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Varshney R.K.,Indian International Crops Research Institute for the Semi Arid Tropics | Varshney R.K.,University of Western Australia | Bansal K.C.,Indian Agricultural Research Institute | Aggarwal P.K.,Indian Agricultural Research Institute | And 3 more authors.
Trends in Plant Science | Year: 2011

Developing crops that are better adapted to abiotic stresses is important for food production in many parts of the world today. Anticipated changes in climate and its variability, particularly extreme temperatures and changes in rainfall, are expected to make crop improvement even more crucial for food production. Here, we review two key biotechnology approaches, molecular breeding and genetic engineering, and their integration with conventional breeding to develop crops that are more tolerant of abiotic stresses. In addition to a multidisciplinary approach, we also examine some constraints that need to be overcome to realize the full potential of agricultural biotechnology for sustainable crop production to meet the demands of a projected world population of nine billion in 2050. © 2011 Elsevier Ltd. Source

Mekuria W.,International Water Management Institute IWMI | Aynekulu E.,International Center for Research in Agroforestry | Aynekulu E.,Mekelle University
Land Degradation and Development | Year: 2013

In the northern highlands of Ethiopia, establishment of exclosures to restore degraded communal grazing lands has been practiced for the past three decades. However, empirical data on the effectiveness of exclosures in restoring degraded soils are lacking. We investigated the influence of exclosure age on degree of restoration of degraded soil and identified easily measurable biophysical and management-related factors that can be used to predict soil nutrient restoration. We selected replicated (n=3) 5-, 10-, 15-, and 20-year-old exclosures and paired each exclosure with samples from adjacent communal grazing lands. All exclosures showed higher total soil nitrogen (N), available phosphorus (P), and cation exchange capacity than the communal grazing lands. The differences varied between 2·4 (±0·61) and 6·9 (±1·85) Mgha-1 for the total N stock and from 17 (±3) to 39 (±7) kgha-1 for the available P stock. The differences in N and P increased with exclosure age. In exclosures, much of the variability in soil N (R2=0·64) and P (R2=0·71) stocks were explained by a combination of annual average precipitation, woody biomass, and exclosure age. Precipitation and vegetation canopy cover also explained much of the variability in soil N (R2=0·74) and P (R2=0·52) stocks in communal grazing lands. Converting degraded communal grazing lands into exclosures is a viable option to restore degraded soils. Our results also confirm that the possibility to predict the changes in soil nutrient content after exclosure establishment using regression models is based on field measurements. © 2011 John Wiley & Sons, Ltd. Source

Alauddin M.,University of Queensland | Sharma B.R.,International Water Management Institute IWMI
Ecological Economics | Year: 2013

While the bulk of research on crop water productivity (WP) focuses on static cross-section analysis, this research provides a spatio-temporal perspective. It estimates rice crop WP for 21 Bangladesh districts for 37. years; explores WP variations among districts; and investigates causality involving WP, intensification and technological variables; and groundwater irrigation and depth. It breaks new grounds by probing these significant but unexplored issues.Technological diffusion was the key factor explaining inter-district WP differences. The impact of agricultural intensification on rabi (dry season) and kharif (wet season) crop WPs was positive and negative respectively. Dummy variables typifying policy transition negatively impacted on WPs for both kharif and overall crops. While rabi and kharif rice WPs grew with time, overall crop WP recorded the strongest growth. Rabi and overall WPs were lower in salinity- and drought-prone districts covering 33% of Bangladesh's net cropped area (NCA).In 90% of Bangladesh's NCA districts, technological diffusion caused WP. Causality existed between groundwater irrigation and depth in 60% NCA. Despite significant potential to increase WP, increasing dependence on groundwater appears unsustainable. Widespread diffusion of HYVs in the kharif season, and development of salinity and drought-tolerant rice varieties could go a long way in sustaining rice WP. © 2013 Elsevier B.V. Source

Katic P.,International Water Management Institute IWMI | Quentin Grafton R.,Australian National University
Journal of Hydrology | Year: 2011

This paper evaluates the trade-off between resilience and economic payoffs in terms of groundwater extraction where there is a risk of an irreversible and catastrophic event. A dynamic and spatial model is developed that incorporates a stochastic recharge process and the risk of an irreversible catastrophic event (such as saltwater intrusion) that arises when hydraulic heads fall below a given threshold. The results show that if the threshold is uncertain then controlling both the rate and depth of extraction can generate a higher economic return and a lower probability of crossing the threshold than only controlling the rate of extraction. This occurs even if the extraction rate is set optimally and is less than the extraction rate than when two forms of control are used. The model and findings provide an applied framework to understand and to quantify where there might be 'win-win' outcomes, and trade-offs between economic payoffs and resilience in terms of groundwater extraction. © 2011 Elsevier B.V. Source

Yakubov M.,International Water Management Institute IWMI
Irrigation and Drainage | Year: 2012

Irrigation performance assessments are important tools that irrigation service providers at various levels of the water management hierarchy can use for monitoring, benchmarking and self-improvement. Despite the recognition that irrigation performance can and should be assessed from a variety of perspectives, the perspectives of the users, farmers, have received surprising little attention. This is even more apparent given the widespread context of irrigation management transfer reforms throughout the world aiming at effective user empowerment through farmer-owned and driven water users associations. This paper attempts to partially fill this gap by exploring and sensitizing farmers' views about irrigation service and related performance dimensions using qualitative research methods. Based on focus group discussions with a purposive sample of farmers from a range of water users' associations in Central Asia and a grounded theory approach the study lays a conceptual foundation for future practical applications. © 2011 John Wiley & Sons, Ltd. Source

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