Green roofs recover green spaces in urban areas. Green roofs benefit the public, farmers and wildlife. Green roofs reduce stormwater runoff, mitigate urban heat island effects, absorb dust and smog, sequester CO2, produce O2, create space for food production, and provide natural habitat for animals and plants. Li and Babcock review the economic and environmental benefits of green roofs.
A catch crop is a crop planted between two regular crops grown in successive seasons or between two rows of crops in the same season. Catch crops are used in particular to reduce soil erosion and fertiliser leaching that occur when the soil surface is not planted. For instance nitrogen catch crops feed on nitrates and thus recycle soil nitrogen and decrease water pollution by nitrates. Catch crops are therefore a way to reduce the use of costly fertilisers. Tuulos et al. show that winter turnip rape, an oilseed crucifer, is an effective nitrogen catch crop adapted to the Nordic climate.
The glasshouse whitefly Trialeurodes vaporariorum is major worldwide pest of glasshouse crops. It does its damage by excreting plant sap which then grows black sooty mold fungus which spoils the appearance of the product. Tosh et al. reasoned that since plant volatiles – the odour of a plant – are usually harmless to humans but often harmful to insects, and since the glasshouse is an enclosed space, plant volatiles could be used to control whiteflies. The authors attempted to apply the well know ‘confusion effect’ – confusing animals with too much information – by bombarding the whiteflies with a super-abundance of host plant volatiles while they are feeding on tomato plants. Unfortunately the confusion effect does not have a strong impact on the whitefly. The confusion effect may be used in combination with other odour-based control methods for the glasshouse whitefly, but it is unlikely to be sufficient as a stand-alone control method.
Global warming is moving plant and animal species toward cooler areas, thus impacting agriculture and food production. In particular livestock farmers should adapt their pratices to climate changes, but there is actually few evidence of shepherd adaptation. Rigolot et al. surveyed shepherds from the French Auvergne. They found that shepherds clearly modify their use of collective mountain pastures in summer.
Urban agriculture is developping fast because more and more people live in urban areas. Moreover urban food production is local, cheaper and social. There is therefore a need for advanced indoor techniques to cultivate plants. Indoor techniques will also benefits people leaving in far northern and southern latitudes due to long yearly periods with no or little sunlight. As plants prefer some light colours, using specific colours might improve plant growth. Sabzalian et al. tested red, blue and white light-emitting diode (LED) to grow mint, lentil, basil, and four ornamental plants. Their experiments unraveled surprising performance and production of vegetables and ornamental plants.
Drought is decreasing wheat yields in semi-arid regions. This issue may be partly solved by better forecasting wheat production. Bregaglio et al. improved wheat forecast by adapting two wheat models to the specific agro-climatic of Morocco.
Farmer seed exchange is essential for food security because seed exchange maintains crop biodiversity and, in turn, biodiverse crops survive better climate changes and pest infection. However, actually we do not understand exactly how seed exchange networks induce crop diversity. A study by Pautasso explains why individual farmers do not cultivate all varieties present in a region or a village.
Canola is a major crop for food as canola oil, and energy as biodiesel. Many factors control the yield of canola, but there is actually little knowledge on the influence of the spatial arrangement of canola plants. Gan et al. shows that uniform canola stands increase seed yield by up to 32% at low-yielding sites and by up to 20% at the high-yielding sites, compared to non-uniform plant stands. Yields can thus be increased by more uniformity, regardless of environmental conditions.
Food security is increased and poverty is reduced in sub-Saharan African by cultivation of fruits and vegetables. However, up to 100% yield losses are due to insects and diseases. Misuse, overuse and use of unauthorized pesticides are common among small farmers. De Bon et al. presents solutions based on agroecology and integrated pest management (IPM) to reduce pesticide use. In particular ecological methods and good pesticide management should be taught to farmers and other stakeholders.
Rice is a major food worlwide. The cost of rice fertilisation using mined fertilisers such as nitrogen (N), phosphorus (P), and potassium (K) amounts to 30-35% of the cropping cost, and is still increasing. This issue could be solved by replacing mined fertiliser by biofertilisers that contain microbes helping the plant to grow, so-called ‘plant growth-promoting microorganisms’. The report by Rose et al. indeed show that inoculant biofertilizers can replace up to 52% of mined nitrogen fertiliser without loss of yield.