| || || Root crops -- Climatic changes -- Solomon Islands -- Santa Isabel -- Case studies|
| || || Assessing the ecological impacts of climate change on root crop production in high islands : a case study in Santa Isabel, Solomon Islands|
Author: Quity, Gareth
Institution: University of the South Pacific.
Subject: Root crops -- Climatic changes -- Solomon Islands -- Santa Isabel -- Case studies , Root crops -- Solomon Islands -- Santa Isabel -- Case studies
Call No.: pac SB 210 .S6 Q59 2012
Copyright:20-40% of this thesis may be copied without the authors written permission
Abstract: Farmers and community perceptions on the ecological impact of climate variability and change on root crop growth and yield were assessed in six villages namely; Hovikoilo, Guguha, Tatamba, Ligara, Biluro and Hirolegu on Isabel Island in Solomon Islands. The root crops included sweet potato (Ipomoea batatas), cassava (Manihot esculenta), taro (Colocasia esculenta) and yam (Dioscorea alata) and were evaluated using farmers knowledge on the following ecological variables: i) range shifts, ii) crop growth and health, and iii) crop yield. Assessment and evaluation conducted through use of questionnaires, face-to-face interviews, site visits and observation. The second part of the study involved use of Decision Support System for Agro technology Transfer (DSSAT) computer modeling software to simulate root crop growth and yield with the changing climate. The study showed that farmers and village communities experienced changes in temperature and rainfall patterns. According to PCCSP (2011), the max temperature for Solomon Islands had increased at a rate of 0.15oC per decade since 1951 and projected to be between 0.4 – 1.0oC in 2030 under high emission scenarios. Rainfall showed substantial variation from year to year. However, annual and seasonal projection of rainfall also projected increased rainfall patterns and extreme rainfall days. These changes triggered droughts, cyclones and flooding. Farmers are also concerned about increased runoffs and soil erosion, loss of soil fertility and nutrient loss which have direct and indirect effect on root and tuber crop growth and yield. The DSSAT model output provided relevant information on crop growth and yield, and the limiting factors that associated with the phenological and physiological processes of crops. In this study, two taro cultivars; Tausala Samoa and Lehua were simulated on three sites (Hovikoilo, Biluro and Tatamba). The results showed that the growth of Tausala Samoa variety was susceptible in all three sites to nitrogen leaching caused by runoff due to heavy rainfall, and yield is fairly low. While Lehua variety is more resistant to nitrogen leaching and runoffs and produced high yield. The yield projections were also made for both cultivars in years 2030, 2055 and 2090 using the PCCSP future climate projections.