The purpose of a greenhouse is to maintain desirable growing conditions for plants during the different seasons of the year. The glass-covered greenhouse has been found to be suitable for this purpose through many yeara of use and improvement. It has been very popular for providing a controlled environment in which out-of-season crops can be grown and also as a research house for the study of plant growth. The sturdy construction required to support the weight of glass involves a high initial cost. With the development of plastic sheeting suitable for use as a glazing material, a new type of greenhouse has evolved. Greenhouses covered with plastic do not require the sturdy structure necessary to support glass, although a permanent construction may be used. To date the plastic greenhouse has found its greatest use as a temporary low cost structure. The possibility of growing crops intolerant of frost during the winter months in the southwestern United States where mild winters keep heating costs low, has increased interest in plastic greenhouses. Since high temperatures occur during the summer months in the Southwest, cooling as well as heating have to be provided if the greenhouse is to be operated through the entire year. This study was designed to measure the modification of the environment within a plastic greenhouse and to evaluate the growth response of tomatoes under these conditions. Studies were conducted to determine the temperatures which could be maintained in a plastic greenhouse during the summer, winter and spring seasons. The growth response of tomatoes under plastic was studied using winter and spring variety trials.

Thesis (M.Sc. (Crop Science)) --University of Limpopo, 2012 / Organic tomatoes are increasingly popular with larger market acceptance since organic farming uses limited or no artificial chemicals. Application of organic fertilisers such as cattle manure has potential to boost organic tomato productivity particularly under low input farming systems. However, information is required on the optimum level of manure application on different tomato cultivars to help emerging tomato farmers in South Africa. The objective of this study was to determine the relative response of yield and yield components among selected determinate and indeterminate tomato cultivars using different levels of cattle manure. Two separate field experiments were conducted at the University of Limpopo during 2007 and 2008 using a split plot design with three replications. Two sets of tomato cultivars were included in which one set consisted indeterminate types (Money Maker, Ox Heart and Sweetie) and the other determinates (Roma and Floradade). Cultivars were assigned as the main plot treatments with six rates of manure (0, 10, 20, 30, 40 and 50 in gram per plant) applied as the subplot treatments to each set. Results indicated significant interactions (P ≤ 0.01) between indeterminate tomato cultivars and levels of manure applied for fruit yield and fruit size in both experiments. Plant height showed variation from 78 to168 cm in Experiment I and 87 to 176 cm in Experiment II. During Experiment I fruit number varied from 23 to 91 per plant and 23 to 97 in Experiment II. Significant differences were detected among determinate cultivars on fruit yield varying from 7928 to 3 4705 kg per hectare during Experiment I and 3 169 to 2 9840 kg per hectare during Experiment II. Overall, the best level of manure for maximum fruit yield and greater fruit size was achieved at 40 g per plant in the indeterminate cultivar Sweetie. Conversely, the best level of manure for maximum fruit yield was achieved at 30 g per plant in determinate cultivar Roma. Thus, to achieve maximum yield, tomato growers could apply 600 and 800 kg per hectare manure on the determinate and indeterminate tomato cultivars, respectively. / the National Research Foundation (NRF)

Submitted by LEONARDO CORREIA COSTA (leonardocorreia08@gmail.com) on 2018-08-07T15:06:53Z No. of bitstreams: 1 TESE DOUTORADO 2018 - Leonardo Correia Costa.pdf: 1095091 bytes, checksum: 4ee6da2628585688570e203a0c45b0fb (MD5) / Approved for entry into archive by Neli Silvia Pereira null (nelisps@fcav.unesp.br) on 2018-08-08T16:40:27Z (GMT) No. of bitstreams: 1 costa_lc_dr_jabo.pdf: 1095091 bytes, checksum: 4ee6da2628585688570e203a0c45b0fb (MD5) / Made available in DSpace on 2018-08-08T16:40:27Z (GMT). No. of bitstreams: 1 costa_lc_dr_jabo.pdf: 1095091 bytes, checksum: 4ee6da2628585688570e203a0c45b0fb (MD5) Previous issue date: 2018-06-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / RESUMO - O nitrogênio (N) e potássio (K) são os nutrientes mais requeridos pelo tomate para processamento, sendo o N mais associado com o crescimento e produtividade das culturas, e o K com o aumento da qualidade de frutos, mas a interação das doses destes nutrientes com o ambiente em tomate para processamento industrial ainda é incipiente. Objetivou-se avaliar doses de N (0, 60, 120 e 180 kg ha 1) e de K (0, 100, 200, 300 e 400 kg ha-1 K2O) sobre a produtividade, rendimento de polpa e qualidade dos frutos de tomate ‘Heinz 9553’ para processamento industrial e realizar a análise de crescimento aos 14, 28, 42, 56, 70, 84, 96, 112 e 126 dias após o transplantio (DAT) em função do N aplicado. O experimento foi realizado de abril a agosto de 2015, no município de Barretos, Estado de São Paulo, Brasil. A fonte para o fornecimento de N foi a ureia e cloreto de potássio para K. A fertilização com 180 kg ha-1 N e de 400 kg ha-1 K2O proporcionou maior produtividade de frutos coloridos, vermelhos e total, e rendimento industrial de polpa de tomate. As doses de N e de K não afetaram os teores de betacaroteno e de licopeno. O teor de sólidos solúveis no tomate aumentou tanto com a fertilização nitrogenada quanto com a fertilização potássica. As doses altas de N e K diminuíram a firmeza dos frutos. O aumento de vitamina C do fruto respondeu em maior intensidade à adubação nitrogenada que a potássica. Com relação ao crescimento do tomateiro, a fertilização com 180 kg ha-1 N proporcionou maior área foliar, massa seca de folha, massa seca de parte área (folhas + hastes), massa seca de fruto, massa seca total, índice de área foliar, razão de área foliar e razão de massa de folha ao fim do ciclo. As menores taxa de crescimento relativo e área foliar específica foram verificadas com 180 kg ha-1. Para todas doses de N, a taxa de crescimento absoluto é pequena até 56 DAT e, posteriormente, as doses de N promoveram incremento diferenciado sobre o índice. / ABSTRACT - The nitrogen (N) and potassium (K) are the nutrients most required by the tomato for processing, N being more associated with crop growth and productivity, and K with increasing fruit quality, but the interaction of the doses of these nutrients with the environment in tomato for industrial processing is still incipient. The objective of this study was to evaluate N rates (0, 60, 120 and 180 kg ha-1) and K (0, 100, 200, 300 and 400 kg ha-1 K2O) on yield, pulp yield and fruit quality of tomatoes 'Heinz 9553' for industrial processing and to perform the growth analysis at 14, 28, 42, 56, 70, 84, 96, 112 and 126 days after transplanting (DAT) as a function of N applied. The experiment was carried out from April to August 2015, in the city of Barretos, State of São Paulo, Brazil. The source for the supply of N was urea and potassium chloride for K. Fertilization with 180 kg ha-1 N and 400 kg ha-1 K2O provided higher productivity of red, whole and colored fruits and industrial yield of pulp of tomato. The doses of N and K did not affect the levels of beta-carotene and lycopene. The content of soluble solids in tomatoes increased with both nitrogen fertilization and potassium fertilization. High doses of N and K decreased fruit firmness. The increase of vitamin C of the fruit responded more intensely to nitrogen fertilization than potassium. In relation to tomato growth, fertilization with 180 kg ha-1 N provided a larger leaf area, leaf dry mass, shoot dry mass (leaves + stems), dry fruit mass, total dry mass, leaf area index, leaf area ratio and leaf mass ratio at the end of the cycle. The lowest relative growth rate and specific leaf area were verified with 180 kg ha-1. For all doses of N, the absolute growth rate is small up to 56 DAT and, subsequently, the N doses promoted a differential increase over the index.

The purpose of greenhouse crop systems is to generate a high quality product at high production rates, consistently, economically, efficiently and in a sustainable way. To achieve this level of productivity, accurate monitoring and control of some processes of the entire biophysical system must be implemented. In addition, the proper selection of actions at the strategic, tactical and operational management levels must be implemented.Greenhouse management relies largely on human expertise to adjust the appropriate optimum values for each of the production and environmental parameters, and most importantly, to verify by observation the desired crop responses. The subjective nature of observing the plant responses, directly affects the decision-making process (DMP) for selecting these `optimums'. Therefore, in this study several decision support systems (DSS) were developed to enhance the DMP at each of the greenhouse managerial levels.A dynamic greenhouse environment model was implemented in a Web-based interactive application which allowed for the selection of the greenhouse design, weather conditions, and operational strategies. The model produced realistic approximations of the dynamic behavior of greenhouse environments for 28-hour simulation periods and proved to be a valuable tool at the strategic and operational level by evaluating different design configurations and control strategies.A Web-based crop monitoring system was developed for enhancing remote diagnosis. This DSS automatically gathered and presented graphically environmental data and crop-oriented parameters from several research greenhouses. Furthermore, it allowed for real-time visual inspection of the crop.An intelligent DSS (i-DSS) based on crop records and greenhouse environment data from experimental trials and from commercial operations was developed to characterize the growth-mode of tomato plants with fuzzy modeling. This i-DSS allowed the discrimination of "reproductive", "vegetative" and "balanced" growth-modes in the experimental systems, and the seasonal growth-mode variation on the commercial application.An i-DSS based on commercial operation data was developed to predict the weekly fluctuations of harvest rates, fruit size and fruit developing time with dynamic neural networks (NN). The NN models accurately predicted weekly and seasonal fluctuations of each variable, having correlation coefficients (R) of 0.96, 0.87 and 0.94 respectively, when compared with a dataset used for independent validation.