Science Round-up: Danish agriculture still using too much fertiliser – The Post

Science Round-up: Danish agriculture still using too much fertiliser

In other stories, plastic can also be beneficial when it helps capture more sunlight, new knowledge emerges about the origins of Native Americans, and some genes can be a double-edged sword

The lovely smell of pesticide spraying in the morning (photo: Maasaak)
June 6th, 2019 12:30 pm| by Stephen Gadd

New research from the Danish centre for food and agriculture at Aarhus University reveals that more and more phosphates and nitrogen is being used by farmers that is not being utilised by crops or animals.

There is a high risk that the excess fertiliser ends up in lakes, rivers and streams, causing an explosion of algae growth that leads to hypoxia when the dead algae is broken down by bacteria.

The increase has been especially marked since the end of 2015, when the government and Dansk Folkeparti agreed a package of measures that gave farmers the possibility to use fertilisers up to what is economically optimal instead of previously 80 percent of the optimal, reports Ingeniøren.

Gassing up
The use of excess nitrogen, phosphates and potassium fell between the end of the 1990s and the mid-2000s.

“The excess has been rising again over the last couple of years primarily as a consequence of adopting the package and, by doing so, phasing out norm reductions,” the university’s report states.

As well as the fertiliser problem there is also a slight increase in the amount of ammonia evaporating into the atmosphere, despite Denmark pledging to reduce it.


Plastic foil cheap solution to concentrate Sun’s warmth
Most solar energy panels use a system of mirrors to concentrate the sun and this makes them expensive to produce. However, a newly-developed plastic foil by the Danish company Heliac could change all that, reports Ingeniøren. In May a new solar energy system was opened in Lendemarke on the island of Møn consisting of solar panels made of normal window glass with the plastic foil underneath. The foil is half as expensive as the mirrors to produce and is also more effective at catching the Sun’s rays. “The foil is able to turn 84 percent of the sunlight into warmth. The best mirror systems can do around 79 percent,” said Heliac administrative director Henrik Pranov.

New ancestors to Native Americans revealed
Archaeologists have long been interested in a 31,000 year-old camp near the Yana River in Siberia, and a number of important finds have been made since 2001. Before the camp was discovered it was not thought people had spread so far north before 12-13,000 years ago. However, DNA sequencing of the milk teeth from two children carried out by a research team led by Eske Willerslev from the University of Copenhagen reveals that the Yana people, now dubbed Ancient North Siberians, were there 31,000 years ago, reports Videnskab.dk. The results of the study, recently published in Nature, show that the Yana people are forefathers to present-day Siberians and Native Americans.

You win some, you lose some
New research published in Nature Medicine reveals that a gene that protects people from HIV also seems to be associated with premature death. The University of California, Berkley research team, which included Rasmus Nielsen from the University of Copenhagen’s geogenetic centre, used genetic sequences from hundreds of thousands of people and found that people with two copies of a variant of the CCR5 gene had a 21 percent higher chance of dying before they reached the age of 76 than those with one or no copies of the gene.

Membrane technology tested by waterworks
Pesticides in drinking water are an increasing problem, and at present activated carbon is the most widespread technology used to clean Danish drinking water. However, this is unable to filter out all types of pesticides. Membrane technology could provide the answer, reports Ingeniøren. Two Danish waterworks – one in Sejrø in Kalundborg Municipality and one in Yderby Lyng in Odsherred Municipality – are already trying it out. The membrane was originally installed to minimise salt levels but they have also been found to remove pesticides and pesticide residues.