Weed species diversity and shifts in conservation agriculture-based crop rotation systems on the Highveld area of South Africa

2021 ◽  
pp. 1-12
Author(s):  
Elbé Hugo ◽  
Maryke Craven ◽  
Andries A Nel
Keyword(s):  
South Africa ◽  
Species Diversity ◽  
Crop Rotation ◽  
Conservation Agriculture ◽  
Weed Species ◽  
And Shifts

Weed species diversity in spring barley varies with crop rotation and tillage, but not with nutrient source

Weed Science ◽  
1997 ◽  
Vol 45 (6) ◽  
pp. 798-806 ◽  
Author(s):  
F. Craig Stevenson ◽  
Anne Légère ◽  
Régis R. Simard ◽  
Denis A. Angers ◽  
Denis Pageau ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Crop Rotation ◽  
Spring Barley ◽  
Climatic Conditions ◽  
Dairy Manure ◽  
Weed Species ◽  
Nutrient Source ◽  
Weed Communities ◽  
Weed Species Richness

The development of sustainable farming systems depends on our ability to predict and manage the response of weed communities to changes in cropping practices. A study was established at Normandin, Québec, Canada, to investigate the influence of liquid dairy manure and mineral fertilizer, as well as chisel and moldboard plow tillage systems, in a spring barley monoculture and a 3-yr spring barley-forage rotation that included red clover and timothy. Weed species richness (Margalef's DMG), evenness (Shannon's E), and diversity (Shannon's H') were examined in these treatments from 1992 to 1995. Nutrient source had no effect on any of the three diversity indices. Evenness values were extremely low in all years, suggesting dominance of a few weed species in most treatments. Weed species richness and diversity generally were greater in the barley-forage rotation compared with the monoculture. Tillage effects on richness and diversity varied with crop rotation. Margalef's DMGand Shannon's H' were greater in 1993 and 1995, but they were lower in 1994 when chisel was compared with moldboard plowing in the monoculture. In 1994, chickweed density was about five times greater in the chisel-plowed monoculture compared with other treatment combinations of rotation and tillage. In 1995, only one species with a density of six plants m−2occurred in the moldboard-plowed monoculture compared with three to six species and densities of 51 to 832 plants m−2in the other rotation by tillage treatments. Climatic conditions and herbicide use patterns in the different crop rotation treatments may have contributed to the more dynamic nature of weed species diversity in the barley monoculture. Reduced frequency of tillage and herbicide application; management of the forage stands, especially with regard to their termination; and improved soil resource availability likely explained the increased but more stable diversity of the weed communities in the barley-forage rotation.

scholarly journals Diversity of segetal weeds in pea (Pisum sativum L.) depending on crops chosen for a crop rotation system

2014 ◽  
Vol 67 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Marta K. Kostrzewska ◽  
Magdalena Jastrzębska ◽  
Kinga Treder ◽  
Maria Wanic
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Crop Rotation ◽  
Spring Barley ◽  
Chenopodium Album ◽  
Research Station ◽  
Weed Species ◽  
Rotation System ◽  
Density And Biomass ◽  
Dominance Indices

<p>This study, lasting from 1999 to 2006, was conducted at the Research Station in Tomaszkowo, which belongs to the University of Warmia and Mazury in Olsztyn. The experiment was set up on brown rusty soil classified as good rye complex 5 in the Polish soil valuation system. The analysis comprised weeds in fields sown with pea cultivated in two four-field crop rotation systems with a different first crop: A. potato – spring barley – pea – spring barley; B. mixture of spring barley with pea – spring barley – pea – spring barley. Every year, at the 2–3 true leaf stage of pea, the species composition and density of individual weed species were determined; in addition, before harvesting the main crop, the dry matter of weeds was weighed. The results were used to analyze the constancy of weed taxa, species diversity, and the evenness and dominance indices, to determine the relationships between all biological indicators analyzed and weather conditions, and to calculate the indices of similarity, in terms of species composition, density and biomass of weeds, between the crop rotations compared.</p><p>The species richness, density and biomass of weeds in fields with field pea were not differentiated by the choice of the initial crop in a given rotation system. In the spring, the total number of identified taxa was 28 and it increased to 36 before the harvest of pea plants. <em>Chenopodium album </em>and <em>Echinochloa crus-galli</em> were the most numerous<em>.</em> <em>Chenopodium album, Echinochloa crus-galli, Sonchus arvensis</em>, <em>Fallopia convolvulus </em>and<em> Viola arvensis </em>were constant in all treatments, regardless of what the first crop in rotation was or when the observations were made.</p><p>The species diversity and the evenness and species dominance indices varied significantly between years and dates of observations. Species diversity calculated on the basis of the density of weed species was higher in the rotation with a mixture of cereals and legumes, while that calculated on the basis of weed biomass was higher in the system with potato. The similarity indices, which express the convergence of floristic composition as well as of the density and biomass of weeds growing in pea fields in the two crop rotation systems compared, were within a broad range (42–86%). The biodiversity of weed communities was more closely correlated to total precipitation than to air temperature.</p>

scholarly journals Effects of selective herbicide treatment on weed community in cereal crop rotation

2018 ◽  
Vol 64 (No. 9) ◽  
pp. 413-420 ◽  
Author(s):  
Mayerová Markéta ◽  
Mikulka Jan ◽  
Soukup Josef
Keyword(s):  
Species Diversity ◽  
Crop Rotation ◽  
Significant Treatment Effect ◽  
Cereal Crop ◽  
Weed Species ◽  
Significant Treatment ◽  
Alopecurus Myosuroides ◽  
Shannon’S Index ◽  
Herbicide Treatments ◽  
Annual Grasses

The efficacy of different frequently used selective herbicides and their impact on weed community were assessed in the field experiment with cereal crop rotation in 2013–2016. All herbicide treatments provided effective weed control, but community composition changed after 4 years. The density of many weed species increased on the untreated plots. Annual grasses Apera spica-venti and Alopecurus myosuroides had temporal increase at plots treated with 2,4-d, florasulam and aminopyralid, but decline at plots treated with pyroxsulam and/or chlorsulfuron. Significant treatment effect was confirmed only for Shannon’s index (H’), where the highest H’ was found in untreated controls (1.83) and the smallest in plots treated with 2,4-d + florasulam + aminopyralid (1.61). The pyroxsulam + florasulam + aminopyralid showed the greatest efficacy on a broad spectrum of weeds while maintaining reasonable species diversity.  

scholarly journals Promotion of weed species diversity and reduction of weed seedbanks with conservation tillage and crop rotation

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Stephen D. Murphy ◽  
David R. Clements ◽  
Svenja Belaoussoff ◽  
Peter G. Kevan ◽  
Clarence J. Swanton
Keyword(s):  
Species Diversity ◽  
Crop Rotation ◽  
Weed Management ◽  
Crop Yields ◽  
Conservation Tillage ◽  
No Tillage ◽  
Weed Species ◽  
Tillage Systems ◽  
Weed Density ◽  
Chisel Plow

In a 6-yr study on four farms (36 fields) in Ontario, Canada, we tested the effects of tillage (moldboard, chisel plow, no tillage) and crop rotations (continuous corn, corn-soybean, corn-soybean-winter wheat) on emerged and seedbank weed species diversity and density. Aside from the imposed experimental treatments, all other management was generally consistent among farms. Tillage had the largest effect on weed diversity and density. No tillage promoted the highest weed species diversity, chisel plow was intermediate, and moldboard plow resulted in the lowest species diversity. These results are consistent with ecological succession theory. The increase in weed species diversity resulted from 20 species being associated with no tillage systems, 15 of which were winter annuals, biennials, or perennials. Emerged weed density was affected only by tillage. Over 6 yr, seedbank declined in no-tillage systems from 41,000 to 8,000 seeds m−3. Crop yields were not affected by tillage or crop rotation. In practical terms, reduced tillage in combination with a good crop rotation may reduce weed density and expenditures on weed management.

Flat-cutting loosening in the system of fallow cultivation of chernozem soil and weediness of crops

2017 ◽  
Vol 1 (92) ◽  
pp. 78-84
Author(s):  
G. Koval ◽  
M. Kaliyevskiy ◽  
V. Yeshchenko ◽  
I. Martyniuk ◽  
N. Martyniuk
Keyword(s):  
Species Composition ◽  
Crop Rotation ◽  
Field Experiments ◽  
Early Spring ◽  
Weed Species ◽  
Wild Mustard ◽  
Spring Crop ◽  
White Campion ◽  
Investigation Methods ◽  
Top Soil

The article presents the results of field experiments, where on the basis of podsolized heavy loamy chernozem the influence of replacement of mouldboard ploughing with nonmouldboard cultivation over top soil weediness, weediness at the beginning and end of spring crop vegetation and weed species composition before harve sting were studied. Investigation methods of main fall ploughing under spring crops of five-course rotation: soybeans–rape–wheat–flax–barley at the depths of 15-17, 20-22, 25-27 cm were conducted after post-harvest field tillage. Analysis of data on contamination of the top soil with weed seeds have shown that with the replacement of fall main mouldboard ploughing gwith nonmouldboard cultivation the figure before sowing of all crops withdifferent tillage depthat crop rotation average increased by 131-132%. It caused the increase of actual weed infestation of all crops and at the beginning and end of spring crop vegetationafter different depths of fall nonmouldboard cultivation compared with ploughing at crop rotation average it was 120–132 and 123-138%respectively. Species composition of weeds afterthe replacement of main fall mouldboard ploughing with nonmouldboard cultivation remained mainlyunchanged; although in rape plantings the proportion of white campion and early spring weed sincreased, in wheat plantings– wild mustard andscentless mayweed, insoybean plantings– late spring weeds, in flax plantings– white campion, and in barley plantings– scarlet pimpernel.

ROLE OF CONSERVATION AGRICULTURE IN IMPROVING PRODUCTION WATER AND NITROGEN EFFICIENCY OF WHEAT UNDER RAINFED CONDITIONS

2020 ◽  
Vol 51 (4) ◽  
pp. 1139-1148
Author(s):  
Othman & et al.
Keyword(s):  
Crop Rotation ◽  
Nitrogen Use Efficiency ◽  
Agricultural Research ◽  
Research Work ◽  
Conservation Agriculture ◽  
Nitrogen Efficiency ◽  
Research Station ◽  
Wheat Varieties ◽  
Nitrogen Use ◽  
Use Efficiency

The research work was conducted in Izra’a Research station, which affiliated to the General Commission for Scientific Agricultural Research (GCSAR), during the growing seasons (2016 – 2017; 2017 – 2018), in order to evaluate the response of two durum wheat verities (Douma3 and Cham5) and two bread wheat varieties (Douma4 and Cham6) to Conservation Agriculture (CA) as a full package compared with Conventional Tillage system (CT) under rainfed condition using lentils (Variety Edleb3) in the applied crop rotation. The experiment was laid according to split-split RCBD with three replications. The average of biological yield, grain yield,  rainwater use efficiency and nitrogen use efficiency was significantly higher during the first growing season, under conservation agriculture in the presence of crop rotation, in the variety Douma3 (7466 kg. ha-1, and 4162kg. ha-1, 19.006 kg ha-1 mm-1,  39.62 kg N m-2respectively). The two varieties Douma3 and Cham6 are considered more responsive to conservation agriculture system in the southern region of Syria, because they recorded the highest grain yields (2561, 2385 kg ha-1 respectively) compared with the other studied varieties (Cham5 and Douma4) (1951 and 1724 kg ha-1 respectively). They also exhibited the highest values of both rainwater and nitrogen use efficiency.

scholarly journals The crucial role of mulch to enhance the stability and resilience of cropping systems in southern Africa

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Blessing Mhlanga ◽  
Laura Ercoli ◽  
Elisa Pellegrino ◽  
Andrea Onofri ◽  
Christian Thierfelder
Keyword(s):  
Crop Rotation ◽  
Southern Africa ◽  
Cropping Systems ◽  
Conservation Agriculture ◽  
Conventional Tillage ◽  
Yield Stability ◽  
No Tillage ◽  
The Stability ◽  
Stability And Resilience

AbstractConservation agriculture has been promoted to sustainably intensify food production in smallholder farming systems in southern Africa. However, farmers have rarely fully implemented all its components, resulting in different combinations of no-tillage, crop rotation, and permanent soil cover being practiced, thus resulting in variable yield responses depending on climatic and soil conditions. Therefore, it is crucial to assess the effect of conservation agriculture components on yield stability. We hypothesized that the use of all three conservation agriculture components would perform the best, resulting in more stable production in all environments. We evaluated at, eight trial locations across southern Africa, how partial and full implementation of these components affected crop yield and yield stability compared with conventional tillage alone or combined with mulching and/or crop rotation. Grain yield and shoot biomass of maize and cowpea were recorded along with precipitation for 2 to 5 years. Across different environments, the addition of crop rotation and mulch to no-tillage increased maize grain by 6%, and the same practices added to conventional tillage led to 13% yield increase. Conversely, adding only mulch or crop rotation to no-tillage or conventional tillage led to lower or equal maize yield. Stability analyses based on Shukla’s index showed for the first time that the most stable systems are those in which mulch is added without crop rotation. Moreover, the highest yielding systems were the least stable. Finally, additive main effects and multiplicative interaction analysis allowed clarifying that mulch added to no-tillage gives stable yields on sandy soil with high rainfall. Similarly, mulch added to conventional tillage gives stable yield on sandy soil, but under low rainfall. This is the first study that highlighted the crucial role of mulch to enhance the stability and resilience of cropping systems in southern Africa, supporting their adaptability to climate change.

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