Weed communities respond to changes in crop sequence composition and land use intensification

ANDRADE, JOSÉ F.; POGGIO, SANTIAGO L.; SATORRE, EMILIO H.

Praga

Congreso; 7th International Weed Science Congress; 2016

International Weed Science Society

While land use intensification and crop diversification increase land productivity, they may also affect weed community composition. Experiments were set up at three locations in the Rolling Pampa, Argentina to assess weed community shifts due to the implementation of cropping systems differing in the composition and number of crops in a single season. We also studied if weed communities converge when the same sequence is cropped the following two years. Treatments included five cropping systems during the first year: (1) winter cereal/soybean double crop, (2) field pea/soybean double crop, (3) field pea/maize double crop, (4) maize single crop and (5) soybean single crop. All treatments were cropped by the same sequence in the following two years (wheat/soybean double crop and maize). Weed species frequency was surveyed three times, once during each summer crop. Composition shifts between sites, treatments, cropped species, and seasons were evaluated with a multivariate analysis of variance (NMDS) based on dissimilarities (Adonis). Changes in weed community structure were analyzed through the frequency-ranking relationship.Weed communities diff ered among sites (P