Feature Article

Numerous reports have emphasized the need for major changes in the global food system: agriculture must meet the twin challenge of feeding a growing population, with rising demand for meat and high-calorie diets, while simultaneously minimizing its global environmental impacts. Organic farming—a system aimed at producing food with minimal harm to ecosystems, animals or humans—is often proposed as a solution.

A meta-analysis of agricultural systems shows that organic yields are mostly lower than those from conventional farming, but that organic crops perform well in some contexts. Agricultural scientists discuss whether the conclusions of the study should change farming practices and management.

Recycling plutonium is dangerous and costly. Britain should take the lead on direct disposal, say Frank von Hippel, Rodney Ewing, Richard Garwin and Allison Macfarlane.

Clouds and aerosol particles have bedevilled climate modellers for decades. Now researchers are starting to gain the upper hand.

For villagers in Mwandama, Malawi, visiting a health worker used to mean a daunting 40-kilometre round trip on foot. So the medical centre that was built in the area as part of the Millennium Villages Project (MVP) last year has improved their quality of life — and their health. Research published this week suggests that the MVP has significantly reduced infant mortality at sites across Africa.

Rothamsted's genetically engineered wheat should be allowed to grow. (Editorial)

International development experts say that the Millennium Villages Project's claims of progress should be interpreted with caution. (Editorial)

Soil organic carbon (SOC) is the largest among three major carbon pools of global ecosystems. During the past few years, global warming and forcible land-use changes have resulted in a huge loss of this major carbon pool and as a consequence, concentration of atmospheric CO2 has increased. To mitigate the potential risks arising from atmospheric abundance of CO2, adoption of carbon sequestration strategies at different landscape scales is a major option. For this

Clay minerals are natural materials well known for their role in retention and persistence of organic and inorganic compounds in soil. Clay minerals are being modified through different processes to alter their charge and surface properties tailored for specific purposes. Modified clays in general include pillared layered clays, organoclays, nanocomposites, acid and salt-induced and thermally and mechanically induced modified clays. Pillared organoclays and nanocomposites constitute a novel class of materials, mainly one kind of modification of expanding 2 : 1 clay minerals.