Cultural Weed Management

The study of weed germination can improve knowledge on their seasonal dynamics in fields and facilitate the design of ecologically sustainable management. An experiment was conducted to evaluate the e↵ect of a range of constant and alternate temperatures on the germination of Chloris barbata, Cynodon dactylon, and Cyperus rotundus collected in Angola. Interesting di↵erences were observed between the germination responses of the three species. No germination was observed for any species at 10 or 15-5 C. Chloris barbata quickly germinated at most constant and alternate incubation temperatures, showing low primary dormancy and high germinability. Fast and high germination was observed for Cynodon dactylon at most alternate temperatures, while lower germination percentages were achieved at constant temperatures, especially the highest ones. Cyperus rotundus achieved good germination percentage at alternate temperatures, even if with slower and more extended germination dynamics than the other species, while almost no seeds germinated at constant temperatures. This study improves our knowledge of germination ecology for these species and allows some control tools to be identified, such as soil tillage, cover crops, and living or dead mulches, which can contribute to their ecologically sustainable management.

Our language and metaphors about environmental issues reflect and affect how we perceive and manage them. Discourse on invasive species is dominated by aggressive language of aliens and invasion, which contributes to the use of warlike metaphors to promote combative control. This language has been criticised for undermining scientific objectivity, misleading discourse, and restricting how invasive species are perceived and managed. Calls have been made for alternative metaphors that open up new management possibilities and reconnect with a deeper conservation ethic. Here, we turn to Indigenous perspectives because they are increasingly recognised as offering important and novel voices in invasive species discourse. We examine how Australian Aboriginal elders and land managers (rangers) speak about 'environmental weeds' (the term used to describe invasive plants in Australia) and weed management. Based on qualitative research with five Aboriginal groups in the Kimberley region of Western Australia, our findings indicate that Aboriginal elders speak about weeds through passive, neutral language and prefer metaphors for weed management that focus on health, care and creation. We outline the influence that this language has for how rangers practice weed work and discuss its implications for the mainstream paradigm.

Weeds are currently present in a wide range of ecosystems worldwide. Although the beginning of their evolution is largely unknown, researchers assumed that they developed in tandem
with cultivation since the appearance of agricultural habitats some 12,000 years ago.
These rapidly-evolving plants invaded the human disturbed areas and thrived in the new habitat. Here we present unprecedented new findings of the presence of “proto-weeds” and small-scale trial cultivation in Ohalo II, a 23,000-year-old unter-gatherers' sedentary camp on the shore of the Sea of Galilee, Israel.We examined the plant remains retrieved from the site (ca. 150,000 specimens), placing particular emphasis on the search for evidence of plant cultivation by Ohalo II people and the presence of weed species. The archaeobotanically-rich plant assemblage demonstrates extensive human gathering of over 140 plant species and food preparation by grinding wild wheat and barley. Among these, we identified 13 well-known current weeds mixed with numerous seeds of wild emmer, barley, and oat.
This collection provides the earliest evidence of a human-disturbed environment—at least11 millennia before the onset of agriculture—that provided the conditions for the development of "proto-weeds", a prerequisite for weed evolution. Finally, we suggest that their presence indicates the earliest, small-scale attempt to cultivate wild cereals seen in the
archaeological record.

A B S T R A C T Weed flora has not been analyzed quite often from its phytosociological classification and ecological point of view due to its deteriorating impacts on economic crops. For the first time weed flora in winter wheat fields of the District Malakand, Pakistan were sampled and quantitatively analyzed to identify indicator weeds and weeds associations' formation, using robust multivariate statistical approaches. It was hypothesized that the variation in an agro-ecological system gives rise to diverse associations of weed species under the influence of edaphic and climatic factors and prevailing farming practices under micro and macro habitat. The quantitative ecological techniques i.e., quadrat along transect method were used to find various phytosociological attribute including Density, Frequency, Cover and Important Value Indices of weeds in the region. 1200 quadrates/releves were established for quantification of weed species in one hundred and twenty randomly selected wheat fields in a region of 26727 ha of wheat growing region. Data was put in MS Excel for analyses in the PCORD Version 5 to find out various weed associations and their specific indicator species. Using Cluster and Two Way Cluster Analyses via Sorenson distance measurements five major clusters/plant associations were established using 1,0 data. These species associations were: (1) Emix-Vicia-Lathyrus weed association, (2) Alysum-Cannabis-Lithospermum weed association, (3) Oxalis-Lathyrus-Chenopodium weed association, (4) Euphorbia-Cerastium-Capsella-bursa weed association and (5) Alopecurus-Mazus-Persicaria weed association. Association 1 includes 17 fields with a total of 170 releves (17 × 10) in the region. Association 2 includes 30 fields and 300 releves (30 × 10), association 3 has 15 fields and 150 releves (15 × 10), association 4 has 34 fields and 340 releves (34 × 10) and association 5 has 24 fields and 240 releves (24 × 10) in the study area. Various climatic factor, edaphic variables and farming practices associated in each field were also examined for comparisons of influencing factors of weed associations and recognition their respective indicator species. Temperature, soil pH, electrical conductivity, soil structure, soil organic matter, lime contents, preceding crops, use of herbicides, time and quantity of manure were the main factors/ingredients responsible for the variation and formation of different associations. Indicator species analysis gave the indicator weeds of each association under the influence of each determining variable. From findings of this research it is concluded that farming practices and edaphic factor show significant effects on recognition of Indicator species, distribution of weed flora and formation of weed associations/communities in the region. Understanding these phenomena could further be used for weeds management purposes under the micro climatic, edaphic and local farming practice regimes. Though the weeds are considered as unwanted plants, nevertheless some of the economically important and rarely distributed weeds also need proper conservation management.

Rice is an increasingly important commodity in sub-Saharan Africa. In Tanzania, the rice yield gap is as high as 87%, due to a combination of production constraints and sub-optimal crop management. Reducing this yield gap may be partly achieved through the introduction and dissemination of good agricultural practices (GAP). We conducted 18 farmer-managed on-farm trials in Tanzania, to test a set of GAP components against conventional farmers' practices (FP) for two consecutive growing seasons in 2013 and 2014. The objectives were: (1) to understand farmers' capabilities in implementing GAP; (2) to acquire better insights into the merits, relevance and suitability of individual GAP components; and (3) to provide a case study showing that exposure to good practices combined with the farmers' own experimentations can serve to improve and, trigger a positive change in the participating farmers' crop management. Compared to the farmers' own practices, average yield increases of 1 t paddy ha −1 in 2013 and 2.7 t ha −1 in 2014 were achieved when following GAP. These yield advantages were mainly obtained by a higher panicle number, improved harvest index and improved weed control. Farmers experienced difficulties with land levelling, planting or sowing in lines and using rotary weeders, but they were convinced that these technologies are important to boost their rice yields. The case of Tanzania shows that paddy yields can be substantially improved by GAP and that adoption of GAP by smallholder rice farmers can be triggered by stimulating experimentations with such practices on their own farms.

Wheat is the most planted crop as well as the most important food and the main crop in the rotations in Turkey. Wheat grows in all parts of the Turkey and Trakya region which is European part of Turkey exist at the 3 rd region after Middle and Southeastern Anatolia. Clearfield System which is developed by BASF with combination of IMI (Imidazolinone) herbicide and resistant varieties started firstly in corn, but currently IMI sunflower, canola, rice, wheat, etc. were cultivating by farmers widely in the world. In Turkey, Clearfield system exist only in sunflower and rice not in the wheat yet. IMI wheat could be good solution for proper weed control in especially some areas which were invaded by some perennial grassy weeds. TRAGEN Research Company which is in Trakya Technopark, Edirne, Turkey started first time in Turkey IMI resistant wheat cultivar breeding program. The study was conducted to test performance of some IMI type wheat cultivars in Trakya Region conditions in 2019-2020 growing season in Edirne and Tekirdağ Malkara locations. The experiments were conducted with four replications with five control wheat cultivars which are the most planted and preferred wheat cultivars in Trakya Region. The study results indicated that some IMI cultivars exhibited higher seed yield performances over control cultivars. The promising candidate IMI lines after evaluating quality and yield performances will be sent to registration trials then to produce in Turkish seed market.

By selecting for prostrate growth habit of the juvenile phase of the cycle, durum wheat cultivars could be developed with improved competitive ability against weeds, and better soil coverage to reduce the soil water lost by evaporation. A panel of 184 durum wheat (Triticum turgidum subsp. durum) genotypes, previously genotyped with DArT-seq markers, was used to perform association mapping analysis of prostrate/erect growth habit trait and to identify candidate genes. Phenotypic data of plant growth habit were recorded during three consecutive growing seasons (2014-2016), two different growth conditions (field trial and greenhouse) and two sowing periods (autumn and spring). Genome-wide association study revealed significant marker-trait associations, twelve of which were specific for a single environment/year, 4 consistent in two environments, and two MTAs for the LSmeans were identified across all environments, on chromosomes 2B and 5A. The co-localization of some MTAs identified in this study with known vernalization and photoperiod genes demonstrated that the sensitivity to vernalization and photoperiod response are actually not only key components of spring/winter growth habit, but they play also an important role in defining the magnitude of the tiller angle during the tillering stage. Many zinc-finger transcription factors, such as C2H2 or CCCH-domain zinc finger proteins, known to be involved in plant growth habit and in leaf angle regulation were found as among the most likely candidate genes. The highest numbers of candidate genes putatively related to the trait were found on chromosomes 3A, 4B, 5A and 6A. Moreover, a bioinformatic approach has been considered to search for functional ortholog genes in wheat by using the sequence of rice and barley tiller angle-related genes. The information generated could be used to improve the understanding of the mechanisms that regulate the prostrate/erect growth habit in wheat and the adaptive potential of durum wheat under resource-limited environmental conditions.

In order to determine the effect of mulch on some characteristics of potato, a factorial experiment based on
randomized complete block design with three replications was conducted in Asadabad, Hamedan (Iran). The experimental treatments consisted of mulch in five levels (clear mulch, white mulch, black mulch, double layer mulch and control, without mulch) and cultivar in two levels (Agria and Sante). The effect of mulch on the fresh and dry weight of weed was significant, so that the black and double layer mulches had greatest impact on
reducing the fresh and dry weight of weed, respectively. As compared to control, clear mulch treatments could reduce the period of tuber formation by 6.33 days. Double layer mulches showed the highest number of stolons at 60-day after planting. In comparison to the control, mulch could reduce the days to harvest, while the clear (104.83 days), double layer (105 days), and white (105.16 days) mulches all had significant differences when compared to the control (108.16 days). Cultivar Sante and double layer mulch also had the greatest impact on
early potato crop. Mulch was not, however, seen to have significant effect on yield per plant. Based on the overall
results, cultivar Sante and double layer mulch are suggested for the purpose of further study in Asadabad, Hamedan.