A decision algorithm for patch spraying |
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| Authors: | S Christensen T Heisel† A M Walter† & E Graglia† |
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| Institution: | Department of Agricultural Engineering, Danish Institute of Agricultural Sciences, Research Centre Bygholm, Horsens, Denmark,;and Department of Crop Protection, Danish Institute of Agricultural Sciences, Research Centre Flakkebjerg, Slagelse, Denmark |
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| Abstract: | It has been established that weeds are spatially aggregated with a spatially varying composition of weed species within agricultural fields. Site‐specific spraying therefore requires a decision method that includes the spatial variation of the weed composition and density. A computerized decision method that estimates an economic optimal herbicide dose according to site‐specific weed composition and density is presented in this paper. The method was termed a ‘decision algorithm for patch spraying’ (DAPS) and was evaluated in a 5‐year experiment, in Denmark. DAPS consists of a competition model, a herbicide dose–response model and an algorithm that estimates the economically optimal doses. The experiment was designed to compare herbicide treatments with DAPS recommendations and the Danish decision support system PC‐Plant Protection. The results did not show any significant grain yield difference between DAPS and PC‐Plant Protection; however, the recommended herbicide doses were significantly lower when using DAPS than PC‐Plant Protection in all years. The main difference between the two decision models is that DAPS integrates crop–weed competition and estimates the net return as a continuous function of herbicide dose. The hypothesis tested is that the benefit of using lower herbicide doses recommended by DAPS would disappear after a few years because weed density will increase and thus require higher doses. However, the results of weed counting every year did not confirm this hypothesis. |
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| Keywords: | decision algorithms patch spraying weed management economic optimal herbicide dose cereals |
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