The influence of primary soil tillage on soil weed seed bank and weed incidence in a cereal-grass crop rotation

Abstract

A field experiment was carried out at Vėžaičiai Branch of Lithuanian Research Centre for Agriculture and Forestry during the period 2008-2011. The study was aimed to determine the effects of various soil tillage methods: deep ploughing (20-25 cm), shallow ploughing (10-12 cm), shallow ploughless tillage (8-10 cm) and soil fertility improvement measures (plant residues, plant residues + straw, green manure 1 st cut + straw, green manure 2 nd cut + straw, farmyard manure 40 t ha -1 + straw) on the soil weed seed bank and weed incidence in a cereal-grass crop rotation. The soil of the experimental site is Dystric-Epihypogleyic Albeluvisol (ABg-p-w-dy) with a texture of sandy loam. In all experimental years, primary soil tillage had a significant influence on weed incidence in the crops of the rotation and on soil weed seed bank. The greatest amount of weeds, both in numbers and dry mass, in the crops of winter triticale and spring rape was determined in the shallow ploughless tillage treatment, in the crops of spring barley in the shallow ploughing treatment, and in the sward of red clover in deep and shallow ploughing treatments. All soil fertility improvement measures and their interaction with soil tillage methods did not have any substantial influence on the weed incidence in the rotation crops. The soil weed seed bank was 1.5 and 2.2 times greater in the shallow ploughing and shallow ploughless tillage treatments, compared with the conventional tillage treatment (deep ploughing). The influence of soil tillage methods manifested itself not only directly, but also through its interaction with soil fertility improvement measures. Regardless of the chosen soil fertility improvement measure, in all the treatments of shallow ploughless tillage, the soil weed seed bank was significantly greater, compared with the conventional soil tillage treatments. In the shallow ploughing and shallow ploughless tillage treatments there were found 25.5% and 41.5% more weed seed species in the soil, compared with the conventional tillage treatment. The seeds of Chenopodium album L., Persicaria lapathifolia L., Fallopia convolvulus L. and Viola arvensis Murray were found in all tillage treatments. The distribution of F. convolvulus L., P. lapathifolia L. seeds was significantly influenced by soil tillage only, that of V. arvensis Murray by soil tillage and its interaction with soil fertility improvement measures, and that of Ch. album L. by soil fertility improvement measures only.

The Effect of Different Soil Tillage Systems and Crop Residues on the Composition of Weed Communities

“…In our experiment, shallowly incorporating white mustard (as a green manure) encouraged the spread of weeds of wet, nitrogen-rich and very nitrogen-rich soils. Previous research has shown that reduced tillage increases the incidence of the weed species of nitrogen-rich and very rich soils (Cirsium arvense L., Elytrygia repens L., Poa annua L., Stellaria media (L.) Vill., Tripleurospermum perforatum (Mérat) M. Laínz) in spring and winter cereal crops [24,25]. Studies carried out in Lithuania show that in the direct drilling system, the total density of weeds before herbicide application was 21.0% higher and before harvesting was 42.0% higher when compared with conventional ploughing [26].…”

Changes in weed seed bank and flora as affected by soil tillage systems

“…Analysis of the size and composition of the weed seedbank in the soil can provide information on the past and present weed populations and forecast any future weed problems (Auffret, Cousins, 2011). Changes in the soil weed seed reserves depend on soil tillage, crop rotation, and weed control (Auškalnienė, Auškalnis, 2009;Skuodienė et al, 2013). Weed community composition in the surface (0-15 cm) layer seems more influenced by tillage system than by crop rotation (Barberi, Lo Cascio, 2001).…”

The influence of primary soil tillage, deep loosening and organic fertilizers on weed incidence in crops

“…In slightly acidic West Lithuania's Dystric Albeluvisol with low content of organic matter, primary soil tillage had a significant impact on the weed incidence in the crops of the rotation. The highest number of weeds and their dry mass in winter wheat and spring rape stands was determined by applying shallow ploughless tillage, in spring barley -shallow ploughing and in the sward of red clover -deep and shallow ploughing (Skuodienė et al, 2013). Assessing the primary ploughless soil tillage influence on the weed incidence in crops in West Lithuania's weatherbeaten soils it was determined that it had the greatest impact on perennial weeds whose population changes were more consistent than those of the annual weeds because of reduced soil tillage.…”