In the ancient past, agriculture was central to the daily routines of life and economic organisation. The major limiting factor on crop production in dry regions, such as Western Asia, is the availability of water. In these regions. rainfed crops are susceptible to drought-induced failure and, while farmers can water their crops artificially, this places demands on labour and water supplies. The effort and resources afforded to crops by farmers can indicate the scale of production. whereas the preferential treatment of certain crops over others offers insights into the cultural and economic role of different crops. There are a variety of methods by which crop water status can be inferred from archaeological evidence. One such method is stable carbon isotope analysis of charred crop remains, which are ubiquitous at archaeological sites in dry regions. This thesis assesses the utility of stable carbon isotope analysis as a means of inferring crop water status. Experiments were conducted to establish the relationship between isotopic ratios and water status in modern crops grown in known conditions. Laboratory tests were also undertaken to determine the extent to which isotopic ratios may be altered post-mortem. In light of the findings from these experiments, isotopic analysis was carried out on crop remains from nine archaeological sites, primarily located in Western Asia and of Neolithic and Bronze Age date. Natural variation. unknown differences in growing conditions and plant physiology, and small post- mortem alterations, limit the precision with which crop water status can be inferred from stable carbon isotope ratios. Nevertheless, stable carbon isotope analysis can provide a reliable indication of the water status of ancient crops. On this basis. it is possible to develop interpretations regarding agricultural arrangements at individual sites, and to identify regional trends in ancient crop production.

Der Bericht gibt einen Überblick über den Umfang der bewässerten landwirtschaftlichen Fläche in Sachsen und die bewässerten Kulturarten. Verschiedene Bewässerungsverfahren und -techniken sowie Steuerungsmodelle werden vorgestellt und bewertet. Weiterhin sind die Ergebnisse von Wirtschaftlichkeitsuntersuchungen dargestellt. Die Bewässerungsfläche in der sächsischen Landwirtschaft entspricht nur 0,4 % der landwirtschaftlichen Nutzfläche, zeigt aber auf Grund verstärkter Frühsommertrockenheit eine steigende Tendenz. Gemüse, Obst und Kartoffeln sind die am häufigsten bewässerten Kulturarten. Mobile Beregnungsmaschinen (Schlauchtrommeln) mit Großregnern dominieren, Kreis– und Linearberegnungsmaschinen sind allerdings umwelt– und ressourcenschonender. Für die Optimierung hinsichtlich Wasserverbrauch und Wirtschaftlichkeit stehen Softwarelösungen und Beratungsdienste zur Verfügung. Die Bewässerung ist bei gezielter Steuerung und bei beregnungswürdigen Fruchtarten meist wirtschaftlich.

Thesis (M.Dev.) --University of Limpopo, 2011 / Agricultural development programs under the former apartheid homeland system which was dissolved in 1994 could not successfully achieve their objectives. The current democratic government reviewed the policies and programs put in place during apartheid era which eventually led to the implementation of the Revitalisation of Smallholder irrigation Schemes (RESIS) in line with the Reconstruction and Development Program (RDP) and Growth, Employment and Redistribution (GEAR) programs. It was anticipated that RESIS would among others improve agricultural productivity, play a role in local economic development, improve food security, provide improved benefits and the livelihoods of the rural communities where the schemes are situated. The aim of the study is to assess whether the RESIS program has had an impact so as to make recommendations for future similar programs. The objective of the study is to assess the impact of RESIS program on the livelihoods of the participants and to shed light on whether such programs can be used for poverty reduction, which is a key objective in the programs of LDA. Tšwelopele irrigation scheme in Greater Tubatse Municipality within Sekhukhune District Municipality was selected as the area at which the study was conducted. A random sample of 50 beneficiaries was selected from a total of 75 RESIS beneficiaries and divided into two strata, namely, full-time farmers (both male and female) and part-time farmers (male and female) farmers. Interviews were conducted through completion of questionnaires responded to by the selected participants and key informants in the scheme. Qualitative and quantitative methods were used to obtain the responses from the scheme participants and the data processed using SPSS. Based on the analysis of respondents‟ perceptions of the farmers, the study concludes that RESIS is perceived to have had a positive impact on the livelihoods of the beneficiaries. Gross margin analysis supports the farmers‟ perceptions.

A typical irrigation scheduling problem is one of preparing a schedule to service a group of outlets. These outlets may either be serviced sequentially or simultaneously. This problem has an analogy with the classical earliness/tardiness machine scheduling problems in operations research (OR). In previous published work integer programme were used to solve such problems; however, such scheduling problems belong to a class of combinatorial problems known to be computationally demanding (NP-hard). This is widely reported in OR. Hence integer programme can only be used to solve relatively small problems usually in a research environment where considerable computational resources and time can be allocated to solve a single schedule. For practical applications meta-heuristics such as genetic algorithms, simulated annealing or tabu search methods need to be used. However as reported in the literature, these need to be formulated carefully and tested thoroughly. This thesis demonstrates how arranged-demand irrigation scheduling problems can be correctly formulated and solved using genetic algorithms (GA). By interpreting arrangeddemand irrigation scheduling problems as single or multi-machine scheduling problems, the wealth of information accumulated over decades in OR is capitalized on. The objective is to schedule irrigation supplies as close as possible to the requested supply time of the farmers to provide a better level of service. This is in line with the concept of Service Oriented Management (SOM), described as the central goal of irrigation modernization in recent literature. This thesis also emphasizes the importance of rigorous evaluation of heuristics such as GA. First, a series of single machine models is presented that models the warabandi (rotation) type of irrigation distribution systems, where farmers are supplied water sequentially. Next, the multimachine models are presented which model the irrigation water distribution systems where several farmers may be supplied water simultaneously. Two types of multimachine models are defined. The simple multimachine models where all the farmers are supplied with identical discharges and the complex multimachine models where the farmers are allowed to demand different discharges. Two different approaches i.e. the stream tube approach and the time block approach are used to develop the multimachine models. These approaches are evaluated and compared to determine the suitability of either for the irrigation scheduling problems, which is one of the significant contributions of this thesis. The multimachine models are further enhanced by incorporating travel times which is an important part of the surface irrigation canal system and need to be taken into account when determining irrigation schedules. The models presented in this thesis are unique in many aspects. The potential of GA for a wide range of irrigation scheduling problems under arranged demand irrigation system is fully explored through a series of computational experiments.

Der Bericht gibt die Ergebnisse 5-jähriger Bewässerungsversuche mit Markerbsen, Buschbohnen, Speisezwiebeln, Spinat und Weißkohl wieder. Dabei kamen u. a. ‘trockenstresstolerante‘ Sorten zum Einsatz, die aber keine Vorteile zeigten. Das angewendete Verfahren zur Bewässerungssteuerung führte zu überhöhten Wassergaben. Es kann damit für die untersuchten Kulturen, mit Ausnahme der Buschbohne, nicht als ressourcenschonendes Verfahren für den mitteldeutschen Anbau empfohlen werden. Der Bericht wendet sich an Praktiker und Berater, die sich intensiv mit dem Thema Bewässerungssteuerung beschäftigen.

Thesis (M.Sc. (Agriculture)) -- University of Limpopo, 2014 / The study was designed to establish the impact of irrigation schemes on job creation and also from the jobs created to differentiate permanent from temporary jobs. The focus of the study was on three smallholder irrigation schemes (Mabunda, Mariveni and Seloane, the irrigation schemes are located in Greater Giyani, Greater Tzaneen and Ba- Phalaborwa municipalities respectively). For the purpose of the study, Mabunda will be addressed as scheme 1, Mariveni as Scheme 2 and Seloane will be addressed as Scheme 3.The main crops cultivated in the three irrigation schemes are citrus, coupled with vegetables to generate funds when citrus is out of season. The study employed a case study approach and used both qualitative and quantitative methods to collect data. The study was implemented in two phases: the first phase focused on irrigation scheme participants, while the second phase focused on the community structures (livestock committee, youth, water committee and tribal council) that have been affected by the establishment of the irrigation schemes. Data was collected from the irrigation schemes beneficiaries and community structures by means of a structured questionnaire. No random selection method was used in the selection of irrigation scheme beneficiaries. This was influenced by the small number of beneficiaries in the three schemes (56).It was only the community structures that were randomly selected. One hundred and five (105) people were interviewed representing different structures in all three villages. Out of this figure thirty five(35) people were interviewed per village. Data collected was organized into themes for analysis. Data was analyzed manually, where the coded questionnaires were recorded into a spread sheet. The process of analysis was carried out by using qualitative description and descriptive statistics. Data was manually analysed and the output was discussed using tabulation and cross-tabulation of variables with percentages in descriptive statistics. From the spread sheet data was summarized manually. For the period 2006 to 2009, the irrigation schemes anticipated to create 42 permanent job opportunities with the exception of 2006 where the projected jobs were 32. For the same period, the following temporary job opportunities were anticipated: 121 in 2006,236 in 2008, 240 in 2010, 234 in 2012,233 in 2014 and 232 in 2016. The irrigation schemes also anticipated to inject the monetary value into the community in the form of basic salaries. In 2006, R839,996.76 was injected into the community in the form of salaries, 2008 – R1,509,060.33, 2010 – R1,775,531.58,from 2012 – 2018. R2,045,130.36, R2,381,396.14 and R2,772,145.45 injected into the community respectively, while the divisional management team were expected to receive, R27,525, R36,800, R35,920, R43,857 and R54,118 in the form of performance bonuses, in 2008, 2010, 2012, 2014 and 2016 respectively. The actual permanent jobs created for the period 2005 to 2009 in Scheme 1, an average of 64.6 (the anticipated was 42), while the actual temporary jobs created averaged 395. Scheme 2, managed to create an average of 86 permanent jobs and 197 temporary jobs, while the anticipated was 42 and 240 respectively. In Scheme 3, averages of 74 permanent jobs were created while 55.4 temporary jobs were created. The irrigation schemes created more jobs than anticipated. This was influenced by the high rate of unemployment in the villages located next to the irrigation schemes and the irrigation schemes as the only job providers closer to the villages. Temporary workers are paid performance based salaries. For the period 2005 to 2009, they were paid as follows: in 2005, they were paid R0.35 per bag of oranges harvested. The actual salary earned per month was informed by the number of bags harvested for that particular month. The following years the salary was increased by five cent per bag. Permanent workers were paid an average salary of R2400.00 per month. The study recommended that the roads leading to the three irrigation schemes should be maintained to minimize fruit damage during transportation to the market. The schemes should also be financially assisted to acquire own farm equipment (tractors, trailers and trucks) and be trained on the maintenance of these equipment to reduce acquiring services from the private service providers. The three irrigation schemes use private transport to carry their produce to the market and they are charged for this service, hence, the acquisition of own transport is necessary.

Der Bericht gibt einen Überblick über den Umfang der bewässerten landwirtschaftlichen Fläche in Sachsen und die bewässerten Kulturarten. Verschiedene Bewässerungsverfahren und -techniken sowie Steuerungsmodelle werden vorgestellt und bewertet. Weiterhin sind die Ergebnisse von Wirtschaftlichkeitsuntersuchungen dargestellt. Die Bewässerungsfläche in der sächsischen Landwirtschaft entspricht nur 0,4 % der landwirtschaftlichen Nutzfläche, zeigt aber auf Grund verstärkter Frühsommertrockenheit eine steigende Tendenz. Gemüse, Obst und Kartoffeln sind die am häufigsten bewässerten Kulturarten. Mobile Beregnungsmaschinen (Schlauchtrommeln) mit Großregnern dominieren, Kreis– und Linearberegnungsmaschinen sind allerdings umwelt– und ressourcenschonender. Für die Optimierung hinsichtlich Wasserverbrauch und Wirtschaftlichkeit stehen Softwarelösungen und Beratungsdienste zur Verfügung. Die Bewässerung ist bei gezielter Steuerung und bei beregnungswürdigen Fruchtarten meist wirtschaftlich.

This study’s main goal was to evaluate Bacillus subtilis inoculation and mine water irrigation effect on germination, growth, nodulation, physiology and shoot/grain quality of cowpea genotypes exposed to extreme climatic conditions (elevated temperatures). The first experiment evaluated the interactive effect of Bacillus subtilis (BD233) inoculation and elevated temperature on germination indices and plumule lengths of three genotypes (Asetanapa, Soronko and Nyira) of cowpea. The results showed that interaction between B. subtilis (BD233) and temperature significantly (p<0.05) influenced the germination indices (germination percentage (G%), germination index (GI) and germination rate index (GRI)) and plumule length of cowpea seedlings and genotype responses were significantly different. At elevated temperature (35oC), inoculation with B. subtilis (BD233) enhanced seed germination and growth of cowpea. The second experiment evaluated the effect of temperature on growth and nutritional content of cowpea incubated for seven days in a growth chamber. The results showed that when cowpea genotype, Soronko, was incubated at different temperature regimes, the whole plant biomass, shoot carbon and crude protein contents were significantly affected with temperature increases at all three stages of the plants’ life cycle. The results suggest that the pre-flowering (40 DAP) and flowering (90 DAP) stages of cowpea compared to post-flowering (123 DAP) are more susceptible to elevated temperatures (30-35oC). The third experiment evaluated Bacillus subtilis inoculation and mine water irrigation effect on growth, nodulation, physiology and nutritional content of cowpea under glasshouse conditions. The results revealed that the interaction of B. subtilis (BD233) inoculation and mine water (75% AMD) irrigation was significant for the growth, nodulation, stomatal conductance, chlorophyll contents and shoot/grain nutritional quality of cowpea genotypes. In comparison with control, generally, B. subtilis inoculation enhanced the growth, nodulation and yield of all tested cowpea genotypes and irrigation with mine water significantly influenced the mineral contents in both shoot and grain of cowpea. Taken together, findings in this study have implications for cultivation of cowpea, an important candidate for food/nutrition security in Africa, under future climate change scenarios. / Environmental Sciences / M. Sc. (Environmental Sciences)