Night-soil (human waste) has been considered a valuable agricultural resource since ancient times. When handled safely, its use can contribute to reducing soil degradation and water scarcity in the areas like the Lahaul valley. Despite such known benefits its use is now decreasing with modernisation. Recognising this, the G.B. Pant Institute in India has been taking steps to promote the use of night-soil as one of the organic farming practices promoted in the region.

Potassium release kinetics was investigated in soils drawn from plots of a long term fertilizer experiment that had been receiving different rates of K. Non exchangeable K release was higher in soils that were receiving organic and inorganic fertilizers than the soils not dressed with K. The amount of non exchangeable K release was faster initially and it slowed down afterwards.

Green revolution in India has bypassed the remote places like hills. Farmers who are struggling for survival under unfavorable conditions like hills need focus. In Uttarakhand, only 13.62 per cent is the net cultivated area. Agriculture in Uttarakhand is primarily confined to lower and mid hill regions and is basically subsistence in nature.

A former US Environmental Protection Agency (EPA) scientist is suing the agency's officials and researchers at the University of Georgia in Athens, alleging that they manufactured and published false data to support the use of potentially harmful sewage sludges as fertilizers. The sludges have been linked to health problems in humans and cattle

Some 30 years ago, as the United States began to tighten its environmental regulations on residential and industrial wastewater, operators of sewage-treatment plants embraced what seemed an eminently sensible idea. They decided to take the rich organic sludge left over after clean water is extracted and sell it to farmers as fertilizer. The programme might well be as sensible as it seems. It is possible that the millions of tonnes of sludge being spread across the rural landscape contain no significant levels of toxic chemicals, heavy metals or disease-causing organisms.

In a recent perspective, "Food security under climate change" (1 February, P. 580), M.E. Brown and C.C. Funk conclude that improved seed, fertilizer, land use and governance lead to food security. I find these claims highly questionable. The green revolution model (monocultures of improved crops supported through high levels of agrochemical and other inputs) has done much to increase agricultural productivity. It does little, if anything, to increase food security. (Letters)

More than a billion acres have been planted with genetically engineered crops in the USA since 1996, but we do not fully know their ecological costs and benefits.