Achieving food security and sustainability in a changing climate: assessing the performance of smallholder rice-based cropping systems in southern Bangladesh

Emran, Shah-Al

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Description

Title

Achieving food security and sustainability in a changing climate: assessing the performance of smallholder rice-based cropping systems in southern Bangladesh

Author(s)

Emran, Shah-Al

Issue Date

2021-07-12

Director of Research (if dissertation) or Advisor (if thesis)

Bollero, Germán A.

Doctoral Committee Chair(s)

Pittelkow, Cameron M.

Committee Member(s)

• Lee, DoKyoung
• Michelson, Hope C.

Department of Study

Crop Sciences

Discipline

Crop Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Date of Ingest

2022-01-12T22:55:01Z

Keyword(s)

• Food security
• Poverty
• Multi-criteria performance
• Sustainability
• Nitrogen use efficiency
• Energy productivity
• Greenhouse gas
• Cropping system diversity

Abstract

Globally, approximately 475 million smallholders face key challenges to achieving food security and no poverty goals while maintaining environmental sustainability. The global demand for food and non-food agricultural products will increase at least 60% between 2010-2050, while smallholders are facing a range of socioeconomic and biophysical constraints at the farm-level with increasing threats from climate change and extreme weather events. This is particularly true for smallholder households in coastal Bangladesh, where rice-based cropping systems are characterized by low annual productivity and suboptimal management, but efforts to increase food production and economic profitability may have negative consequences for carbon footprint, nutrients, energy, and labor resource use efficiencies. Hence, to design more effective agricultural development and extension policies for achieving sustainable food security, it is critical for research to consider a multi-disciplinary approach. With the overall goal of identifying promising leverage points for sustainable development in coastal Bangladesh, the objectives of this Ph.D. research were to a) conduct an integrated assessment of variables related to socioeconomic status, farm characteristics, and crop management practices to understand the major factors influencing crop productivity, b) evaluate the impact of cropping system intensification and diversification options on farm-level multi-criteria performance and explore the scope to close gaps in food production and resource use efficiencies among smallholder households, and c) evaluate the effects of nitrogen (N) rate and source on the agronomic, economic, and environmental performance of transplanted and rainfed aman (monsoon-season) rice in Bangladesh's non-saline coastal areas. The first two objectives were addressed by using a panel survey dataset consisting of 32 variables from 502 farm households located within polder (coastal embankment) and outside polder systems. The third objective was addressed by conducting 51 on-farm experiments in the highland and medium highland landscape positions. In Chapter 1, Smallholders' household variables were characterized by five independent latent factors named Farming Challenges, Economic Status, Crop Management Practices, Asset Endowment, and Farm Characteristics through factor analysis. Asset Endowment and Crop Management Practices were identified as the most important factors for increasing crop productivity on a household and per unit area basis, respectively. Despite the importance of these factors, changes in household off-farm income played the strongest role in improving economic livelihoods in this coastal area. In Chapter 2, we observed that agricultural intensification can increase rice equivalent yield up to 213.71 and 183.8 % compared to a single annual rice crop within and outside polders, respectively. However, intensification with two rice crops showed large tradeoffs in carbon footprint and resource use efficiencies. Meanwhile, cropping system diversification options, particularly including legumes in rotation with rice (mung bean, lathyrus, and groundnut), led to a win-win situation by enhancing the multi-criteria performance index (MCPI) while reducing environmental tradeoffs, owing to higher nitrogen use efficiency, potassium use efficiency, and profitability with a reduced carbon footprint. In chapter 3, agronomic nitrogen use efficiency varied with changes in the combination of N rates and source (broadcast prilled urea or deep-placed urea super granules (USG)) at different landscape positions and rice variety. Traditional rice grown on medium-highlands was found to require 28 kg N ha−1 to maintain yields and profitability while limiting tradeoffs in agronomic nitrogen use efficiency and environmental externalities. In highland locations, clear trade-offs between agronomic and environmental goals were observed. These findings suggest that farmers can consider the use of USG at 50 kg N ha−1 to produce yields equivalent to 75 kg N ha−1 of prilled urea in highland landscapes while also reducing environmental externalities. These findings demonstrate that agricultural intensification options exist for boosting farm-level crop productivity in these low-input, rice-based systems, including both increased use of inputs (nutrients and energy) as well as higher cropping intensity. Yet, in order to meet sustainable intensification goals for smallholders, cropping system diversification with legumes should be a priority to minimize tradeoffs with carbon footprint and labor, nutrient, and energy use efficiencies compared to two annual rice crops. Given the critical importance of nutrient management for enhancing rice productivity in South Asia's coastal zones, our results suggest N requirements should be evaluated within specific production contexts (e.g., cultivar type within landscape position) to identify options for increasing yields without negatively influencing environmental and economic indicators. The multi-criteria approach taken in this research highlights new opportunities for agricultural development, which could help policy-makers prioritize investments to improve food security while also considering income generation and environmental sustainability outcomes for smallholder households in coastal areas of Southern Bangladesh.

Graduation Semester

2021-08

Type of Resource

Thesis

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Copyright 2021 Shah-Al Emran

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