Little is known about nutrient fluxes and nutrient-use efficiencies in urban and peri-urban agriculture (UPA) of rapidly expanding cities in developing countries. Therefore, horizontal flows of carbon (C), nitrogen (N), phosphorus (P), and potassium (K) as well as leaching losses of mineral N and P were measured over 2 years in three representative agricultural production systems of Kabul. These comprised 21 gardens and 18 fields dedicated to vegetable farming, cereal farming, and table-grape production (vineyards). Across sites (fields and gardens) biennial inputs averaged 375 kg N ha -1 , 155 kg P ha -1 , 145 kg K ha -1 , and 15 kg C ha -1 while with harvests 305 kg N ha -1 , 40 kg P ha -1 , 330 kg K ha -1 , and 7 kg C ha -1 were removed. In vegetable gardens, biennial net balances were 80 kg N ha -1 , 75 kg P ha -1 , -205 kg K ha -1 , and 4 kg C ha -1 , whereas in cereal farming biennial horizontal balances amounted to -155 kg N ha -1 , 20 kg P ha -1 , -355 kg K ha -1 , and 5 kg C ha -1 . In vineyards, corresponding values were 295 kg N ha -1 , 235 kg P ha -1 , 5 kg K ha -1 , and 3 kg C ha -1 . Annual leaching losses in two selected vegetable gardens varied from 70 to 205 kg N ha -1 and from 5 to 10 kg P ha -1 . Night soil and irrigation water were the major sources among the applied nutrient inputs in all studied farming systems, contributing on average 12% and 25% to total N, 22% and 12% to total P, 41% and 53% to total K, and 79% and 10% to total C, respectively. The results suggest that soils in extensive cereal fields are at risk of N and K depletion and in vegetable gardens of K depletion, while vineyards may be oversupplied with nutrients possibly contributing to groundwater contamination. This merits verification. Figure 1: Map of Greater Kabul in Afghanistan showing the location of the selected vegetable, cereal, and grape research sites.J . Plant Nutr. Soil Sci. 2011, 174, 942-951 Nutrient balances in urban and peri-urban agriculture 943

Little is known about the economics of urban and peri-urban agriculture in Kabul, Afghanistan. This study therefore aimed to investigate the profitability of 15 mixed cropping farms with a total of 42 farm plots that were selected from a survey of 100 households (HHs). The sample represented the three dominant farm types: cereal producers (15 plots), vegetable farmers (15 plots) and grape producers (12 plots). A cost-revenue analysis of all inputs and outputs (costs of tillage, seed where applicable, weeding, harvesting, casual labour, machinery use, pruning, pesticides and of revenue from produce sold) over two years showed major differences in net HH income. Differences were largely due to production type and crops grown and reflected differences in market prices for produce. Cereal production yielded a total bi-annual revenue of 9630 US$ ha −1 , and a gross margin and a net profit of 8770 US$ ha −1 . Vegetable farming gave an average bi-annual revenue of 27 900 US$ ha −1 , a gross margin of 26 330 US$ ha −1 and a net profit of 25 530 US$ ha −1 . Surprisingly, vineyards generated the lowest returns with a revenue of 5400 US$ ha −1 , and a gross margin and a net profit of 4480 US$ ha −1 . The results suggest that among the production systems studied vegetable cultivation was most profitable given its direct linkage to city market demands, rather stable prices and much shorter growing season than for cereals and grapes. In addition, the inflow of wheat and grapes from rural areas into the city negatively affects local producer revenues. If vineyards are to be maintained in the city surroundings, incentives such as subsidized credit may need to be made available to producers. I N T RO D U C T I O N

Increasing concentration of nitrous oxide (N2O) in global atmosphere can perturb the ecological balance affecting climate and human life. South Asia, one of the worlds’ most populous regions, is a hotspot for N2O emission. Though agriculture traditionally dominated the region, economic activities are rapidly shifting towards industry and energy services that may take front seat in N2O emission in future. Yet, few attempts have been made to estimate long term direct N2O emission from fuel combustion for the different energy consuming sectors in the South Asian region. Therefore, the present study developed a comprehensive sectoral N2O emission inventory for South Asian countries for the time period of 1990-2017 with projections till 2041. It revealed that average N2O emission from fuel combustion in the South Asia region is about 40.96 Gg yr-1 with a possible uncertainty of ± 12 Gg yr-1 showing an increase of more than 100% from 1990 to 2017. Although, India is the major contributor with an average of 34 Gg yr-1 of N2O emission, in terms of growth small countries like Bhutan and Maldives are dominating other South Asian countries. Sector-wise, residential sector contributed a maximum emission of 14.52 Ggyr-1 of N2O but is projected to reduce by more than 50% by 2041.This is because of successful promotion of cleaner fuels like liquified petroleum gas (LPG) over more polluting fuelwood. The power generation contributed 9.43 Gg yr-1of N2O emission, exhibiting maximum growth of 395%, followed by road transport (289%) and industry (231%). Future N2O emission from transport, power and industry are projected to rise by 2.8, 3.3. and 23.9 times of their 2017 estimates respectively due to the incapability of current policies to combat rising fossil fuel consumption. Mitigation options such as replacing diesel and compressed natural gas (CNG) vehicles with electricity driven vehicles can decelerate N2O emission to 45% by 2041 for road transport. A 41% reduction is possible by displacing coal with renewables in the power and industry sectors. Overall, the South Asian contribution to global N2O emission has enlarged from 2.7% in 1990 to 5.7% in 2007-2016, demanding an urgent need of N2O emission mitigation in the region.