Phosphorus is a non-renewable and strategic resource essential to produce food and other goods through. Present methods to measure soil phosphorus lack accuracy. Recena et al. designed a new method taking into account clay content and pH to make accurate predictions of phosphorus threshold values. This will contribute to a more sustainable use of phosphorus resource in agriculture.
Urban gardens are rapidly spreading in cities because people want healthier, self-grown food. However, cities are often highly polluted by atmospheric pollutants. Soils used for plant growth may also contain heavy metals. Agronomists Pennisi et al. grew vegetables with and without soil and found that soilless vegetables contained 70% less chromium, 61% less copper, 45% less cadmium and 81% less nickel. They conclude that, unexpectedly, soil is the major pollution source of urban vegetables, not air.
Tobacco is an industrial crop traditionally used for manufacturing cigarettes but due to European subsidies restriction, an alternative use should be found. Tobacco could be used as an oilseed crop with an oil yield ranging from 30 to 40% of seed dry weight. Grisan et al. review the performance of tobacco cultivar Solaris in Italy. Seed production was evaluated to be 1.1 – 1.8 t/ha, with an oil yield up to 0.59 t/ha. In North Est Italy two seed harvests determined a total seed yield of 4.5 t/ha, from which 1.48 t of oil/ha could be obtained.
In Malawi, the rise of pigeonpea and cassava production has created conflicts. Farmers in Malawi cut pigeonpea and sorghum to extend production for more than one growing season. They also grow cassava, a perennial food crop that has a proven track record of abating hunger. Rogé et al. show that research is needed to evaluate trade-offs of ratooned systems, to further develop markets for smallholder farmers, and to breed ratoon crops with yield stability and resistance to diseases and pests.
Domestic wastewaters are used to irrigate soils, thus saving pristine waters. However wastewater contains human enteric viruses that may contaminate the atmosphere after wastewater spraying. Scientists Girardin et al. found that 11-89% of murine mengoviruses applied to the soil were aerosolized during the first half hour. They have developed a model to help policymakers refine standards governing wastewater reuse in irrigation.
Perennial crops are plants that live for more than two years. They reduce fertilizer input and soil erosion, and favor carbon sequestration. However perennials are declining due to soil pests and pathogens. Vukicevich et al. propose to use cover crops to select soil microbial communities that will benefit perennial crops.
The industrialization of agriculture has often led to lower efficiency, pollution and greater dependence on non-renewable energy. Organic agriculture and traditional agriculture are thus potential alternatives. Agronomist Pérez Neira studied the energetic and economic behavior of cacao in traditional, semi-intensive traditional, technified and organic farms in Ecuador. Results show that well-managed organic farms improve energy efficiency by comparison with technified or semi-intensive management strategies, and also improves the economic performance.
Biofortification of staple crops with zinc is a strategy for overcoming human zinc deficiency. Agronomists Wang et al. calculated the cost of agronomic biofortification of wheat with zinc in China. Results show that the price is high when zinc is sprayed alone. Whereas the cost is cheaper, from US$ 41 to US$ 108, when zinc is combined with routine pesticide management to reduce labor cost.
Crop-livestock farms are declining across Europe despite the fact that they are theoretically sustainable. Agronomists Martin et al. evidenced collaborations among farms and farmers, such as the direct exchange of raw materials. They propose to set up participatory workshops to improve farm-farm collaborations.
Global warming is induced by several factors, notably by the emission of greenhouse gases such as carbon dioxide (CO2) and nitrous oxide (N2O) by some agricultural practices. Agronomists Vermue et al. measured the nitrous oxide emissions of various weed management options. They found the highest emissions, of 5226 g per hectare, in the no tillage system, versus 177 g for intensive tillage. Most N2O emissions occurred in spring.