Browsing by Author "Blackmore, S."

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    Design of the robotic self-travelling sprinkler system
    (1999-08) Ozaki, Yuriko; Blackmore, S.
    A conventional rain gun system is adversely affected by windy conditions. Therefore, the robotic self-travelling sprinkler (STS) system that controls the head and the water supply with relation to instant windy conditions. The robotic STS head has two degrees of freedom; sector and trajectory angles, driven by stepper motors to follow the control model, which are found by applying prediction models of water distribution, Centre of volume and Semi-empirical models. As a result, it was shown that the control for the sector angle compensated for the horizontal water distortion from wind, however, the trajectory angle was found to need more data to model the optimum trajectory angle. To control the water supply, a cut-off solenoid valve was installed and shut when wind was over 6 m/s upwind and 7 m/s downwind. This indicated that the trajectory angle was less than 10 degrees above horizontal. Under such windy conditions, water can not be distributed as far from the STS as required or becomes spray, which cannot reach to the ground. As the experimental results showed, the system enabled to minimize the commercially ineffective water distribution. A chemigation system was added, which can injects chemicals into the main water flow. The system enables farmers to save the cost for extra chemigation equipment. The process of the system while working can be checked by the interactive communication system between the embedded computer and the user’s computer. Therefore, this system made the robotic STS system more reliable, furthermore, it enabled the user’s computer to read and save the data sent from the field controller unit. This robotic STS system can distribute water or chemicals to the required area, even if up to the irregular boundaries,(fence lines, comers of fields), with the minimum water supply. Also, the system is ready to incorporate treatment maps and DGPS. In other words, it is possible to feed the adequate amount of water or chemicals which varies depending on the different regions of fields, species of plants, and seasons.
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    Developing strategies for spatially variable nitrogen application in cereals II: wheat
    (Elsevier , 2003-04) Welsh, J. P.; Wood, G. A.; Godwin, R. J.; Taylor, John C.; Earl, R.; Blackmore, S.; Knight, S. M.
    For precision agriculture to provide both economic and environmental benefits over conventional farm practice, management strategies must be developed to accommodate the spatial variability in crop performance that occurs within fields. Experiments were established in crops of winter barley (Hordeum vulgare L.) over three seasons. The aim of which was to evaluate a set of variable rate nitrogen strategies and examining the spatial variation in crop response to applied N. The optimum N application rate varied from 90 to in excess of 160 kg [N] ha−1 in different parts of the field, which supports the case for applying spatially variable rates of N. This, however, is highly dependent on seasonal variations, e.g. the quantity and distribution of rainfall and the effect that this has on soil moisture deficits and crop growth. Estimates of yield potential, produced from either historic yield data or shoot density maps derived from airborne digital photographic images, were used to divide experimental strips into management zones. These zones were then managed according to two N application strategies. The results from the historic yield approach, based on 3 yr of yield data, were inconsistent, and it was concluded that that this approach, which is currently the most practical commercial system, does not provide a suitable basis for varying N rates. The shoot density approach, however, offered considerably greater potential as it takes account of variation in the current crop. Using this approach, it was found that applying additional N to areas with a low shoot population and reducing N to areas with a high shoot population resulted in an average strategy benefit of up to 0·36 t ha−1 compared with standard farm practice.
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    Developing Strategies for spatially variable nitrogen application in cereals, I: Winter barley
    (Elsevier , 2003-04) Welsh, J. P.; Wood, G. A.; Godwin, R. J.; Taylor, John C.; Earl, R.; Blackmore, S.; Knight, S. M.
    For precision agriculture to provide both economic and environmental benefits over conventional farm practice, management strategies must be developed to accommodate the spatial variability in crop performance that occurs within fields. Experiments were established in crops of winter barley (Hordeum vulgare L.) over three seasons. The aim of which was to evaluate a set of variable rate nitrogen strategies and examining the spatial variation in crop response to applied N. The optimum N application rate varied from 90 to in excess of 160 kg [N] ha−1 in different parts of the field, which supports the case for applying spatially variable rates of N. This, however, is highly dependent on seasonal variations, e.g. the quantity and distribution of rainfall and the effect that this has on soil moisture deficits and crop growth. Estimates of yield potential, produced from either historic yield data or shoot density maps derived from airborne digital photographic images, were used to divide experimental strips into management zones. These zones were then managed according to two N application strategies. The results from the historic yield approach, based on 3 yr of yield data, were inconsistent, and it was concluded that that this approach, which is currently the most practical commercial system, does not provide a suitable basis for varying N rates. The shoot density approach, however, offered considerably greater potential as it takes account of variation in the current crop. Using this approach, it was found that applying additional N to areas with a low shoot population and reducing N to areas with a high shoot population resulted in an average strategy benefit of up to 0·36 t ha−1 compared with standard farm practice.
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    Non-Invasive soil property measurement for precision farming
    (Cranfield University, 1999-10-01) Waine, Toby William; Blackmore, S.
    This work investigates the application of new sensors to enable agronomists and farm managers to make decisions for variable treatment strategies at key crop growth stages. This is needed to improve the efficiency of crop production in the context of precision farming. Two non-invasive sensors were selected for investigation. These were: 1) The MGD-1 ion mobility gas detector made by Environics OY, Finland. 2) The EM38 electromagnetic induction (EMI) sensor made by Geonics Inc., Canada. The gas detector was used to determine residual nitrogen and to measure carbon dioxide gas as a surrogate indicator of soil quality. In the latter, increased microbial carbon dioxide production was expected on soils with high organic matter content. Overall, the results of gas detection were disappointing. The main problems inherent in the system were; lack of control of the gas sampling, insufficient machine resolution and cross contamination. This led to the decision to discontinue the gas detection research. Instead, the application of electromagnetic induction (EMI) to measure soil variation was investigated. There were two principle advances in the research. Firstly the application of EMI to the rapid assessment of soil textural class. Secondly the mapping of available water content in the soil profile. These were achieved through the development of a new calibration procedure based on EMI survey of the sites at field capacity, working with field experiments from five sites over two years. Maps of total available water holding capacity were produced. These were correlated with yield maps from wet and dry seasons and used to explain some of the seasonal influences on the spatial variation in yield. A product development strategy for a new EMI sensor was considered which produced a recommendation to design a new EMI sensor specifically for available water content and soil texture mapping, that could be mounted on a tractor. For the first time, this procedure enables routine monitoring of the spatial variation in available water content. This enables the effects of seasonal and spatial variation to be included in crop models, targeted irrigation and to aid decisions for the variable application of inputs.
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    Spatial and temporal trends in yield map data
    (2004-08-26T14:57:47Z) Blackmore, S.; Fountas, Spyridon; Moore, Mark R.; Godwin, R. J.
    As part of the research programme to develop precision farming management guidelines, started in 1995/96 on four sites in England, yield map data were recorded from 1995 onwards. Their trends were used as an input to assist in the development of management strategies, namely applying nitrogen based upon long term (historic) yield data (Welsh et al., 2001a and 2001b). This section gives the simplest analysis of this data showing the variation in yield both i) within the field (spatial), and ii) between years (temporal).