Producing more food with less land is a serious issue. Indeed the world agricultural area, which amounts to about 46% of earth surface, is actually decreasing whereas global food demand is projected to increase up to 70% in 2050. Therefore there is a need for a better optimisation of agricultural land. Agronomists Memmah et al. review 38 case studies that optimise agricultural landscape in 16 countries using using metaheuristics algorithms.
ASD
Do not ditch birds
For higher yields industrial agriculture has been removing all landscape diversity such as ditches and hedges, which has led in the long run to many adverse impacts such as loss of plant and animal diversity, soil erosion, water pollution, and, paradoxically, loss of plant nutrients. Agronomists Dollinger et al. review the major ecosystem services provided by ditches, e.g. flood regulation, water purification, pesticide retention and wildlife conservation. A striking example is that the occurrence of ditches can double the number of bird species in crop fields.
The roots of free fertilisation
Nitrogen (N) is a major element that plant need for growth. Legumes are nitrogen-rich plants that are named ‘green fertilisers’ because legume residues enrich the soil in nitrogen after plant death. This fertilising effect is actually assessed by measuring shoot N concentrations, which does not take into account root contribution. Agronomists Carranca et al. indeed found that roots contain 7 – 11% of total legume N. The power of legumes as fertilisers for the next crop is thus underestimated.
Worms are farmer’s friends
Most current agricultural practices are not sustainable. For instance the discharge of livestock manure is polluting waters. A solution to avoid manure disposal is to compost manure with maize and worms, so-called vermicomposting. Scientists Guo et al. studied the economical benefits of vermicomposting cattle manure with maize. They found that vermicomposting increases agricultural benefits by 304% compared to classical composting.
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.
