Weed infestations in soybean grown in succession to cropping systems with sorghum and cover plants

Abstract

The objective of this work was to evaluate the influence of sorghum and cover plant cropping systems before soybean cultivation on the occurrence of weeds during soybean growing in the Brazilian Cerrado. The experiment was carried out in a randomized complete block design, with four replicates. The treatments comprised six cropping systems before soybean: sorghum (Sorghum bicolor), palisade grass (Urochloa brizantha), and Congo grass (Urochloa ruziziensis) as cover plants, alone or intercropped, in addition to fallowing. Weeds were evaluated as to: density, dry matter mass, diversity, importance value, and similarity. The greatest similarity of weeds ocurred in single crops of sorghum, palisade grass, and Congo grass, in comparison with their intercroppings. Congo grass before soybean promoted a greater reduction in weed diversity overtime, when compared with palisade grass. The absence of cover crops before soybean cultivation increased weed infestation during the soybean cycle. The cropping systems with sorghum intercropped with cover crops before the soybean cultivation affect the diversity and the importance value of weed species.

Intercropping sorghum and grasses during off-season in Brazilian Cerrado

“…The straw production of the forages can afford gains in soil fertility and soybean yield (Crusciol et al, 2015;Andrade et al, 2017). Furthermore, systems like these have the potential to keep the weed population below the economic injury level in soybean in succession, since controlled grass development is a strategy for reducing but not eradicating weeds (Sodré-Filho et al, 2020).…”

“…Congo grass (Urochloa ruziziensis (R. Germ. and Evrard) Crins) is another forage found extensively in the Cerrado, and it is easily controlled and desiccated under no-tillage planting to soybean in succession (Nakao et al, 2019;Sodré-Filho et al, 2020). Despite their slow initial development and low plant height, these species produce high amounts of dry matter during the dry season and show significant potential for straw production (Carvalho et al, 2017).…”