COVER CROPS IN THE OFF-SEASON IN THE WEED MANAGEMENT AT NOTILLAGE AREA

Fernando Couto De Araújo,Juliana Lourenço Nunes Guimarães,Fenelon Lourenço De Sousa Santos,Marco Antônio Moreira De Freitas,Adriano Stephan Nascente,Vinícius Silva Sousa

doi:10.1590/1983-21252021v34n106rc

Fernando Couto De Araújo, Juliana Lourenço Nunes Guimarães + Show 4 more

Open Access

https://doi.org/10.1590/1983-21252021v34n106rc

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Abstract

ABSTRACT Cover crops can provide suppression of weeds and together with chemical control make the proper management of weeds in agricultural areas. The objective of this study was to evaluate the effect of cover crop cultivation during the off-season on weed development in a no-tillage area. The experimental design was in randomized blocks scheme with six treatments and four replications. The treatments were: fallow (control), millet (Pennisetum glaucum) + crotalaria (Crotalaria spectabilis + C. juncea + C. ochroleuca), millet + pigeon pea (Cajanus cajans), millet + Urochloa ruziziensis, millet + Urochloa ruziziensis + pigeon pea and millet + buckwheat (Fagopyrum esculentum. The evaluations were done at 30, 75 and 225 days after sowing of the cover crops (DAS). The main growth weed species in the area were Cenchrus echinathus, Euphorbia heterophylla and Digitaria insularis. Fallow treatment showed greater number of weed species with density of 184 plants m-2, 9.0 species and with 527.8 g m-2 of dry matter mass at 225 DAS. In all treatments verified reduction in the density and mass of weeds dry matter compared to the fallow, with average of 30 plants m-2, 5.8 species and 7.9 g m-2 at 225 DAS, respectively. The use of cover crops is an important strategy for weed control in agricultural areas.

Highlights

The no-tillage system was designed using good land use practices, including minimal soil tillage, crop rotation and soil covered by the use of soil cover plants in periods without commercial crop (NASCENTE; STONE, 2018)
The most frequent weeds in the area were southern sandspur (Cenchrus echinatus), milkweed (Euphorbia heterophylla) and bitter grass (Digitaria insularis), with C. echinathus representing 80% of the total weed density in the areas fallow at 75 days after sowing cover crops (DAS)
Weeds compete for water, light and nutrients reducing crop development and can act as hosts for pests and diseases, cause allelopathic effects, hinder harvesting and reduce land value (GALON et al, 2018)

Summary

Introduction

The no-tillage system was designed using good land use practices, including minimal soil tillage, crop rotation and soil covered by the use of soil cover plants in periods without commercial crop (NASCENTE; STONE, 2018). One of the main options available within an integrated weed management system, especially as difficult to control, is the cultivation of cover plants during the off-season (autumn/winter), complemented by chemical management with herbicides (VARGAS; PASSOS; KARAM, 2018). In this way, these cover plants have a suppressive effect on an weed and their straw assists in the control and reduction of weed biomass production at the beginning of crop development (WERLANG et al, 2018). The cultivation of cover crops can stimulate the development of endophytic fungi capable of attacking weed seeds in the soil (VOLL et al, 2004) and provide an increase in population of seed predatory insects, which contribute to the reduction of certain species weeds (COSTA et al, 2018)

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