The consequent influence of crop rotation and six-year-long spring barley monoculture on yields and weed infestation of white mustard and oats

Cezary Kwiatkowski

doi:10.5586/aa.2009.046

Abstract

The present study was conducted in the years 2007- 2008, after 6-year-long experiments in the cultivation of spring barley in a crop rotation system and in monoculture. The other experimental factor was the spring barley protection method. Intensive protection involved comprehensive treatment of barley (in-crop harrowing, seed dressing, application of herbicides, fungicides, a retardant and an insecticide). Extensive protection consisted only in in-crop harrowing, without the application of crop protection agents, except for seed dressing. The above mentioned factors formed the background for the study on the cultivation of white mustard and oats, as phytosanitary species, in successive years. In the test plants, no mineral fertilization and crop protection were applied. Such agricultural method enabled an objective assessment of the consequent effect of monoculture, crop rotation and crop treatments. A hypothesis was made that the cultivation of the phytosanitary plants in the stand after 6-year-long barley monoculture would allow obtaining the level of yields and weed infestation similar to those of the crop rotation treatments. It was also assumed that the cultivation of white mustard and oats would eliminate differences in plant productivity caused by the negative influence of extensive protection. It was proved that the cultivation of the phytosanitary plants eliminated the negative influence of monoculture on the level of their yields and weed infestation. However, the test plants did not compensate negative consequences of extensive protection. In spite of this, white mustard and oats effectively competed with weeds, and the number and weight of weeds in a crop canopy did not cause a dramatic decline in yields. In the test plant canopy, the following short-lived weeds were predominant: Chenopodium album, Galinsoga parviflora, Echinochloa crus-galli. The absence of herbicide application resulted in the compensation of perennial species: Elymus repens and Cirsium arvense.

Highlights

In crop rotations with large cereal proportions, in particular in monoculture, there occur a number of negative phenomena resulting, among other things, in a decline in competitiveness of crop plants relative to weed flora
The cultivation of this plant in the stand after spring barley under the Norfolk crop rotation system resulted in seed yield higher by 51% than that found in the treatments with the consequent influence of monoculture
The stand after spring barley grown in crop rotation and intensively protected guaranteed the largest white mustard seed yield (1.82 t ha-1)

Summary

Introduction

In crop rotations with large cereal proportions, in particular in monoculture, there occur a number of negative phenomena resulting, among other things, in a decline in competitiveness of crop plants relative to weed flora. Spring barley is a species sensitive to monoculture and related weed pressure (Wesołowski et al 2003; Blecharczyk et al 2005). Proper crop sequencing, based on environmental factors, coupled with appropriate agricultural practices applied with it, ensures to a large extent a successive increase in yields and a reduction in weed infestation (Zawiślak , 1997; Adamiak , 2007). In the opinion of some authors (Kwiatkowski , 2004a; Stupnicka - Rodzynkiewicz et al 2004), comprehensive mechanical and chemical protection of spring barley only partially compensates the effects of inappropriate crop sequencing. The cultivation of phytosanitary plants (mustard, oats) can be included among factors which reverse the negative effects of barley or wheat monoculture. In strongly cerealbased crop rotations, it may perform the role of a phytosanitary and regenerating plant (Jelinowski , 1979; Adamiak , 1992; Adamiak and Adamiak , 1994)

Objectives

Methods

Results

Conclusion