Effect of conservation tillage and peat application on weed infestation on a clay soil

P Vanhala,L Pietola

doi:10.23986/afsci.5748

Abstract

Amendment of soil with peat is an attempt to avoid crop yield variation in the transition to conservation tillage, as it improves seedbed conditions and crop growth in drought-sensitive clay soils. Weed infestations were compared in 1999-2000 between the original and peat-amended clay (Typic Cryaquept, very fine, illitic or mixed) under different autumn tillage systems in an oats-barley rotation. In a field experiment, sphagnum peat (H = 4) had been spread (0.02 m 3 m -2 ) on the soil surface in August 1995. Tillage treatments included mouldboard ploughing (to 20 cm) and stubble cultivations of different working depths (8 or 15 cm) and intensity (once or twice). Weed biomass and density were assessed by an area of 1 m 2 per field plot in August 1999-2000 and June 2000. The 1999 season was dry, but soil moisture conditions were more favourable in 2000. Peat application tended to increase the number of volunteer oats and Chenopodium album in 1999, while decreasing Galium spurium biomass. Ploughing significantly increased the abundance of Chenopodium album and Lamium purpureum in barley (Hordeum vulgare) in 1999. Weed infestation was much lower in 2000, and tillage effect on Chenopodium album was minor in oats (Avena sativa). Growth of Lamium purpureum and Fumaria officinalis was stimulated in ploughed soils both years. Intensity and working depth of stubble cultivation had no significant effect on weeds.;

Highlights

Introduction years and different tillage systemsDuring the transition to conservation tillage the application of partly decayed organic material such as peat may help to maintain mineral soil productivity (Pietola and Tanni 2003)
Abundant data show that mouldboard ploughing leads to a relatively homogeneous distribution of seeds in the upper 15–25 cm of soil, while in shallow or no-tillage weed seeds tend to accumulate on or near the soil surface (e.g. Clements et al 1996)
Peat application had no significant effect on weed communities (Tables 2 and 3, Figs 1–4)

Summary

Introduction

During the transition to conservation tillage the application of partly decayed organic material such as peat may help to maintain mineral soil productivity (Pietola and Tanni 2003). Effect of tillage and peat on weed infestation. 1997) and weed plants (Skuterud et al 1996, Boström 1999) have been found to increase in unploughed soils, contrary findings exist; Tørresen (1998) reported the highest emergence rates in ploughing, intermediate rates in harrowing and the lowest rates in no-tillage. Reduced tillage seems to favour perennial and monocot weeds (Skuterud et al 1996). The infestation of couch grass (Elymus repens L.) in reduced tillage, especially in Nordic conditions, is often so severe that chemical control with glyphosate is needed (Pitkänen 1994). Abundant data show that mouldboard ploughing leads to a relatively homogeneous distribution of seeds in the upper 15–25 cm of soil, while in shallow or no-tillage weed seeds tend to accumulate on or near the soil surface (e.g. Clements et al 1996)

Methods

Discussion

Conclusion