Nitrogen-based fertilisers have helped all but eradicate famine in large parts of the world. But reactive nitrogen in circulation has now doubled. Owen Gaffney asks, what effect is this having on the carbon cycle?

Intensive agriculture and excessive use of external inputs lead to degradation of soil, water and genetic resources. Widespread soil erosion, nutrient mining, depleting water table and eroding biodiversity are the global concern which are threatening the food security and livelihood opportunities of the farmers, especially the poor and underprivileged.

The concept of food security has evolved during the last three decades to include not only food availability, but also economic access to food and the biological absorption of food in the body. The author discusses in this paper the challenge of achieving sustainable advances in farm productivity, leading to an "ever-green revolution" in the fields of farm families with small holdings.

Agriculture growth and instability have remained the subject of intense debate in the agricultural economics literature in India. While the need for increasing agricultural production or growth are obvious, the increase in instability in agricultural production is considered adverse for several reasons.

Systems dynamics, cellular automata, agent-based modeling, and network analyses have been used in population, land use, and transport planning models.