Towards Greening of Urban Landscape

Abstract

Rapid urbanization since 1950, both in developed and developing countries, has led to a large-scale conversion of prime agricultural/farm lands to build up areas under concrete and asphalt. The associated disturbance of the ecosystem structure and functions leads to disruption in cycling of elements (C, N, P), perturbation of the hydrologic cycle and the energy budget, and depletion of the ecosystem C pool. The global rate of urbanization is about 2 Mha/year. Land area under urban centers is estimated at about 24 Mha (2.6% of the total land area) in the U.S.A. Urban centers consume a large proportion of total energy, transport fuel, food, water and other consumable, and are thus principal sources of gaseous emissions. Nonetheless, the green areas within the urban centers (i.e., home lawns, turfs, urban forests, and urban agriculture) have the technical potential to off-set some of the gaseous emissions. This strategy is to enhance the net ecosystem C budget of the green area by reducing the hidden C costs of inputs, enhance above and below ground biomass production, and restore abandoned lands and buildings for agricultural production. Sustaining agronomic production implies improving soil structure and tilth, alleviating soil compaction, creating favorable water and nutrient regimes, and increasing soil organic C pool and especially its depth distribution in the sub-soil.