A bird's eye-view of smallholder productivity : Current measurement shortfalls, farmer perceptions and rationality on rainfed family farms in Ghana

Smallholder farming, which is largely rainfed and relies on mostly rudimentary tools, predominates Ghana’s agricultural sector. The sector’s importance to the national economy is exemplified in not only the proportion of the active national labour force engaged in it but also in terms of its export earnings and service as a source of food for the vast majority of the population. However, the sectors is also plagued with historically low productivity. Statistics from the country’s national statistical service shows that while more than six tons per hectare is achievable for maize, what farmers actually obtain from their plots is less than a third of this. Being the most important staple crop and given the continuously increasing population growth rate, these low yield levels are most worrying. This is particularly so if the agriculture sector is expected to play the historically important role of being the engine of economic growth for the national economy as it has been for other countries.Through this thesis, I aim to augment our present understanding of crop productivity levels on smallholder family farms. I do this by showing the limitations of current methods of yield measurement, analysing the factors contributing to current yield levels and variability, as well as analysing farmers’ perspectives on their current productivity levels. Using a multidisciplinary framework, I employ a mixed methods approach to analyse data from field and household surveys as well as aerial photographs and photo-elicitation interviews. For inspiration, I also draw on a number of theories; Boserup’s theory on agricultural intensification in the face of population growth and Chayanov’s theory of the smallholder economy help provide the frame for the thesis. The more practical induced innovation model of agricultural development and the sustainable livelihood approach help provide the bridge to the empirical work.The thesis comprises four articles, which are preceded by a kappa. I argue that current measurement approaches do not adequately capture the dynamism of smallholder farms and that the use of new remote sensing tools as employed in this work could be critical to improving the reliability of agricultural statistics in such complex farming systems. I also argue that the factors contributing to current yield levels are varied and inconsistent across yield measures and villages even in the same agroecological regions. I further argue that while management activities such as the timing of planting and quantity of fertilizer applied are important immediate determinants of yield levels, they are often underpinned by some socioeconomic factors relating to labour and land tenure dynamics. The thesis further establishes that, by and large, farmers are content with current productivity levels and this attitude is rationally based on their experience and knowledge of poorly functioning agricultural inputs and outputs market. These findings have significant implications for the future of these small farms in terms of their own survival as well as their ability to continue to play critical roles in the economies of developing countries in Sub-Saharan Africa

Time series analysis of high resolution remote sensing data to assess degradation of vegetation cover of the island of Socotra (Yemen)

The island of Socotra has long been in geographical isolation, hence nearly 30% of the plant species are believed to be endemic to the island. Until the end of 20th century there was only very little and incomplete information and literature about the vegetation on the island. This isolation broke down in 1990 with the country unification in which then the island received much attention. Subsequently the scientific knowledge of the local flora slowly increased, but many of plant species are now reported to be confined into small populations, hence being particularly vulnerable to habitat loss, overgrazing, as well as urban expansion. 1. The overall objective of this research attempted to assess and examine the trends of vegetation changes since 1972 to 2010 with the use of Landsat MSS, TM and ETM+ images and to investigate the related driving factors, such as rainfall, grazing pressure changes and underlying spatial variability of the landscape. This is to answer the overall question: Is there a trend in biomass, cover and species composition on Socotra Island over the last 40 years? If so, is that trend associated with the rainfall patterns? What are the drivers behind the vegetation change? And then how can we define changes in patterns or changes in this study area? 2. From a methodological point of view, our approach of systematically using remote sensing technology data proved scientifically an applicable tool to improve our understanding of the spatial complexity and heterogeneity of the vegetation cover as well as to provide a conceptual method with specific data for monitoring the changes over this time period. Our data obtained from these different Landsat sensors during the study period were - after many sophisticated processing steps - essentially able to provide time series information for Normalized Difference Vegetation Index (NDVI) data and to assess the long term trend in vegetation cover in the island. 3. Moreover, our approach combining supervised maximum-likelihood and unsupervised classification with the pre- and the post-classification approaches besides the knowledge based classification was table to provide sufficient results to distinguish and to map nine (9) terrestrial vegetation cover classes. The overall accuracy (compared with ground truth data) was about 91%, 77%, 70% and 72% for the images 2005, 1994, 1984 and 1972 respectively. Consecutively, the GIS analysis allowed estimates of highly valuable information as absolute areas and relative coverage of particular vegetation classes over the island with their spatial distribution and also their ecological requirements. Analysis of climatic conditions and NDVI 4. As a results of the complex topography of the study area and the wide climate range, with the guidance of prior knowledge of functional relationships between site parameters, ecosystem and the specific form of biological production, our work resulted in a division of the entire area into six variously sized ecosystem units, which were enough to properly depict the spatial heterogeneity of the rainfall and vegetation and to assist reflecting the influence and reaction between environmental parameters as well as it might have significance both for development of resources and for conservation of environment