Caffeic Acid, an Allelochemical in Artemisia argyi, Inhibits Weed Growth via Suppression of Mitogen-Activated Protein Kinase Signaling Pathway and the Biosynthesis of Gibberellin and Phytoalexin

Artemisia argyi is widely distributed in Asia, and it often becomes the dominant population in the field because of its strong ecological niche competitiveness. Allelochemicals secreted by plants are generally considered an important reason for their dominance in ecological competition. In this study, the allelochemicals in A. argyi were screened by a series of experiments and their mechanisms were explored via transcriptomics. First, the inhibitory effects of A. argyi on Echinochloa crusgalli, Setaria viridis, Portulaca oleracea and Amaranthus retroflexus were evaluated. Then, we carried out a qualitative and quantitative analysis of the chemical composition of the aqueous extract of A. argyi to screen for potential allelochemicals that can inhibit weed growth. Four potential allelochemicals were quantified: neochlorogenic acid (5-CQA), chlorogenic acid (3-CQA), cryptochlorogenic acid (4-CQA), and caffeic acid (CA). Coincidentally, their allelopathic effects on weeds seemed to be identical to their content, in the order CA>4−CQA>5−CQA>3-CQA. These findings suggested that CA might be the main allelopathic compound in the aqueous extract of A. argyi. Subsequently, the allelopathic effect and molecular mechanism of CA on S. viridis leaves were investigated. The physiological results showed that CA significantly induced reactive oxygen species (ROS) production, led to malondialdehyde (MDA) accumulation, and disrupted enzyme activities (POD, SOD, CAT) in S. viridis leaves. Moreover, transcriptome results revealed that CA inhibited S. viridis growth by downregulating multiple genes involved in gibberellin (GA) and phytoalexin biosynthesis and Mitogen-activated protein kinase (MAPK) signaling pathways. In addition, differentially expressed genes (DEGs) related to the biosynthesis and signaling pathways of phytohormones were verified by Quantitative Real-Time PCR (RT-qPCR). Taken together, this study may be the first to identify allelochemicals and explore their molecular mechanism about A. argyi. Importantly, the ecological advantages of A. argyi could be applied to ecological regulation and the development of botanical herbicides.

Influence of Post Emergence Application of Herbicides on Growth, Yield and Economics of Dry Direct Sown Rice

The field trial was conducted on sandy clay loam soils of agricultural research station Ragolu, A.P. India during two consecutive Kharif seasons of 2015 and 2016 .The trial was conducted in Randomized Block Design with three replications and nine treatments Viz., T1- post emergence application of Bis-pyribac sodium @ 25 g ai/ha at 20 DAS fb Amine salt of 2,4 D @ 0.58 kg ai/ha at 40 DAS; T2- post emergence application of Bis-pyribac sodium @ 25 g ai/ha at 20 DAS fb metsulfuron methyl + chlorimuron ethyl (Almix) 4 g ai/ha at 40 DAS; T3- post émergence application Bis-pyribac sodium @ 25 g ai/ha at 20 DAS fb Ethoxysulfuron @ 20 g ai/ha at 40DAS ; T4- post emergence application Bis-pyribac sodium @ 25 g ai/ha at 20 DAS fb postemergence application of Fenoxaprop P ethyl with safenor (Rice star) @ 625ml/ha at 40 DAS ; T5- post emergence application Bis-pyribac sodium @ 25 g ai/ha at 20 DAS fb postemergence application of Cyhalofopbutyl @100 g ai/ha + amine salt of 2,4, D @ 0.58 kg ai/ha at 40 DAS; T6- post emergence application Bis-pyribac sodium @ 25 g ai/ha at 20 DAS fb Ethoxysulfuron @ 20 g ai/ha+ Fenoxaprop PEthyl with safenor (Rice star) @ 625ml/ha at 40 DAS; T7- Post emergece application of Penoxulam@ 25g ai/ha at 20 DAS fb amine salt of 2,4, D @ 0.58 kg ai/ha at 40 DAS ;T8- Two hand weedings at 20 & 40 DAS and T9- Weedy Check. The study in dry direct sown rice on weed management by herbicides revealed that, uncontrolled weed growth in dry direct sown rice reduced the grain yield by 46 to 54 percent. Post emergence application of Bis-pyribac sodium @ 25 g ai/ha at 20 DAS followed by Ethoxysulfuron @ 20 g ai/ha+ Fenoxaprop P Ethyl with safenor (Rice star) @ 625 ml/ha at 40 DAS resulted into taller plants, maximum number of tillers/m2, The highest dry matter production at harvest, more number of panicles/m2 filled grains/panicle, 1000 grain wt, higher grain yield (82-108 %t over weedy check) Straw yield besides higher gross returns net returns and B:C ratio among different herbicide treatments.

Effects of Cereal-Legume Intercropping and Mulching on Maize (Zea Mays L.) Productivity in Dry Season using Drip Irrigation in South-Sudanian Climatic Zone of Burkina Faso

The availability and sustainability of water in rural areas are significant challenges facing agricultural producers in the Sahelian zones. Maize-legume intercropping with a mulch cover for water conservation with drip irrigation is a promising production practice for conserving water, increasing productivity and improving soil health. A randomized complete block trial with 04 replications and 08 treatments was established in Sonsongona (11.2522°N, 4.4559°W), a village located west of Bobo-Dioulasso, Burkina Faso. Means separation by analysis of variance (ANOVA) was with RStudio 1.2.1335 software at the 5% threshold according to the Newman-Keuls test. The mulched treatments significantly affect soil moisture, maize growth, weed growth, and important maize yield attributes.

Efficacy, Energy Budgeting, and Carbon Footprints of Weed Management in Blackgram (Vigna mungo L.)

Weed management in blackgram is one of the most efficient ways to improve its yield, as uncontrolled weed growth causes a significant decrease in crop yield. A field experiment was performed at Berthin, Himachal Pradesh, India, to investigate the efficacy, energy use efficiency (EUE), and carbon footprints of weed management tactics. Twelve weed control treatments were tested applied alone or in combination at pre and post emergence stages. The most prominent weeds were Cyperus iria, Dactyloctenium aegyptium, and Echinochloa colona, which caused a 68.1% loss in unweeded conditions. The application of weed control treatments reduced the weed count at 60 DAS from around 50% to 90%. The most efficient weed control treatment was pre-emergence (PRE) use of ready mix imazethapyr 35% + imazamox 35% WG @ 80 g ha−1, which resulted in a minimum weed infestation (i.e., weed count and weed biomass) and consequently highest yield. Its efficacy in weed control treatment was on par with PRE use of ready mix imazethapyr (35%) + imazamox (35% WG @ 70 g ha−1. Maximum energy use efficiency was also obtained upon PRE use of imazethapyr (35%) + imazamox (35% WG) @ 80 g ha−1 (8.27), trailed by PRE use of imazethapyr + imazamox @ 70 g ha−1 (7.84), mainly because of the higher yield obtained in these treatments which shows their efficiency in energy conversion. The carbon footprints were observed to be the lowest in ready mix combination of imazethapyr (35%) + imazamox (35% WG) applied at 80 g ha−1 (0.11 kg CE kg−1 yield), followed by imazethapyr (35%) + imazamox (35% WG) applied at 70 g ha−1 (0.12 kg CE kg−1 yield), as it resulted in the lowest emission per unit output production.

Leaching Potential of Phosphite Fertilizer in Sandy Soils of the Southern Coastal Plain, USA

Novel biotechnology on transgenic plants capable of metabolizing phosphite (Phi), a reduced form of P, could improve the effectiveness of P fertilizers and reduce the P footprint in agriculture with the benefit of suppressing weed growth. However, potassium Phi (K-Phi) salts used as fertilizer are highly soluble in water. At the same time, sandy soils of the Southern Coastal Plain are vulnerable to leaching losses resulting from long-term Pi fertilizer application. We performed a replicated leaching trial using five soil materials that included three surface and two subsurface layers from cultivated topsoil (Ap horizon) with contrasting Phi and Pi sorption capacities. Each soil received three treatments K-Phi at rates 0 (control), 24, and 49 kg P ha−1 and leached twice with de-ionized water. All K-Phi-treated soils leached Phi except for the controls. A phosphorus saturation ratio (PSR) calculated from P, Al, and Fe in acid extracts indicated increasing environmental risk of Phi leaching in soils with lower Phi and Pi sorption capacities at rising rates of applied K-Phi. Because plants rapidly absorb Phi, further studies on the environmental impact of K-Phi fertilizer use should include the interaction of plants with soil properties and soil microbial activity at optimal Phi application rates for growing transgenic plants able to use Phi as a nutrient source.

Assessing Competitiveness of Fine Fescues (Festuca L. spp.) and Tall Fescue (Schedonorus arundinaceous (Schreb.) Dumort) Established with White Clover (Trifolium repens L., WC), Daisy (Bellis perennis L.) and Yarrow (Achillea millefolium L.)

Regulatory restrictions on herbicide use for managing turfgrass weeds has prompted the search for alternative control strategies. Fescue (Festuca) species were identified for their potential to interfere with growth of annual and perennial weeds. In a study conducted in 2018 and 2019, six fescue cultivars were tested from five different species for interference with the growth of three common turfgrass weeds: white clover (Trifolium repens L., WC), daisy (Bellis perennis L.) and yarrow (Achillea millefolium L.). Fine (Festuca L. spp.) and tall fescues (Schedonorus arundinaceus (Schreb.) Dumort.) were sown and grown in a field trial for 14 days before overseeding with different weeds. vigor and visual quality of grasses, weed cover, and vegetation cover was recorded regularly for 84 days. Differences in mean temperatures and precipitation between the two years of the study resulted in differences in growth of grasses and weeds, as well as in the extent of weed interference of fescue cultivars. Cultivars Musica (F. rubra L. ssp. commutata Gaudin) and Barpearl (F. rubra L. ssp. littoralis) were least affected by weed growth during both years, but there was overlap with other cultivars for the measured parameters. Melyane (tall fescue) was deemed unsuitable for natural weed suppression because growth and vigor declined after first mowing, ultimately leading to unacceptable visual quality. Turfgrass visual scores were moderately negatively correlated to weed cover in both years. Future research should focus on F. rubra L. ssp. rubra Gaudin and F. rubra L. ssp. littoralis subspecies and identify the mechanisms used to interfere with weed growth.

Effect of mulch on glyphosate mobility in soil column

Glyphosate is a broad-spectrum herbicide that often used in controlling weed growth in oil palm plantation. Glyphosate has a high polarity and solubility in water and is quickly absorbed by soil particles. Oil palm waste such as oil palm trunks (OPTs) and empty fruit bunches (EFBs) and the use of glyphosate in agricultural land can contribute to environmental pollution. Apart from the commercial mulch that often used in nurseries, mulch from OPT and EFB can be used to absorb glyphosate to prevent weed growth. The glyphosate concentration of soil and water samples was determined using High Performance Liquid Chromatography (HPLC). Two doses of glyphosate were used which are 5.5 mL/L (2255 mg a.i/L) and 11 mL/L (4510 mg a.i/L). Two water volumes are used which are 250 ml and 500 ml. Glyphosate residual concentration values was high in Serdang soil series at layer three while in Selangor soil series at layer one. The highest concentrations of glyphosate residues were 32.57 mg/L and 34.42 mg/L at Serdang and Selangor soil series respectively. Samples of soil in the mulch of EFB and OPT show low concentrations of glyphosate residue compared to commercial and non-mulching column. Results show that EFB and OPT indicate low residual concentration values at each layer in the soil column for both doses.

Design and Fabrication of Cost-Effective Agriculture Machine

Mulching has long been used to conserve soil moisture, manage weeds, modify soil temperature, and create a microclimate for plants. There are a variety of strategies for improving crop growing conditions, including increasing productivity and reducing the amount of water necessary to grow the crops. However, mulching paper, also known as agricultural film, is one of the most effective ways to cover the soil and keep the crop in the right environment This mulching paper comes in a varietyof varieties, but because plastic mulching is well-known for requiring less effort, we've chosen to work on an automatic mulching paper laying machine that also includes a drip laying attachment. Moisture in the soil is critical for crop survival in arid environments. Mulching with plastic paper film around theroot area of plants prevents weed growth while also storing water and preventing soil dehydration, however this method takes a lot of money and time. So the 'Mulching paper laying machine with hole punching' will save money and time because it will handle both chores at once, laying mulching paper and punching holes in the ground. A body, a mainframe with hoeing blades, hole punching wheels, drip role holder, and punching mechanism make up the plastic mulch laying machine. The mulch was laid on the prepared plantation bed by the machine in conjunction with the drip pipe. This will lay mulch onthe bed without destroying it, as well as punch the holes to the desired dimensions. The product might be used in agriculture to grow tomatoes, watermelons, muskmelons, and other hybrid varieties of crops. Bylowering the capital cost and time of laying the mulching paper using the most convenient way, as well as installing the drip irrigation pipe in one pass of the machine, it will be simple for the farmer. (Key words: agriculture, mulching paper, weed control)

Sole and Sequential Application of Herbicide and Straw Mulch on Weed Growth and Productivity of Direct Seeded Rainfed Rice (Oryza Sativa L.)

The sole and sequential application of herbicide and straw mulch on weed growth and productivity of rainfed direct seeded rice, were studied with 12 treatments during kharif 2019. Results showed that the application of oxadiargyl fb rice straw mulch @ 6 t/ha registered significantly the lowest weed density and dry weight at 60 DAS; however, it was statistically at par with oxadiargyl fb hand weeding. Weed free check produced the highest grain yield (3.05 t/ha) which was at par with the sequential application of oxadiargyl fb rice straw mulch @ 6 t/ha (2.99 t/ha) and oxadiargyl fb rice hand weeding (2.90 t/ha). Application of oxadiargyl fb rice straw mulch @ 6 t/ha fetched the maximum net return of Rs. 17528/- per ha and return per rupee invested of 1.52. Application of oxadiargyl fb rice straw mulch @ 6 t/ha could be recommended for managing complex weed flora, higher productivity and greater profit in rainfed direct seeded rice cultivation. Bangladesh J. Bot. 50(3): 671-677, 2021 (September)