Evaluation of two patch spraying systems in winter wheat and maize

Abstract

Gutjahr C, Sökefeld M & Gerhards R (2012). Evaluation of two patch spraying systems in winter wheat and maize. Weed Research52, 510–519. Summary Fifteen field experiments were conducted in winter wheat and maize to analyse the spatial distribution of weed species and to evaluate two systems of site‐specific weed control. Fields were divided into cells and weed densities for all weed species were counted in each cell. Weed species were then grouped into annual broad‐leaved species, grass weeds and Galium aparine in winter wheat and annual broad‐leaved species, grass weeds and perennials in maize. Weed control thresholds were set for each group of weed species and different herbicides were sprayed in cells where the weed control threshold was exceeded. All three weed species groups were distributed heterogeneously within and between the fields, with densities ranging from 0 to more than 2000 plants m−2. Site‐specific weed control was realised with a GPS‐controlled multiple‐tank sprayer, containing three separate spray lines for each of the three application maps. In winter wheat, site‐specific weed control using a multiple‐tank sprayer resulted in 70% untreated area compared with uniform applications across the whole field. Simulated site‐specific weed control using a conventional sprayer with a tank mixture only resulted in 37% untreated area. In maize, 47% of the area remained untreated using the multiple‐tank sprayer and 6% using a conventional sprayer and tank mixtures. Efficacy of site‐specific weed control was good in all fields. The results demonstrate the need for combining weed mapping and new application technologies for patch spraying.

Effect of site-specific weed management in winter crops on yield and weed populations

“…For example, Häusler et al (1998) found that herbicide applications in two winter wheat fields were necessary for 24% and 35% of the area against G. aparine L., for 25% and 31% of the area against other dicotyledonous weeds, and for 55% and 7.5% of the area against grasses. Gutjahr et al (2012) calculated herbicide savings in 11 winter wheat fields treated with SSWM. Average untreated area was 70% for broad-leaved species and 59% for grass weeds.…”

Unsupervised Classification Algorithm for Early Weed Detection in Row-Crops by Combining Spatial and Spectral Information

“…For example, in the case of chemical tools, various works have already demonstrated the technical feasibility of precision weed control implements. Numerous works addressed the use of chemical sprayer able to turn on or off boom sections or individual nozzles [4][5][6][7][8] to applied herbicides specifically on clusters or individual weed plants. Concerning physical weed management, technologies had also been developed to guide weeding devices according to weed detection in fields [9].…”

Sprouting Ability and Seasonal Changes of Sugar Concentrations in Rhizomes of Calystegia sepium and Roots of Convolvulus arvensis

“…The species mostly occur in spring crops such as maize, sugar beet and sunflower, but also infest cereal crops, vineyards and orchards (Mehrtens et al 2005, Pfirter et al 1997, Parsons & Cuthbertson 2001. Due to their predominant vegetative propagation they often grow in aggregated patches (Gutjahr et al 2012) and tend to increase in abundance in the absence of tillage (Streit et al 2002, Rusu et al 2006, Knezevic et al 2008. The bindweeds from the family of Convolvulaceae are in direct competition with the crop by their climbing habit due to physico-mechanical stimuli (Kleinsteuber et al 1996).…”