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Lack of automatic weed detection tools has hampered the adoption of site-specific weed control in cereals. An initial object-oriented
algorithm for the automatic detection of broad-leaved weeds in cereals developed by SINTEF ICT (Oslo, Norway) was evaluated.
The algorithm (“WeedFinder”) estimates total density and cover of broad-leaved weed seedlings in cereal fields from near-ground red–green–blue images.
The ability of “WeedFinder” to predict ‘spray’/‘no spray’ decisions according to a previously suggested spray decision model for spring cereals was
tested with images from two wheat fields sown with the normal row spacing of the region, 0.125 m. Applying the decision model
as a simple look-up table, “WeedFinder” gave correct spray decisions in 65–85% of the test images. With discriminant analysis, corresponding mean rates were 84–90%.
Future versions of “WeedFinder” must be more accurate and accommodate weed species recognition. 相似文献
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Lars Olav Brandsæter Anne Kjersti Bakken Kjell Mangerud Hugh Riley Ragnar Eltun Haldor Fykse 《European Journal of Agronomy》2011,34(4):239-246
To ensure optimum conditions for organic cereal growing, it is important to minimize both compaction and soil inversion depth. The relative effects of using light versus heavier tractors, shallow versus deeper ploughing and on-land versus in-furrow wheel placement during ploughing were investigated in three-year organic rotations dominated by cereals with naturally infested stands of perennial weeds. The second part of the experiments was carried out in continuous barley with transplanted root fragments of Cirsium arvense (L.) Scop. and rhizome pieces of Elymus repens (L.) Gould. Ploughing was performed in spring under favourable weather conditions. Neither tractor weight nor wheel placement influenced decisively the numbers and above-ground biomass of perennial weeds. Depth of ploughing, on the other hand, affected both perennial weed infestation and yield levels consistently. Weed numbers and the total above-ground weed biomass were mostly 50% lower with deep ploughing (25 cm) than with shallow ploughing (15 cm). The greatest advantage of deep ploughing appeared in the control of C. arvense, which in some cases was reduced by more than 90% compared to shallow ploughing. In organic rotations dominated by cereals, therefore, combating of perennial weeds by deep ploughing may be more important than factors such as tractor weight and wheel placement. 相似文献
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M. Goul Thomsen L.O. Brandsæter H. Fykse 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(8):693-700
Abstract Single and combined effects were studied of root length, burial depth, cutting and competition from a seasonal green manure crop on the growth and development of C. arvense from roots found in the upper soil layer. The experiment was performed under field conditions and partly repeated in a green house. The green manure consisted of a mixture of phacelia, common vetch, red clover and Italian ryegrass. Root fragments of 5 and 10 cm length were buried at 5 and 15 cm soil depth, simulating soil tillage. Use of green manure alone reduced growth of C. arvense more than any other single factor (81–99%), while root length and burial depth were more variable in their effect (0–96% reduction). Combined treatments involving both green manure, deep root burial (15 cm) and short root length (5 cm) reduced growth of C. arvense consistently by 95–100%. At the minimum regenerative capacity of C. arvense the number of leaves was 3–7 in plots with no green manure, at which time cutting had the greatest effect on regrowth the following year. The level for minimum regenerative capacity was not possible to decide for C. arvense growing in competition with green manure. Combined multiple treatments in spring, including use of green manure and mechanical operations in the upper soil layers, appear to be a potential means of reducing C. arvense infestations. 相似文献
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Therese With Berge Haldor Fykse Are H. Aastveit 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):212-221
Abstract A major obstacle to patch spraying of broad-leaved weeds in cereals is a cost-effective method to assess within-field heterogeneity of the weed population. One method could be a camera mounted in front of the spraying vehicle, online image analysis, and field sprayer shifting between ‘on’ and ‘off’ as the predefined weed damage threshold level is reached. Because such a camera will capture a very limited area (<1 m2) compared to the sprayer width (several m), success of this method requires that spraying decisions vary little within boom width, thereby causing few spraying errors. This approach was evaluated by simulations for varying boom widths and three levels of a weed damage threshold model. Potential herbicide reductions compared to blanket application were also simulated. The average potential herbicide reductions estimated as proportions of fields below the threshold, were 60%, 64% and 53% for the original, 25% increased and 25% reduced threshold levels, respectively. The simulated herbicide reductions were not influenced by boom width, but varied significantly between fields, and between threshold levels. As evaluated by spraying errors, the suitability of the suggested approach will increase by decreasing boom width, vary between fields, and in some fields vary between the threshold levels. For boom widths of 15 m and 24 m, the spraying errors were about 10% and 15%, respectively, where omission of spraying areas above the threshold constituted 5% and 8%, respectively. 相似文献
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