Heavy metal-flavoured urban salads

Urban agriculture is gaining importance as a social means to produce food locally. However cities are well-known sources of pollution, which may contaminate urban crops. There is actually little knowledge on the degree of contamination of urban vegetables. Agronomists Vittori Antisari et al. analysed the heavy metal content of vegetables in the city of Bologna, Italy. They found that the most contaminated vegetables grew near roads, which is explained by traffic pollution.

 

Fertilisation should take into account regional climate for food security in China

Crop yields depend on many factors such as fertiliser amount, rainfall and temperature. In order to better understand which factors rule crop yields, soil scientists Wang et al. analysed the Chinese Statistical Yearbooks including data of the major grain-producing regions of China from 1993 to 2013. They found that current fertilising strategies should be improved by taking into account regional climate conditions.

 

Baby plants and root-friendly bacteria improve potato cultivation

Common belief tells that bacteria are sources of illnesses for living organisms. That is not true for plants, which can benfit from the help of small friends in the form of bacteria. For instance the root-friendly Azospirillum bacteria enhance the growth and adaptation of plants. Agronomists Tkachenko et al. show that the cultivation of baby plants with the Azospirillum brasilense bacterial species improve potato growth, development, and survival in the field, leading to an increase of 45% of tuber yield, on the average.

 

Organic farming of cereal-legume intercrops for food security

Agriculture faces two major issues worldwide, producing safe food without the use of toxic pesticides, and producing more food to meet the projected population increase of 9 billion by 2050. Ecological intensification is a promising solution because ecosystem services such as the use of natural enemies to kill undesired pests is a safe alternative to pesticides. Agonomists Bedoussac et al. reviewed the results of 58 organic farming experiments of cereal-grain legume intercropping in Europe. They found that intercropping gives higher yields, protein and money that sole crops.

 

Stubble grazing sustains soil quality and carbon in wheat crop drylands

Stubble grazing is traditionally perceived as a practice that degrades soils. As potential consequence is the decrease of soil carbon, which is transferred to the atmosphere as CO2, a greenhouse gas. To check this assumption scientists Stavi et al. studied stubble grazing following wheat crops in drylands. They found that moderate stubble grazing does not degrade the soil and does not decrease the quantity of soil organic carbon.

 

Smart fertilisers for fit rice and less water pollution by nitrates

Classical fertilisers have a low efficiency becasue only a minor part of the fertiliser reaches plant roots. As a consequence a major part of classical fertilisers escapes rapidly toward groundwater, thus polluting drinking water with nitrates. Research has therefore invented controlled-released fertilizers to feed the plant slowly in the long run. Controlled-released fertilizers include polymeric material – a kind of plastic – to slow down fertiliser feeding. In other words controlled-released fertilizers are comparable to pasta that provide energy slowly in the long run, whereas classical fertilisers are similar to sweets that provide high energy fast. Agronomists Wang et al. have evidenced improved nitrogen uptake and reduced nitrogen loss using a polymer-coated urea fertiliser to grow flooded rice in southeast China.

 

A new tool to optimize fodder production under climate change

Milk and meat production highly depends on the availability of fodder, which is obtained by mowing grass in summer wet conditions. However, grass production is projected to decrease due to lower rainfall in the summer. The grassland surface is indeed already decreasing worldwide. In order to improve grassland management Dusseux et al. designed a new model named PaturMata to study grassland production under climate change.

 

How to identify soil microbes of agricultural interest ?

Soil contains a huge number of very diverse living organisms such as worms, fungi and bacteria. Many of these organisms work for the benefit of agriculture by recycling organic water, cleaning pollution and transforming atmospheric dinitrogen gas into free fertilisers. So far soil organisms are underutilised because many organisms are not even identified, and their beneficial expertise is often unknown. Microbiologists Degrune et. al set up a new method that allows to distiguish microbial communities in soils cultivated with different cropping practices.

 

Food is contaminated by nicotine from tobacco

The toxic alkaloid nicotine, a natural component of tobacco, has been detected in many food crops, medicinal plants and plant food such as spices and teas, thus threatening food security. So far the origin of such nicotine contamination was unknown. Plant scientists Selmar et al. studied the possible contamination of peppermint by soils enriched in nicotine from cigarette residues. They also checked whether peppermint could take up nicotine from cigarette smoke. They found that peppermint take up nicotine from soil and from smoke. The tobacco industry and users are therefore responsible, at least partly, by the wide contamination of many crops and food by nicotine.  Selmar et al. also explain that the passive incorporation and metabolisation of nicotine by peppermint is surprising and unprecedented with respect to current knowledge in allelopathy.

 

New indicator for better N fertilisation in crop-livestock farms

Nitrogen (N) fertilisation is essential for crop and food production. However actual N fertilisation is not often very efficient and can induce pollution, e.g. by nitrates. There is therefore a need for indicators to compare farming systems. Scientists Godinot et al. developed a new indicator named ‘relative N efficiency’, which is specifically well suited to compare farming systems with different proportions of animals and crops.