Weed infestations of winter wheat depend on the forecrop and the tillage system

Andrzej Woźniak,Dorota Gawęda,Elżbieta Harasim

doi:10.5586/aa.1744

Abstract

In-crop weed infestation is affected by both habitat conditions and agronomic practices, including the forecrop and tillage treatments used. This study evaluated the effect of the forecrop and the tillage system on species composition, number and dry weight of weeds in a winter wheat ‘Astoria’. A field study was carried out over the period 2014–2017 at the Uhrusk Experimental Farm (SE Poland), on a mixed rendzina soil with a grain-size distribution of sandy loam. Wheat was grown in a four-course crop rotation: soybean – winter wheat – rapeseed – winter wheat. The experimental factors were as follows: a forecrop of winter wheat (soybean and winter rapeseed) and a tillage system (ploughing and no-tillage). Avena fatua was the most frequently occurring weed in the wheat crop sown after soybean, whereas after winter rapeseed it was Viola arvensis. Viola arvensis was the dominant weed under both tillage systems. In all experimental treatments, the species Viola arvensis and Cirsium arvense were characterized by the highest constancy (Constancy Class V and IV), and also Veronica arvensis after the previous winter rapeseed crop. In the wheat crop sown after winter rapeseed, the number of weeds was found to be higher by 62.1% and the weed dry weight higher by 27.3% compared to these parameters after the previous soybean crop. A richer floristic composition of weeds was also observed in the stand after winter rapeseed. Under conventional tillage conditions, compared to no-tillage, the number of weeds was found to be lower by 39.7% and their dry weight by 50.0%. An increase in the numbers of the dominant weed species was also noted in the untilled plots.

Highlights

Weed competitiveness in a wheat crop is determined by the number and diversity of weed species occurring in the crop
The average value for the 4-year study period was higher after the previous winter rapeseed crop by 62.1% relative to that found after soybean, whereas under no-tillage conditions it was higher by 65.9% compared to conventional tillage
Throughout the duration of the experiment, Viola arvensis and C. arvense were characterized by the highest constancy (Class V and IV) after all forecrops and tillage systems used, and in the case of Veronica arvensis after the winter rapeseed crop (Tab. 3)

Summary

Introduction

Weed competitiveness in a wheat crop is determined by the number and diversity of weed species occurring in the crop. It is estimated that about 150 species occur in cereal crops, out of which 50 can be considered as common [1]. In-crop weed infestation is affected by both habitat conditions and agronomic practices, including the forecrop and tillage treatments used [2,3,4,5]. Tillage carried out appropriately and timely is the basic method for reducing the number of weeds threatening crops. The reason for the abandonment of conventional ploughing is the destruction of the topsoil structure and reduced soil biological diversity [6,7]

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Discussion

Conclusion