Impact of Agronomic Practices on Weed Communities: Tillage Systems

Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 409-417 ◽  
Author(s):  
Douglas A. Derksen ◽  
Guy P. Lafond ◽  
A. Gordon Thomas ◽  
Heather A. Loeppky ◽  
Clarence J. Swanton

Adverse changes in weed communities are a limiting factor for the adoption of conservation tillage practices. Predictions of an increased association of annual and perennial grasses, perennial dicot weeds, wind-disseminated species, and volunteer crops as weeds, and decreased association of annual dicot weeds in reduced-tillage systems were tested. Field experiments involving zero-, minimum-, and conventional-tillage systems were conducted in Saskatchewan from 1986 to 1990 at Ituna and Waldron, and from 1986 to 1988 at Tadmore. Weed community composition was analyzed for years 1988 to 1990 by canonical discriminant analysis. An increased association of perennial and annual grasses with zero tillage did not generally occur. Wind-dispersed species and volunteer crops were associated with reduced tillage and summer annual dicots with conventional tillage, but exceptions occurred. Species responded differently among sites or within a site over time. Within the time frame of this research, changes in weed communities were influenced more by location and year than by tillage systems, indicating fluctuational rather than directional or consistent changes in community composition.

Weed Science ◽  
1994 ◽  
Vol 42 (2) ◽  
pp. 184-194 ◽  
Author(s):  
Douglas A. Derksen ◽  
A. Gordon Thomas ◽  
Guy P. Lafond ◽  
Heather A. Loeppky ◽  
Clarence J. Swanton

Continuous-cropping conservation tillage systems may provide a viable alternative to the practice of summer fallow; however, concerns have been raised regarding potentially negative changes in weed communities in continuous cropping. Field experiments were established in Saskatchewan at three locations to determine the nature of weed community differences between a crop sequence with and without fallow in zero-, minimum-, and conventional-tillage systems from 1986 to 1990. Weed communities in continuous-cropping treatments tended to have greater total densities and were more similar in composition than crop-fallow treatments. Inclusion or exclusion of fallow within the rotation had a greater impact on weed community composition than did tillage system at Ituna and Waldron, but the reverse was true at Tadmore due to poor crop growth in all tillage systems. Differences in weed community composition were generally characterized by fluctuational changes in species associations. Volunteers of summer-annual crops, such as canola, flax, and barley, were associated with continuous cropping, but other species including perennial weeds, such as Canada thistle, perennial sowthistle, and quackgrass, were not strongly associated with the presence or absence of fallow. The practice of fallowing land to manage weeds may not be necessary.


Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 332-337 ◽  
Author(s):  
David L. Jordan ◽  
Patrick K. Bollich ◽  
Michael P. Braverman ◽  
Dearl E. Sanders

Field experiments were conducted from 1994 through 1996 in dry-seeded and water-seededOryza sativato compare weed control andO. sativayield in conventional tillage and reduced tillage (stale seedbed andTriticum aestivumcover crop) systems with no in-season herbicide, propanil applied early postemergence (EPOST), and propanil EPOST followed by propanil plus molinate (dry-seeded production) or granular molinate (water-seeded production). TheT. aestivumcover crop reducedEchinochloa crus-galli, Heteranthera limosa, Ammania coccinea, andCyperus esculentusinfestation and reduced the need for in-season herbicides in some but not all experiments.Oryza sativagrain yield was affected by both tillage systems and herbicide programs; however, these treatment factors influenced yield independently. Increasing the number of in-season herbicide applications increased weed control andO. sativayield in some but not all experiments.


1994 ◽  
Vol 74 (3) ◽  
pp. 421-428 ◽  
Author(s):  
Anne Légère ◽  
Régis R. Simard ◽  
Claude Lapierre

Soils under permanent pasture in eastern Canada are often characterized by acidic conditions and low P availability. A 3-yr experiment was initiated in the spring of 1988 to evaluate the feasibility of using conservation tillage practices and fertilization to improve the fertility of old, poorly managed pastures taken into cereals. The effects of tillage, liming and P additions on weed communities and spring barley (Hordeum vulgare L.) yields were measured on a Joseph sandy loam (Humic Gleysol). The tillage systems were 1) moldboard plowing in the fall, with disc harrowing in the spring; 2) chisel plowing in the fall, with disc harrowing in the spring; and 3) minimum spring surface tillage. Liming and P applications favoured growth and yields of barley. Weeds competing with barley were unable to derive benefits from either liming or increased P availability, despite their potential capacity to respond positively to this nutrient. Increasing soil fertility was generally detrimental to weeds, but this effect decreased with a reduction in tillage intensity. Yield response to improved fertility also decreased as tillage intensity was reduced. Despite a fertility status comparable to that found in the moldboard-plow treatment, conditions in reduced-tillage systems were less conducive to the competitiveness of the crop and, thus, favoured the development of weed infestations, particularly under minimum tillage. Optimum crop management that can maximize the competitiveness of the crop needs to be applied if benefits of fertilization in reduced-tillage systems are to be fully realized. Key words: Conservation tillage, reduced tillage, minimum tillage, lime, phosphorus, weeds


Author(s):  
V. Dumych ◽  

The purpose of research: to improve the technology of growing flax in the Western region of Ukraine on the basis of the introduction of systems for minimizing tillage, which will increase the yield of trusts and seeds. Research methods: field, laboratory, visual and comparative calculation method. Research results: Field experiments included the study of three tillage systems (traditional, canning and mulching) and determining their impact on growth and development and yields of trusts and flax seeds. The traditional tillage system included the following operations: plowing with a reversible plow to a depth of 27 cm, cultivation with simultaneous harrowing and pre-sowing tillage. The conservation system is based on deep shelfless loosening of the soil and provided for chiseling to a depth of 40 cm, disking to a depth of 15 cm, cultivation with simultaneous harrowing, pre-sowing tillage. During the implementation of the mulching system, disking to a depth of 15 cm, cultivation with simultaneous harrowing and pre-sowing tillage with a combined unit was carried out. Tillage implements and machines were used to perform tillage operations: disc harrow BDVP-3,6, reversible plow PON-5/4, chisel PCh-3, cultivator KPSP-4, pre-sowing tillage unit LK-4. The SZ-3,6 ASTPA grain seeder was used for sowing long flax of the Kamenyar variety. Simultaneously with the sowing of flax seeds, local application of mineral fertilizers (nitroammophoska 2 c/ha) was carried out. The application of conservation tillage allows to obtain the yield of flax trust at the level of 3,5 t/ha, which is 0,4 t/ha (12.9 %) more than from the area of traditional tillage and 0,7 t/ha (25 %) in comparison with mulching. In the area with canning treatment, the seed yield was the highest and amounted to 0,64 t/ha. The difference between this option and traditional and mulching tillage reaches 0,06 t/ha (10,3 %) and 0.10 t/ha (18.5 %), respectively. Conclusions. Preservation tillage, which is based on shelf-free tillage to a depth of 40 cm and disking to a depth of 15 cm has a positive effect on plant growth and development, yield and quality of flax.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1276
Author(s):  
Vaida Steponavičienė ◽  
Aušra Marcinkevičienė ◽  
Lina Marija Butkevičienė ◽  
Lina Skinulienė ◽  
Vaclovas Bogužas

The composition of weed communities in agricultural crops is dependent on soil properties and the applied agronomic practices. The current study determined the effect of different tillage systems and crop residue on the soil weed community composition. The research programme encompassed 2013–2015 in a long-term field experiment located in the Experimental Station of Vytautas Magnus University in Lithuania. The soil type in the experimental field was qualified as Endocalcaric Stagnosol (Aric, Drainic, Ruptic, Amphisiltic). Weeds were categorised into communities according to soil pH, nitrogen and moisture indicators. The results of investigations were grouped using cluster analysis. Agricultural crops were dominated by different weed species depending on the soil pH and moisture. Weed species were relatively more frequent indicating nitrogen-rich and very nitrogen-rich soils. In the reduced tillage and no-tillage systems, an increase in the abundance of weed species indicating moderate acidity and low acidity, moderately wet and wet, nitrogen-rich and very nitrogen-rich soils was observed. The application of plant residues decreased the weed species abundance. In the reduced tillage and no-tillage systems, the quantitative distribution of weed was often uneven. By evaluating the association of weed communities with groups of different tillage systems with or without plant residues, their control can be optimised.


2021 ◽  
Vol 36 ◽  
pp. 03003
Author(s):  
Yakhiya Kaipov ◽  
Rifkat Akchurin ◽  
Rustam Kirayev ◽  
Asiya Nizaeva

Field experiments were conducted in the arid steppe zone of the Southern Urals, in the Republic of Bashkortostan of the Russian Federation. The soil is common chernozem. The precipitation during the growing season (May-September) is 166 mm. The experimental crop rotation consisted of 7 fields: 4 with perennial herbs (a mixture of Bromus inermis and Medicago varia), 3 with annual crops. The study analysed soil properties and carrying capacity in perennial grass rotation, conventional and reduced tillage. During the crop-pasture rotation, the humus content in the soil changes insignificantly depending on the tillage, being within 7.6-8.0 %. Perennial grasses loosened the soil, positively affecting moisture accumulation under crop rotation by the beginning of the pre-sowing period. The arable layer of common chernozem in the reduced tillage had a density of 1.05 g/cm3, less than 0.06 g/cm3 in conventional cultivation. Fertilizer application increased yields at 0.49-0.51 t/ha of feed units. Reduced tillage resulted in higher feed units by 0.06-0.08 tons per 1 ha. Crop-pasture rotation implementation and development ensures bioclimatically-determined yields of fodder crops and maintains soil fertility at an optimal level.


2013 ◽  
pp. 183-186
Author(s):  
Géza Tuba

he effect of reduced and conventional tillage systems on soil compaction and moisture content in two years with extreme weather conditions is introduced in this paper. The investigations were carried out in a long-term soil cultivation experiment set on a heavy textured meadow chernozem soil at the Karcag Research Institute. In 2010 the amount of precipitation during the vegetation period of winter wheat was 623.3 mm, 2.2 times higher than the 50-year average, while in 2011 this value was 188.7 mm giving only 65% of the average. The examinations were made after harvest on stubbles on 4 test plots in 5 replications in the case of each tillage system. Soil compaction was characterised by penetration resistance values, while the actual soil moisture contents were determined by gravimetry. The values of penetration resistance and soil moisture content of the cultivated soil layer were better in the case of reduced tillage under extreme precipitation conditions. It could be established that regular application of deep soil loosening is essential due to the formation of the unfavourable compact soil layer under 30 cm. Conventional tillage resulted in enhanced compaction under the depth of ploughing, the penetration resistance can reach the value of 4 MPa under wet, while even 8 MPa under dry soil status.


2006 ◽  
Vol 20 (1) ◽  
pp. 249-254 ◽  
Author(s):  
Ronald J. Levy ◽  
Jason A. Bond ◽  
Eric P. Webster ◽  
James L. Griffin ◽  
Steven D. Linscombe

Field research was conducted for 3 yr to evaluate crop response and weed control under conventional and reduced tillage in drill- and water-seeded imidazolinone-tolerant (IT) rice culture. Imazethapyr was applied at 70 g ai/ha PRE followed by (fb) imazethapyr at 70 g/ha applied POST to three- to four-leaf rice or at 105 g/ha PRE fb 70 g/ha POST. In both conventional and reduced tillage systems, imazethapyr applied PRE fb POST at 70 g ai/ha controlled red rice, barnyardgrass, Amazon sprangletop, and rice flatsedge 87 to 99% 35 d after POST treatment (DAT). At 35 DAT, Indian jointvetch control with sequential applications of imazethapyr was as high as 70% in water-seeded rice but no more than 54% in drill-seeded rice. Tillage, seeding method, and imazethapyr rate had no effect on days to 50% heading, seeds per panicle, seed weight per panicle, or percentage of seed harvest. However, a reduction of 27% in days to 50% heading, 80% in seeds per panicle, 84% in seed weight per panicle, and 100% in percentage seed harvest index occurred when imazethapyr was not applied because of weed interference. Culm number was reduced 28%, and culm weight 32% under reduced tillage compared with conventional tillage. With sequential applications of imazethapyr at 70 g/ha, rice yield was 63% greater when rice was water-seeded compared with drill-seeded. No differences in tillage systems for weed control, days to 50% heading, seed number, seed weight per panicle, percent seed, panicle height, lodging, or yield were observed. Results of these experiments demonstrate imazethapyr will effectively control weeds in both water- and drill-seeded rice and that reduced tillage can be used without negatively affecting rice production.


Weed Science ◽  
1989 ◽  
Vol 37 (2) ◽  
pp. 233-238 ◽  
Author(s):  
J. Anthony Mills ◽  
William W. Witt

Field experiments were conducted to evaluate the interactions of tillage systems with imazaquin and imazethapyr on weed control and soybean injury and yield. Control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail from imazaquin and imazethapyr in conventional tillage was generally equal to or greater than control in no-tillage. However, under limited rainfall, weed control in no-tillage was generally equal to or greater than control in conventional tillage. Reductions in soybean heights due to herbicide treatment were evident in both tillage systems in 1985 and 1986 but not in. Soybean yields were reduced in 1985 from imazaquin at 140, 210, and 250 g/ha and imazethapyr at 105 and 140 g/ha. Yields were not reduced in 1986 and. Imazaquin and imazethapyr appear to provide adequate control of jimsonweed, common cocklebur, ivyleaf morningglory, velvetleaf, and giant foxtail in conventional and no-till systems.


Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 67-73 ◽  
Author(s):  
J. Dorado ◽  
J. P. Del Monte ◽  
C. López-Fando

In a semiarid Mediterranean site in central Spain, field experiments were conducted on a Calcic Haploxeralf (noncalcic brown soil), which had been managed with three crop rotations and two tillage systems (no-tillage and conventional tillage) since 1987. The crop rotations consisted of barley→vetch, barley→sunflower, and a barley monoculture. The study took place in two growing seasons (1992–1994) to assess the effects of management practices on the weed seedbank. During this period, spring weed control was not carried out in winter crops. In the no-tillage system, there was a significant increase in the number of seeds of different weed species: anacyclus, common purslane, corn poppy, knotted hedge-parsley, mouse-ear cress, spring whitlowgrass, tumble pigweed, venus-comb, andVeronica triphyllos.Conversely, the presence of prostrate knotweed and wild radish was highest in plots under conventional tillage. These results suggest large differences in the weed seedbank as a consequence of different soil conditions among tillage systems, but also the necessity of spring weed control when a no-tillage system is used. With regard to crop rotations, the number of seeds of knotted hedge-parsley, mouse-ear cress, and spring whitlowgrass was greater in the plots under the barley→vetch rotation. Common lambsquarters dominated in the plots under the barley→sunflower rotation, whereas venus-comb was the most frequent weed in the barley monoculture. Larger and more diverse weed populations developed in the barley→vetch rotation rather than in the barley→sunflower rotation or the barley monoculture.


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