Spatial and Temporal Stability of Weed Patches in Cereal Fields under Direct Drilling and Harrow Tillage

Abstract

The adoption of conservation agriculture (CA) techniques by farmers is changing the dynamics of weed communities in cereal fields and so potentially their spatial distribution. These changes can challenge the use of site-specific weed control, which is based on the accurate location of weed patches for spraying. We studied the effect of two types of CA (direct drilling and harrow-tilled to 20 cm) on weed patches in a three-year survey in four direct-drilled and three harrow-tilled commercial fields in Catalonia (North-eastern Spain). The area of the ground covered by weeds (hereafter called “weed cover”) was estimated at 96 to 122 points measured in each year in each field, in 50 cm × 50 cm quadrats placed in a 10 m × 10 m grid in spring. Bromus diandrus, Lolium rigidum, and Papaver rhoeas were the main weed species. The weed cover and degree of aggregation for all species varied both between and within fields, regardless of the kind of tillage. Under both forms of soil management all three were aggregated in elongated patterns in the direction of traffic. Bromus was generally more aggregated than Lolium, and both were more aggregated than Papaver. Patches were stable over time for only two harrow-tilled fields with Lolium and one direct-drilled field with Bromus, but not in the other fields. Spatial stability of the weeds was more pronounced in the direction of traffic. Herbicide applications, crop rotation, and traffic seem to affect weed populations strongly within fields, regardless of the soil management. We conclude that site-specific herbicides can be applied to control these species because they are aggregated, although the patches would have to be identified afresh in each season.

Multiscale properties of weeds in no-till system

“…Weeds compete with agricultural crops for water and nutrients (Booth et al, 2003;Brighenti, Oliveira, 2011;Yamauti et al, 2011), and have high spatial (Schaffrath et al, 2007;Jurado-Expósito et al, 2021) and temporal variability (Chiba et al, 2010;Izquierdo et al, 2020).…”

Assessment of Weed Classification Using Hyperspectral Reflectance and Optimal Multispectral UAV Imagery

“…Weeds are unwanted plants that can damage and reduce crop yields, becoming worse over time if no action is taken to control the growth rate of the weeds. The competition for moisture, nutrients, and sunlight between the weeds and crops affects crop yields, which can be reduced by 45-95% [1][2][3]. The use of chemicals is widespread because of their effectiveness.…”

“…; however, because of the diversity of weed and due to herbicide resistance [4], this is not a long-term solution. The excessive use of herbicides harms crops and increases the end product price [3], in addition to jeopardizing environmental protection efforts [4] and leading to soil contamination [5], unless natural herbicides made of organic acids or essential oils are employed to mitigate these negative impacts; however, organic herbicides can be expensive.…”

Monitoring the Spatial Variability of Knapweed (Centaurea diluta Aiton) in Wheat Crops Using Geostatistics and UAV Imagery: Probability Maps for Risk Assessment in Site-Specific Control

“…Site-specific weed management (SSWM) is the application of the precision agriculture concept to one particular aspect of agricultural production: weed control. Site-specific weed management is based on the fact that weed populations commonly have a patchy distribution within crop fields [2][3][4][5][6][7][8][9][10][11], and SSWM implies applying chemical and/or physical weed control measures only where and when they are really needed [12]. Site-specific management is already commonplace in many aspects of farming.…”