Online_Community_Centre: Heide's Blog

Why Manhattan's Green Roofs Don't Work--and How to Fix Them

Fri, 17 May 2013 21:25:14 GMT

Source - By Amy Kraft
City rooftops covered with vegetation are seen as a way to reduce the urban heat-island effect and cut energy usage--but so far, the results have been unimpressive. Two students are part of a research team that is trying to figure out how to maximize the benefits of green roofs. The problem has taken on practical significance as grass and other plants sprout on rooftops all over Manhattan and in other cities. For the past two years, New York City Mayor Michael Bloomberg’s PlaNYC initiative has offered tax abatements for green roof construction and grant money for projects to capture storm water. Rooftop gardens have the potential of lowering energy usage for heating and air-conditioning as well as reducing rainwater runoff, but their effectiveness is not well established.

Ecological Knowledge Offers Perspectives for Sustainable Agriculture

Wed, 01 May 2013 02:44:36 GMT

Source - A smart combination of different crops, such as beans and maize, can significantly cut the use of crop protection agents and at the same time reduce the need for fertilizers. Integrating ecological knowledge from nature with knowledge of crops opens up the prospect of a sustainable strategy that will increase yield per hectare at reduced environmental costs. This was the assertion of Prof Niels Anten in his inaugural speech upon accepting the post of Professor of Crop and Weed Ecology at Wageningen University on Monday 22 April.

Prof Anten sees great similarities between nature and a field full of crops. In both cases, plants are surrounded by numerous organisms such as weeds, pollinating insects, fungi, blights and diseases and their natural enemies, all engaged in the struggle for existence

In order to meet the food demand of nine billion people in 2050 and at the same time reduce our impact on the environment, such as the use of crop protection agents and developments leading to deforestation or desertification, we can no longer rely on synthetic pesticides and fertilizers alone. 'We need to conduct much more research to better understand how to utilize the potential provided by natural ecological processes,' said Professor Anten.

He points to recent research data showing that mixed crops require 20-40% less land to obtain the same total yields as mono-crops. There are several reasons for this. Different plant varieties make use of different growing times and different nutrients in the soil. They can also facilitate each other, for example by providing shade or making the soil more acidic, so that more phosphate is released. Also striking is the fact that mixed cultures are on average 40% less affected by diseases on average than single crops. In China there are even examples of a 90% reduction in diseases caused by fungi, leading to increased overall production.

'Mixed crops like these have a range of benefits. This makes it all the more surprising that so little research has been done into them,' observes Professor Anten. 'Our knowledge of plant breeding and crop physiology has resulted in crops which deliver maximum yield in monocultures. But there has been virtually no equivalent research conducted in mixed crops.'
In his inaugural address entitled 'Crop ecosystems as diverse playing fields,' Professor Niels Anten discusses the parallel development of two fields, the ecology of natural systems such as forests and the ecology of agriculture. Within his teaching and research remit of Crop and Weed Ecology, he will be looking at the connections between these areas of study for the benefit of sustainable crops with high yields.
Neighbours
In his speech, Anten talked at length about the way in which plants can detect each other's presence. Plants responses to neighbour plants can differ depending in whether these neighbours are: friends or a foes, a plant of the same species, a family member or a genetically identical clone, as in many monocultures in the West. A plant uses shade and filtering of sunlight by a neighbouring plant to detect its vicinity and size. It may respond with a growth spurt, towards the light. But the plant also differentiates between species. Maize growing beside wheat will produce deep roots to avoid those of the wheat, whereas if there are roots of beans close by, the maize roots will grow towards them. Plants from the same mother can also react differently to each other than plants from different mothers. So it appears that they recognise each other at the family level too.
Alien neighbouring plants include weeds, which pose an important threat to crop production. The use of herbicides is an important element of weed control, but also harmful to the environment, while more and more weeds are becoming resistant to these agents. 'We will therefore also need to look at other, more ecological solutions,' says Professor Anten. 'In short, in order to achieve a sustainable increase in food production, we will need to deploy all the weapons in our arsenal; among these, the opportunities produced by ecological interactions have to date been largely neglected.'

Study Shows Reproductive Effects of Pesticide Exposure Span Generations

Mon, 22 Apr 2013 22:48:42 GMT

Source - North Carolina State University researchers studying aquatic organisms called Daphnia have found that exposure to a chemical pesticide has impacts that span multiple generations -- causing the so-called "water fleas" to produce more male offspring, and causing reproductive problems in female offspring.

Nanoparticles Found in Everyday Items Can Inhibit Fat Storage: Gold Nanoparticles Accelerate Aging

Mon, 22 Apr 2013 22:41:32 GMT

Source - New research reveals that pure gold nanoparticles found in everyday items such as personal care products, as well as drug delivery, MRI contrast agents and solar cells can inhibit adipose (fat) storage and lead to accelerated aging and wrinkling, slowed wound healing and the onset of diabetes. The researchers, led by Tatsiana Mironava, a visiting assistant professor in the Department of Chemical and Molecular Engineering at Stony Brook University, detail their research in the journal Nanotoxicology.

Tests on rats suggest genetically modified foods pose health hazards

Wed, 13 Mar 2013 23:58:36 GMT

Source - By Louise Saran
When scientist Hussein Kaoud decided to test genetically modified food on rats, he produced results that were extremely alarming and corroborate the conclusions that some international, independent scientists have reached. Kaoud, of Cairo University’s Faculty of Veterinary Hygiene, fed nine groups of rats and mice different genetically modified foods — food made from organisms that have been biologically modified to incorporate genes with desired traits — and analyzed their physiological and psychological reactions.