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You searched for subject:(opslag planten ). Showing records 1 – 2 of 2 total matches.

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1. Neya, O. Conservation of tree seeds from tropical dry-lands.

Degree: 2006, NARCIS

The tropical trees, Azadirachta indica (neem), Lannea microcarpa, Sclerocarya birrea and Khaya senegalensis, are important multipurpose species. Unfortunately, difficult seed storage behaviour limits the utilization of these species in reforestation programs and agroforestry systems. This thesis presents the results of investigations aimed at a better understanding of the seed biology, particularly focussed on the improvement of seed survival after drying and subsequent dry storage. Seeds collected from several stands in Burkina Faso were studied in an attempt to elucidate the causes of viability loss and improve life span. Initially it was thought that the difficulty in storing seeds of these species is due to intolerance of desiccation and sensitivity to low (subzero 0C) storage temperatures. However, the results of the current study indicated that other factors are responsible for the difficult storage behaviour of these seeds. When the moisture content (MC) was reduced from 27 to 5%, neem seeds became sensitive to rehydration temperatures below 25°C, resulting in a noticeable decrease in germination percentage. Rehydration of these dried seeds at elevated temperatures (25-400C) for one hour prior to further incubation at 300C substantially improved germination to a level comparable to that of fresh seeds (27% MC). We concluded that neem seed is desiccation tolerant, but that during drying its germination requirements change, which is the main cause of its difficult storage behaviour.Germination capability of S. birrea seeds was low in all seed lots at harvest, but improved substantially during drying and/or dry storage. Improvement of germination with drying is completely in contrast with what would happen in a desiccation-sensitive seed. We interpreted the observed increase in germination during drying and dry storage as resulting from the slow disappearance of an initially present physiological dormancy. Seeds of S. birrea thus behave as orthodox seeds, but the irregularity in their germination behaviour has obviously contributed to discrepancies between reports on the species seed biology.Seeds of L microcarpa harvested in three successive years were extremely variable as to their germinability and storability. Some seed accessions had a generally low germination, while others had an initially high germination. Drying did not affect germination capability of the poorly germinating seed accessions, but did so in the well germinating accessions. These observations would suggest that seeds can be either tolerant or sensitive to desiccation. However, when mechanically scarified prior to germination tests, seeds from all accessions germinated at high percentage (>80%), regardless of MC and age. This indicates that seeds experienced germination constraints upon drying rather than being sensitive to desiccation. Imbibed, intact seeds that failed to germinate displayed a moderate rate of respiration with RQ values< 1, which indicates that the seed coat is permeable to water and respiratory gases. On scarification,… Advisors/Committee Members: Wageningen University, Linus van der Plas, Folkert Hoekstra.

Subjects/Keywords: zaden; bomen; plantenfysiologie; azadirachta indica; lannea; sclerocarya birrea; khaya senegalensis; zaadkieming; opslag; burkina faso; kiemkracht; Reproductie van planten; seeds; trees; plant physiology; azadirachta indica; lannea; sclerocarya birrea; khaya senegalensis; seed germination; storage; burkina faso; germinability; Plant Reproduction

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Neya, O. (2006). Conservation of tree seeds from tropical dry-lands. (Doctoral Dissertation). NARCIS. Retrieved from http://library.wur.nl/WebQuery/wurpubs/349263 ; urn:nbn:nl:ui:32-349263 ; urn:nbn:nl:ui:32-349263 ; http://library.wur.nl/WebQuery/wurpubs/349263

Chicago Manual of Style (16th Edition):

Neya, O. “Conservation of tree seeds from tropical dry-lands.” 2006. Doctoral Dissertation, NARCIS. Accessed October 20, 2019. http://library.wur.nl/WebQuery/wurpubs/349263 ; urn:nbn:nl:ui:32-349263 ; urn:nbn:nl:ui:32-349263 ; http://library.wur.nl/WebQuery/wurpubs/349263.

MLA Handbook (7th Edition):

Neya, O. “Conservation of tree seeds from tropical dry-lands.” 2006. Web. 20 Oct 2019.

Vancouver:

Neya O. Conservation of tree seeds from tropical dry-lands. [Internet] [Doctoral dissertation]. NARCIS; 2006. [cited 2019 Oct 20]. Available from: http://library.wur.nl/WebQuery/wurpubs/349263 ; urn:nbn:nl:ui:32-349263 ; urn:nbn:nl:ui:32-349263 ; http://library.wur.nl/WebQuery/wurpubs/349263.

Council of Science Editors:

Neya O. Conservation of tree seeds from tropical dry-lands. [Doctoral Dissertation]. NARCIS; 2006. Available from: http://library.wur.nl/WebQuery/wurpubs/349263 ; urn:nbn:nl:ui:32-349263 ; urn:nbn:nl:ui:32-349263 ; http://library.wur.nl/WebQuery/wurpubs/349263

2. Nieuwenhuizen, A.T. Automated detection and control of volunteer potato plants.

Degree: 2009, NARCIS

High amounts of manual labor are needed to control volunteer potato plants in arable fields. Due to the high costs, this leads to incomplete control of these weed plants, and they spread diseases like Phytophthora infestans to other fields. This results in higher environmental loads by curative spraying of crop protection chemicals, which is in contradiction to the required decreased use of crop protection chemicals to save the environment. Therefore, the main objective of this thesis was “to develop a system for automated detection and control of volunteer potato plants”. A systematic design approach was used to define a program of requirements and to identify and order possible solutions to accomplish the detection and control. The main requirements were a travel speed of up to 2 m s-1, resolution of control at least 10×10 mm, work under variable natural light conditions, control of volunteer plants > 95%, and undesired control of sugar beet plants < 5%. The design strategy resulted in color and near-infrared machine vision as detection method and a micro-sprayer for application of glyphosate as a result. Furthermore, issues were identified that required further investigation to successfully come to a proof of principle machine. The research was then focused on: - Detection of volunteer potato plants, - Control of volunteer potato plants, - Real-time implementation of integrated detection and control on a proof of principle machine. For the purpose of detection of volunteer potato plants, the narrow band spectral reflectance properties of volunteer potato plants and sugar beet plants were analyzed. Narrow band spectral measurements were done in 2006 and 2007 on two different fields. This resulted in 15 datasets on clay and sand soil. Discriminating wavebands were selected and classified with neural networks and statistical discriminant analysis. A neural network with two hidden neurons performed best for classification. Two sensors were used covering the range from 450 to 900 nm and from 900 to 1650 nm. Both visible and near infra-red wavebands were responsible for discrimination. From the analysis 450, 765, and 855 nm from sensor 1 and 900, 1440, and 1530 nm from sensor 2 were identified as important discriminative wavebands. However, the discriminative wavelengths depended on field and crop status and could not be generalized. Ten wavebands that were optimally adapted to the datasets gave 99% true negative classification of volunteer potato plants. On the other hand, a fixed set of three wavebands that was not adapted to the individual datasets gave 80% true negative classification of volunteer potato plants. This indicates that adaptive feature sets are required for classification. The development of the machine vision detection system started with measurements in 2005. Color based detection showed that the difference in classification results was larger between fields than the difference between a static neural network and static Bayesian classification. Then, machine… Advisors/Committee Members: Wageningen University, Eldert van Henten, Jan Willem Hofstee.

Subjects/Keywords: opslag (planten); Solanum tuberosum; aardappelen; suikerbieten; detectie; onkruidbestrijding; automatisering; machine vision; sproeiapparatuur voor kleine oppervlakken; Mechanisatie; Meet- en regeltechniek; volunteer plants; Solanum tuberosum; potatoes; sugarbeet; detection; weed control; automation; machine vision; small plot sprayers; Mechanization; Measurement and Control Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Nieuwenhuizen, A. T. (2009). Automated detection and control of volunteer potato plants. (Doctoral Dissertation). NARCIS. Retrieved from http://library.wur.nl/WebQuery/wurpubs/383380 ; urn:nbn:nl:ui:32-383380 ; urn:nbn:nl:ui:32-383380 ; http://library.wur.nl/WebQuery/wurpubs/383380

Chicago Manual of Style (16th Edition):

Nieuwenhuizen, A T. “Automated detection and control of volunteer potato plants.” 2009. Doctoral Dissertation, NARCIS. Accessed October 20, 2019. http://library.wur.nl/WebQuery/wurpubs/383380 ; urn:nbn:nl:ui:32-383380 ; urn:nbn:nl:ui:32-383380 ; http://library.wur.nl/WebQuery/wurpubs/383380.

MLA Handbook (7th Edition):

Nieuwenhuizen, A T. “Automated detection and control of volunteer potato plants.” 2009. Web. 20 Oct 2019.

Vancouver:

Nieuwenhuizen AT. Automated detection and control of volunteer potato plants. [Internet] [Doctoral dissertation]. NARCIS; 2009. [cited 2019 Oct 20]. Available from: http://library.wur.nl/WebQuery/wurpubs/383380 ; urn:nbn:nl:ui:32-383380 ; urn:nbn:nl:ui:32-383380 ; http://library.wur.nl/WebQuery/wurpubs/383380.

Council of Science Editors:

Nieuwenhuizen AT. Automated detection and control of volunteer potato plants. [Doctoral Dissertation]. NARCIS; 2009. Available from: http://library.wur.nl/WebQuery/wurpubs/383380 ; urn:nbn:nl:ui:32-383380 ; urn:nbn:nl:ui:32-383380 ; http://library.wur.nl/WebQuery/wurpubs/383380

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