| || || Maeke, Joseph|
| || || Vulnerability and impacts of climate change on food crops in raised atoll communities : a case study of Bellona community in Solomon Islands |
Institution: University of the South Pacific.
Award: M.Sc. Climate Change
Subject: Food crops -- Climatic factors -- Solomon Islands -- Bellona Islands, Climatic changes -- Environmental aspects -- Solomon Islands -- Bellona Islands, Crops and climate -- Solomon Islands -- Bellona Islands
Call No.: pac SB 176 .S6 M342 2013
Copyright:40-60% of this thesis may be copied without the authors written permission
Abstract: Climate change is a serious threat for Solomon Island communities’ food security. Therefore it is very important to understand the current vulnerability of Solomon Island communities’ food security to adverse impacts of climate change in order to develop important adaptation strategies to improve food security and reduce the impacts. This study examines the impacts of climate change and extreme events on food crop production in Bellonese communities in the Solomon Islands. Household interviews and surveys were conducted for 25% of households in four Bellona wards (West and East Ghonghau, Sa’aiho and Matangi) to collect and document information on food security systems and livelihood. The crop management information from the farmers were also used as inputs to calibrate and run the DSSAT (Decision Support System for Agrotechnology transfer) version 4.5 crop models to simulate the impacts of climate change (current, future) on taro (Colocasia esculenta), cassava (Manihot esculenta) and corn (Zea mays) growth and yield in three wards (West and East Ghonghau, Sa’aiho). Crop production impacts already observed in the four Bellonese wards included wilting, decline in crop yield, tuber/corm size, survival rate of young seedlings, crop growth, early or delay in maturity, abnormality of fruits/tubers, increase in pest and diseases, rotting, loss of some crop varieties, and loss of tuber flavor. Crop model projections for the three wards based on climate, atmospheric CO2, and soil type indicated that for Sa’aiho; C. esculenta yields are projected to decline by 12%, M. esculenta yields are projected to increase by 15.6%, and Z. mays yields are projected to decline by 13.2% for 2090. In both West and East Ghonghau, C. esculenta yields are projected to increase by 4.6% and 6.7% respectively, M. esculenta yields are projected to increase by 18.5%, and 24.1% respectively, and Z. mays are projected to decline by 8.3% for 2090. Based on crop model simulations of currently grown cultivars, C. esculenta cultivation will be restricted to the two fertile soil types, Kenge ungi and Kenge toaha found in West and East Ghonghau respectively. Z. mays yields are projected to decline. M. esculenta yields are projected to be the most resilient of the three crops, with sustained yields for all sites in all climate projections. The DSSAT crop model simulations also agreed with farmers reported impacts of El Niño induced drought of 1997. To improve food security in a changing climate in the studied sites, it is recommended for farmers to continue to implement their traditional iii sustainable cultivation and adaptation strategies which include; shifting cultivation, bush fallow practice, crop rotation, intercropping, diversification of crops, shade maintenance, mulching, planting fast yielding/resilient crops, adjust planting dates, increase number of plots, change planting sites, increase mound size, and planting distribution according to soil fertility and crop type. Furthermore, according to the crop models simulations farmers yield in Sa’aiho could be improved if they plant other C. esculenta cultivars; Bun long, Lehua, and Tausala-Samoa, with projected increased yields by 4.7-6.5 fold (3027-4209kg/ha) for 2090 and Z. mays cultivars; GL 482, PIO 3457 orig., WASH/GRAIN-1with projected increased yields by 3.9-4.4 fold (1040-1173kg/ha) for 2090. For West Ghonghau farmers yield could improve if they plant C. esculenta cultivars; Bun long, Lehua, and Tausala-Samoa, with projected increased yields by 2.3-3 fold (3574- 4972kg/ha) for 2090. Use of Z. mays cultivars, GL 482, PIO 3457 orig., WASH/GRAIN-1 with projected increased yields by 3.6-4.4 fold (962-1173kg/ha) for 2090. For East Ghonghau, farmers yield could improve if they plant C. esculenta cultivars, Bun long, Lehua, and Tausala-Samoa, with projected increased yields by 2-2.5 fold (3666-4681kg/ha) for 2090. Use of Z. mays cultivars, GL 482, PIO 3457 orig., WASH/GRAIN-1 with projected increased yields by 3.7-4.4 fold (965-1173kg/ha) for 2090. Overall, the study demonstrates the usefulness of crop modeling tools to assess the impacts of climate change on food crops in Bellona and to make actionable recommendations to increase food security and community resilience under a changing climate.