ABSTRACT
The Southern and Eastern National Capital Region of Delhi is experiencing diversified and expanding urbanization as in million-plus cities of the area the urban sprawl activities are more frequent than the urban densification activities. The progressing sprawl of residential and construction sites is transforming the regional ecosystems and hampering the generation of ecosystem services of fundamental importance, i.e. the benefits and services that we get directly or indirectly from the ecosystem functioning. The Costanza et al., (2014) approach shows that the ecosystem services value has decreased at US$ 56 ha-1 year-1 (0.09% per year) and absolute and cumulative losses are estimated US$ 285.4 ha-1 year-1 and US$ 502.8 ha-1 year-1, respectively. The ecosystem service values assessment shows that the ecosystem services like climate regulation and recreation have increased but food production, genetic resources, water supply, soil formation, raw materials and waste treatment have decreased over the time. The use of alternative ecosystem value coefficient shows that the estimated value of the ecosystem service value changed from a low of 0.005% for 1% change in the value of the forest coefficient, to a high of 0.749% for a 1% change in the value of the agricultural land coefficient. For each land use/land cover category, the sensitivity analysis reflects the inelasticity or robustness of the estimated ecosystem value with respect to the value coefficient. Overall, prioritizing the conservation and enrichment of natural and man-made ecosystems of critical value will lead to sustainable development of urban ecosystems.
ABSTRACT
Increased use of nitrogenous fertilizers in the intensively cultivated rice (Oryza sativa)-wheat (Triticum aestivum) cropping system (covers a 13.5-ha m area in South Asia) has led to the concentration of nitrates (NO(3)-N) in the groundwater (GW) in Haryana State of India. Six districts from the freshwater zone were selected to identify factors affecting NO(3)-N enrichment in GW. Water and soil samples were collected from 1,580 locations and analyzed for their chemical properties. About 3% (26,796, and 10,588 ha) of the area was estimated to be under moderately high (7.5-10 mg l( -1)) and high (>10 mg l( -1)) risk categories, respectively. The results revealed that NO(3)-N was 10-50% higher during the pre-monsoon season than in the monsoon season. Nitrate-N decreased with the increase in aquifer depth (r (2) = 0.99). Spatial and proximity analyses using ArcGIS (9.2) revealed that (1) clay material in surface and sub-surface texture restricts N leaching, (2) piedmont and rolling plains act as an N sink, and (3) perennial rivers bring a dilution effect whereas seasonal rivers provide favorable conditions for NO(3) (-) enrichment. The study concludes that chemical N fertilizers applied in agro-ecosystems are not the sole factor determining the NO(3) in groundwater; rather, it is an integrated process governed by several other factors including physical and chemical properties of soils, proximity and type of river, and geomorphologic and geographical aspects. Therefore, future studies should adopt larger area (at least watershed scale) to understand the mechanistic pathways of NO(3) enrichment in groundwater and interactive role of the natural drainage system and surrounding physical features. In addition, the study also presents a conceptual framework to describe the process of nitrate formation and leaching in piedmont plains and its transportation to the mid-plain zone.
