Browsing by Author "Manning M"

Now showing 1 - 3 of 3
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    A review of practices in precision application of granular fertilisers
    Grafton MCE; Yule I; Manning M; Nelson, W
    There is an implicit assumption in cited literature on precision agriculture (PA) that spreading of fertiliser is performed perfectly in the field leading to uniform application, this is not true. Variation can be large and often the actual performance of spreading equipment used has never been measured or verified. In various countries around the world there are quality assurance (QA) systems designed to achieve a prescribed level of performance. Even within these QA schemes limited testing is undertaken and always under perfect or near perfect conditions. The test methods are designed to establish an acceptable bout width which meets an acceptable evenness of spread if driven accurately. The test does not take into account wind conditions (except for requiring less than 15kmhr-1 for testing), humidity, slope, terrain or the instrumentation to maintain the desired bout width. This paper examines the effect of the farm environment and the physical characteristics of fertilisers on the spread patterns of fertilisers in the field. Fertilisers with heterogeneous particle size distributions proved to have more robust spread patterns under field conditions than those with homogeneous particle size distributions.
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    Capability of ground fertiliser placement when spread from a fixed wing aircraft
    (13/04/2016) Chok S; Grafton M; Yule IJ; Manning M
    Aerial topdressing using differential rate application technology improves fertiliser spreading on hill country farms. However, the system’s ability to place fertiliser accurately and precisely within an area needs to be determined. Accuracy was determined by comparing measured and intended application rates. Precision was indicated by the coefficient of variation (CV), which is the standard deviation of the measured application rate over the mean of this rate. Two trials were carried out, where aircraft deposited fertiliser at two application rates and fertiliser was captured using cone-shaped collectors. The average measured application rate for both trials was less than the intended rate. The CV ranged from 35 to 57%, and was lower than CV’s from pilot-operated hopper systems (78%). A one-way analysis of variance test found the difference between measured application rate in the high and low application zone was statistically significant. The results indicate work is required to improve the accuracy and precision of the differential rate system, however, the system shows promise. Keywords: differential rate application technology, aerial spreading, fertiliser placement
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    Mapping nutrient concentration in pasture using hyperspectral imaging
    (2015) Yule IJ; Pullanagari RR; Irwin M; McVeagh P; Kereszturi G; White M; Manning M