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This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

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Improved hybrid genetics and more efficient farming techniques have increased corn (Zea mays L.) production and grain yields for Mid-South farmers. Early planting is one technique to mitigate heat and drought stress that negatively influence grain production. The first objective was: a) determine the effect of early planting on grain yield, b) to determine the effects on physiological characteristics and c) determine if some hybrids are better suited for early planting. Data suggest there were yield advantages for early planted treatments. Starkville 2014 yields exhibited the greatest reduction of .80 Mg ha-1 for each week that planting was delayed. A second objective was: a) determine optimum plant density when planting early, b) determine population effects on physiological characteristics, and c) determine hybrid responses. Hybrids were evaluated at seeding rates ranging from 49,400 to 98,800 plants ha-1. Corn grain yield was maximized at 86, 450 to 98,800 plants ha-1.

The Sufri variety of date is widely cultivated in Saudi Arabia, where it 'produced large quantities of dates. The high quality dates are consumed fresh, dried or preserved, the surplus and second quality dates may be damaged by improper harvesting, handling, transporting and processing. The Sufri variety of date is one of moderate quality and there is a surplus in local markets for processing into overflows to be used as "a base" for the food industry. The present work was conducted to increase soluble solids, including sugars, in the overflows and to maintain the quality of the underflows; chemical analysis of both the overflows and the underflows revealed that Sufri date contains proteins/ amino acids and pectin in small quantities, which can be utilised as byproducts. Physical treatment involved maceration with different ratios (date/water) at mild temperatures (30-60°C) for different times (10- 30 min). Over this range the increase in soluble solids in the overflow was at a minimum but the underflow retained its quality and softening of date tissues was achieved. Different extraction ratios indicated that a lower ratio produced a low overflow which was turbid, but that the higher ratios produced overflows which were dilute. Serial extractions with the same ratio in the initial extraction was not practical. In enzymic treatment, pectolytic enzymes were incubated with date underflows at different concentrations, temperatures for various incubation times. Overflows increased significantly over a short time and at low temperatures (30 min and 30°C) indicating the effectiveness of pectolytic enzymes in releasing more of the overflows, and sugars were increased in the overflows as an indication of the effect of these enzymes on date cell walls. Pure pectolytic enzymes were investigated and it was found that specificity was very important for selection of suitable pectolytic enzymes. It is concluded that the Sufri variety of date is a good source of reducing sugars, and its by-products have a promising future.

Thesis (MComm)—Stellenbosch University, 2015. / ENGLISH ABSTRACT: The second step in the study was to empirically measure the competitive performance of the date industry based on this trade orientation, using the relative trade advantage (RTA) method. Trade data from FAOSTAT and Trademap were used. Since 2001, the Namibian date industry has consistently recorded positive trends with RTA values ranging between 0.40 and 4.0. When compared to other international competitors, the results indicate that Tunisia is by far the most competitive country, with RTA values ranging between 278 and 391. Namibia’s date industry leads competitors such as South Africa, the USA, Kenya, Australia and India. In step 3, an industry-wide survey was conducted among executive-level industry role players, which identified 72 factors influencing competitive performance. The 72 factors were rated and analysed through chi-square and one-way analysis of variance (ANOVA) in terms of their current impact as enhancing or constraining and also in terms of their relevance to the industry. The results revealed that all factors were rated highly relevant (i.e. important) to the industry’s competitive performance levels, with 47 percent playing an enhancing role, while 43 percent were constraining competitive performance in the Namibian date industry. Differences between views on the current impact and long-term relevance of factors provided a ‘performance gap’ that the industry had to attend to strategically in order to improve competitive performance. The top three most enhancing factors are the substantial size of the international date market, the availability of unskilled labour, and the suitability of Namibian date production (project) locations. The highest rated constraining factors were identified as: the lack of privately funded scientific research capacity, the slow growth and small size of local markets, and insufficient industry expenditure on research and development (R&D). The fourth step applied Porter’s theory of competitiveness (1990; 1998) to derive the industry determinants of competitive performance. The 72 factors were grouped into the six Porter diamond determinants. Principal component analysis (PCA) was undertaken to identify variations and consensus in the views of respondents with respect to the relevance and impact of factors identified for each determinant. The results revealed that there were variations in opinions with regard to 52 factors and consensus on 20 factors, influencing the industry’s competitive performance. In analysing opinions on the impacts and long-term relevance of the identified factors, two value chain clusters were identified, viz. those opinions or respondents directly involved in the production processes of dates (cluster 1); and those providing supporting functions to the production process (cluster 2). The results indicate that although there are similarities in the opinions within the date industry value chain, important differences do exist and must be noted in strategic planning process by the industry. Differences were recorded with regard to access to quality technology, obtaining long-term credit, diversification in the international market, cost of specialised technology services, the effect of legal and political factors on the industry’s strategic position, the country’s black economic empowerment (BEE) policy and health cost implications. In step 5, the most important findings from steps 3 and 4, together with views gathered from a date industry information session (the DIS) and personal interviews, were included in a strategic decision matrix aimed to develop industry-level proposals to improve competitive performance. This matrix listed constraining factors for which a large degree of industry-level consensus was recorded, together with those actions that could improve performance immediately. Proposals highlighted were: focusing on human resources and skills development; cost-sharing activities; public-private partnerships in the development of project-level socio-economic investment packages, investing in long-term research and development (R&D); upgrading export facilities; local market development and improved collaboration with national retailers; reduction of marketing costs; export-market diversification; developing representative industry-level institutions and an industry-level strategic plan; and mobilising government-level support more effectively in order to create a conducive environment for the industry to compete successfully. / AFRIKAANSE OPSOMMING: Hierdie studie het die mededingende prestasie van die Namibiese dadelbedryf vanaf 2001 tot 2013 ondersoek. In die studie is die konvensionele raamwerk vir die mededingendheidsanalise van agribesigheid (verwys na Ismea, 1999; Esterhuizen, 2006; Van Rooyen et al., 2011; Boonzaaier, 2014; Jafta, 2014) verfyn om die geldigheid van die vrae wat die respondente geantwoord het en die verskille in hulle response teenoor huidige impakte en langtermyn relevansie te oorweeg. Opinies vanuit die waardeketting van die dadelbedryf is ook ingesluit in die ontledings. Die konsep van mededingendheid is eerstens gedefinieer, gebaseer op die belangrikheid van internasionale handel vir die Namibiese dadelbedryf, as die vermoë van die dadelbedryf om sy produkte op ’n volhoubare basis in beide binnelandse en internasionale markte te verhandel en, as sulks, te kan voortgaan om skaars hulpbronne soos grond, arbeid, tegnologie, bestuurstalente en kapitaal te lok en terselfdertyd ten minste die geleentheidskoste van opbrengste op hulpbronne verbruik, te verdien (aangepas uit die werk van Freebairn, 1986; Esterhuizen, 2006; Van Rooyen et al., 2011). Die tweede stap in die studie was om die mededingende prestasie van die dadelbedryf empiries te meet op grond van hierdie handelsoriëntasie deur gebruik te maak van die relatiewe handelsvoordeel (relative trade advantage (RTA)) metode. Handelsdata afkomstig van FAOSTAT en Trademap is gebruik. Sedert 2001 het die Namibiese dadelbedryf konsekwent positiewe tendense vertoon, met RTA-waardes wat gewissel het tussen 0.40 en 4.0. In vergelyking met ander internasionale mededingers toon die resultate dat Tunisië verreweg die mees mededingende land is, met RTA-waardes van tussen 278 en 391. Namibië se dadelbedryf loop egter voor teen mededingers soos Suid-Afrika, die VSA, Kenia, Australië en Indië. In stap 3 is ’n bedryfswye opname onder bestuursvlak- rolspelers onderneem. Hierin is 72 faktore geïdentifiseer wat mededingende prestasie beïnvloed. Die 72 faktore is geëvalueer en deur middel van chi-kwadraat en eenrigting analise van variansie (ANOVA) geanaliseer in terme van hulle huidige impak as óf versterkend óf stremmend, en ook in terme van hulle relevansie vir die bedryf. Die resultate het getoon dat al die faktore as hoogs relevant (m.a.w. belangrik) vir die bedryf se mededingende prestasievlakke geëvalueer is, met 47% wat ’n versterkende rol gespeel het, terwyl 43% mededingende prestasie in die Namibiese dadelbedryf gestrem het. Verskille tussen die sienings oor die huidige impak en die langtermyn relevansie van die faktore het ’n ‘prestasiegaping’ voorsien wat die bedryf strategies aan aandag moet skenk om die mededingende prestasie te verbeter. Die drie top versterkende faktore was die grootte van die internasionale dadelmark, die beskikbaarheid van ongeskoolde arbeid en die gepastheid van die dadelproduksie (projek)-gebiede. Die stremmende faktore wat die belangrikste geag is, is geïdentifiseer as die gebrek aan privaatbefondsde wetenskaplike navorsing, die baie stadige tempo van groei in plaaslike markte en onvoldoende bedryfsbesteding op navorsing en ontwikkeling (R&D). In die vierde stap is Porter se mededingendheidsteorie (1990; 1998) toegepas om bedryfsdeterminante van mededingende prestasie af te lei. Die faktore vanaf stap 3 is in die ses Porter-diamant determinante gegroepeer. Hoofkomponent-ontleding (principal component analysis (PCA)) is onderneem om verskille en konsensus in die sienings van die respondente met betrekking tot die relevansie en impak van die faktore wat vir elke determinant geïdentifiseer is, te identifiseer. Die resultate het getoon dat daar groot verskille in opinies was met betrekking tot 52 faktore en konsensus oor 20 faktore wat die bedryf se mededingende prestasie beïnvloed. Deur die opinies oor die impakte en langtermyn relevansie van die geïdentifiseerde faktore te analiseer, is twee waardeketting bondels geïdentifiseer, naamlik daardie opinies of respondente wat direk in die produksieprosesse van dadels betrokke is (bondel 1); en dié wat ondersteuningsfunksies verskaf (bondel 2). Die resultate dui aan dat hoewel daar ooreenkomste in opinies binne die waardeketting van die dadelbedryf is, is daar belangrike verskille wat bestaan en aangeteken is. Verskille, waarvan kennis geneem moet word in strategiese bedryfsbeplanning, is aangeteken met betrekking tot toegang tot hoë kwaliteit tegnologie, die verkryging van langtermyn krediet, diversifikasie in die internasionale mark, die koste van gespesialiseerde tegnologiese dienste, die effek van wetlike en politiese faktore op die bedryf se strategiese posisie, die land se beleid van swart ekonomiese bemagtiging (SEB), en gesondheidskoste-implikasies. In stap 5 is die belangrikste bevindings in stappe 3 en 4, tesame met die sienings wat tydens ’n dadelbedryfinligtingsessie bekom is, in ’n strategiese besluitnemingsmatriks ingesluit. Klem is gele op faktore waaroor die bedryf grootliks saamstem. Die doel was om bedryfsvlakvoorstelle te ontwikkel om die mededingende prestasie van die bedryf te verhoog. Hierdie matriks het gefokus op die stremmende faktore waaroor ’n groot mate van bedryfsvlak-konsensus opgeteken is, tesame met daardie aksies wat die prestasie onmiddellik sou kon verbeter. Die voorstelle wat vooruitstaan is: ’n fokus op die ontwikkeling van menslike hulpbronne en vaardighede; koste-delende aktiwiteite; openbare-private vennootskappe in die ontwikkeling van projekvlak sosio-ekonomiese beleggingspakkette, met ’n belegging in langtermyn navorsing en ontwikkeling (R&D); opgradering van uitvoerfasiliteite; plaaslike markontwikkeling en verbeterde samewerking met nasionale handelaars; vermindering van bemarkingskostes; diversifikasie van uitvoermarkte; ontwikkeling van verteenwoordigende bedryfsvlak- instellings en ’n bedryfsvlak- strategiese plan; en die meer doeltreffende mobilisering van regeringsvlak-ondersteuning om ’n omgewing te ontwikkel wat bevorderlik is vir die bedryf om suksesvol te kan kompeteer.

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Sorghum (Sorghum bicolor) has the potential to be used as a cellulosic feedstock for ethanol production due to its diversity and wide adaptation to many different climates. With a wide range of diversity, this crop could be tailored specifically for use as a feedstock for ethanol production. Other factors such as water use efficiency, drought tolerance, yield potential, composition, and established production systems also make sorghum a logical choice as a feedstock for bioenergy production. The objectives of this study were to better understand the biomass potential of different types of sorghum that may be used for energy production, and determine the composition of these sorghums over the season to better understand biomass yield and composition over time. Six commercial sorghum cultivars or hybrids that represent sorghum types from grain to energy were evaluated near College Station, Texas during the 2008 and 2009 cropping years. An optimal harvest window (defined by maximum yield) was established for all genotypes, and significant variation was seen among the genotypes for fresh and dry biomass production. The later maturity genotypes, including the photo-period sensitive and modified photo-period sensitive type sorghums, produced the highest yields (up to 24 dry Mg/ha). Compositional analysis using near infrared reflectance spectroscopy (NIR) for lignin, hemicellulose, and cellulose was performed on a dry matter basis for the optimal harvest window for each genotype. Significant differences were seen in 2009 between the genotypes for lignin, hemicellulose, cellulose, ash and protein; with the earlier genotypes having higher percentage of lignin, and the later genotypes having lower percentages of lignin. Genotype x Environment interactions were also seen, and show the significance that rainfall can have. Based on this research, grain sorghum could be harvested first, followed by photo-period insensitive forage varieties, then moderately photo-period sensitive forage varieties followed by dedicated bioenergy sorghums (that are full photo-period sensitive), allowing for a more constant supply of feedstock to processing plants. Sweet sorghums would also allow the end user to obtain biomass when needed, however these types of sorghum may be much better suited to a different end application (i.e. crushing the stalks to obtain the juice).

Teaching children with autism to interact with their typically developing peers can be a challenge. Previous research has documented that there are many effective ways to teach social interaction; however, these interventions were implemented almost exclusively by trained professionals. The purpose of this study was to assess the effectiveness of parent-implemented contextually supported play dates. Specifically, two parents were taught to use mutual reinforcement and to design cooperative arrangements to help their child with autism to interact with a typical peer in their homes. Two independent reversal designs were used to demonstrate a functional relationship between parent-supported contextually supported play dates and an increase in synchronous reciprocal interactions for both participants. Social validity was also high for both parents; however, there was no consistent impact on participant, confederate, or parent affect. The results are discussed with reference to previous research, future directions, and implications for practice.