Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Afrique du Sud → 2016 → Indigenous knowledge systems available to conserve soil and water and their effects on physico-chemical properties on selected smallholder farms of KwaZulu-Natal

University of KwaZulu-Natal (2016)

Indigenous knowledge systems available to conserve soil and water and their effects on physico-chemical properties on selected smallholder farms of KwaZulu-Natal

Chapoto, Rumbidzai Debra

Titre : Indigenous knowledge systems available to conserve soil and water and their effects on physico-chemical properties on selected smallholder farms of KwaZulu-Natal.

Auteur : Chapoto, Rumbidzai Debra.

Université de soutenance : University of KwaZulu-Natal

Grade : Doctor of Philosophy (PhD) 2016

Résumé partiel
Climate change and variability cause direct yield losses as a result of adverse environmental conditions and indirectly through losses resulting from insect pests attack. The impacts of a changing and variable climate are more likely acute in the developing countries as a result of poverty and economic challenges which limit the farmers’ capacity to adapt to risks associated with a changing and variable climate. Smallholder farmers in Zimbabwe are likely to face huge yield losses as a result of the changes in the abundance and distribution of insect pests. The aim of this study was to evaluate the responses of insect pests to a changing and variable climate in Zimbabwe. The study was conducted in the five agro ecological regions of Zimbabwe also known as natural regions to determine the perceptions of the farmers to climate change and its impact on insect pests, farmer knowledge and practices to manage insect pests of vegetable crops in a changing climate, map emerging insect pest distribution in Zimbabwe using climatic data as well as to model future distribution of emerging insect vectors. A participatory research approach using the survey questionnaires, interviews and focus group discussions was employed in the study. The Random Forest (RF) modelling algorithm was used to map the current and the projected distribution of the emerging insect vectors. Twenty two percent of the farmers across natural regions perceived changes in climate to be increases in temperatures throughout the year and an increase in the frequency of droughts. Late rainfall was cited by 16.4% of the farmers while long dry spells was cited by 16% of the respondents and 7.2% cited shorter cold season as the major indicator of a changing climate. Increasing incidence of heat waves, flash floods and the disappearance of wetlands and green spaces were cited as other indicators of a changing climate. Increased abundance of insect pests, decreased natural resource base and reduction in social safety nets were perceived to be the major climate change risks that were experienced by the smallholder farmers. The majority of the farmers (89%) have also expressed experiencing an increase in the incidence of insect pests such as aphids, stem borers, termites, diamond back moths, bollworms and whiteflies throughout the agro ecological regions of the country. Four percent perceived a decrease in insect pest incidence while 1% was not sure whether insect pests were increasing or decreasing. Farmers also perceived a change in behaviour of insects such as an increase in mobility as cited by 50.8%, and colour variations within insect species as highlighted by 73.6% and emergence of new insect pests which was highlighted by 59%. The perceived crop production risks as a result of the changes in climate included an increase in the abundance of insect pests such as aphids, stem borers, termites, diamond back moths, bollworms and whiteflies.

Présentation

Version intégrale (2,16 Mb)

Page publiée le 19 novembre 2018