet the needs of a continually growing population. Current and future agronomic production of food, feed, fuel and fibre requires innovative solutions for existing and future challenges, such as climate change, resistance to pests, increased regulatory demands, renewable raw materials or requirements resulting from food chain partnerships. Modern agricultural chemistry has to support farmers to manage these tasks. Today, the so-called 'side effects' of agrochemicals regarding yield and quality are gaining more importance. Agrochemical companies with a strong research and development focus will have the opportunity to shape the future of agriculture by delivering innovative integrated solutions. This review gives a comprehensive overview of the innovative products launched over the past 10 years and describes the progress of modern agricultural chemistry and its future prospects.

Nicotinic acetylcholine receptor agonists: a milestone for modern crop protection.

The destruction of crops by invertebrate pests is a major threat against a background of a continuously rising demand in food supply for a growing world population. Therefore, efficient crop protection measures in a vast range of agricultural settings are of utmost importance to guarantee sustainable yields. The discovery of synthetic agonists selectively addressing the nicotinic acetylcholine receptors (nAChRs), located in the central nervous system of insects, for use as insecticides was a major milestone in applied crop protection research. These compounds, as a result of their high target specificity and versatility in application methods, opened a new innovative era in the control of some of the world's most devastating insect pests. These insecticides also contributed massively to extending our knowledge of the biochemistry of insect nicotinic acetylcholine receptors. The global economic success of synthetic nAChR agonists as insecticides renders the nicotinic acetylcholine receptor still one of the most attractive target sites for exploration in insecticide discovery.

Current challenges and trends in the discovery of agrochemicals.

Crop protection chemistry has come a long way from its "alchemic" beginnings in the late 19th century to a high-tech science that supports the sustainable production of food, feed, and fiber for a rapidly growing population. Cutting-edge developments in the design and synthesis of agrochemicals help to tackle today's challenges of weed and pest resistance, higher regulatory safety margins, and higher cost of goods with the invention of selective, environmentally benign, low use rate, and cost-effective active ingredients.

Agricultural chemistry and bioenergy.

Renewed interest in converting biomass to biofuels such as ethanol, other forms of bioenergy, and bioenergy byproducts or coproducts of commercial value opens opportunities for chemists, including agricultural chemists and related disciplines. Applications include feedstock characterization and quantification of structural changes resulting from genetic modification and of the intermediates formed during enzymatic and chemical processing; development of improved processes for utilizing chemical coproducts such as lactic acid and glycerol; development of alternative biofuels such as methanol, butanol, and hydrogen; and ways to reduce greenhouse gas emission and/or use carbon dioxide beneficially. Chemists will also be heavily involved in detailing the phytochemical composition of alternative energy crops and genetically improved crops. A resurgence of demand for agricultural chemistry and related disciplines argues for increasing output through targeted programs and on-the-job training.

Evolución geoquímica y problemática del uso del acuífero del Arroyo Marín (Archidona-Málaga) / Geochemical evolution and the problems arising from the use of water from the Arroyo Marín aquifer (Archidona-Málaga)

El estudio de las facies químicas del Arroyo Marín, afl uente más importante del río Guadalhorce, se justifi ca por el carácter selenitoso de las aguas aportadas por los numerosos manantiales existentes en la margen izquierda del arroyo y que modifi can notablemente las características organolépticas del río Guadalhorce que nutre de agua a la provincia de Málaga. Además, desde el punto de vista sanitario se aprecian altas concentraciones de magnesio y nitratos, que desaconsejan su consumo humano, hecho importante por ser una zona de tránsito para excursionistas. El acuífero analizado está marcado a su vez por la actividad del imponente karst de yesos de Archidona, cuya cuenca de recepción tiene numerosas dolinas y las aguas drenan por conexiones subterráneas laberínticas, poco conocidas, que consolidan las facies hidroquímicas del suelo

The chemical facies from the stream Arroyo Marin, the largest tributary to the river Guadalhorce, is considered to be worthy of study, due to the high selenium content in the waters emanating from the numerous springs found to the left margin of the stream. These waters considerably modify the organoleptic characteristics of the river Guadalhorce, which serves as an important source of water for the province of Malaga. Furthermore, from a health safety point of view, these waters present high concentrations of magnesium and nitrate, rendering them unsuitable for human consumption. This is an important consideration, given that the areas is popular as a country treking destination. The aquifer under analysis is also characterised by the imposing activity of the Archidona gypsum karst, whose rainfall cachment area has numerous sinkholes. The water is subsequently drained into the ground through a little known laberynth of subterranean conections, which help determine the hydrochemical facies of the terrain

Recent advances in agrochemical formulation.

This review will describe some of the changes occurring in formulation types employed and the further trends that are driving technologies. These will be illustrated by examples of water-based dispersion formulation technology for oil-in-water emulsions (EW) and suspension-emulsions (SE) as well as other formulation types such as emulsifiable gel and dry product formulations where new techniques of formulation, often combining polymers and surfactants in novel ways have resulted in significant formulation and sometimes processing improvements.

Twenty five years of reference material activity at Agriculture and Agri-Food Canada.

In the mid 1970s, the available RMs, notably Bowen's Kale and Orchard Leaves and Bovine liver from National Bureau of Standards (NBS), although of great benefit, were overwhelmingly insufficiently representative, in respect of matrix and elemental composition, of the wide range of natural products submitted for analysis and in worldwide commerce. To provide additional coverage, an RM development project was initiated with input from cooperating analysts leading to an Agriculture and Agri-Food Canada/National Institute of Standards and Technology (NIST) cooperative venture and development of a total of 12 different agricultural/food RMs. With a total of 303 concentration values for 34 elements and a wide range of matrix components such as ash, silica, protein, fat, carbohydrate and fiber, these RMs significantly augment the world repertoire of biological control materials. A final material under consideration is a highly reliable, discrete, synthetic RM for quality control and calibration. This paper summarizes the research and developmental activities undertaken during the past quarter of a century related to RM development at Agriculture and Agri-Food Canada and includes a short historical background, conceptual considerations, preparation, physical characterization, homogeneity estimation, chemical characterization, calculation of recommended reference values and associated uncertainties, methodology development and application, and performance of inorganic analytical methods in a multielement, multilaboratory, collaborative characterization campaign.