Improving maize growth and development in relation to soil applied elemental sulfur

A field experiment was conducted to ascertain the effect of varying soil applied elemental sulfur (S) levels viz; 0, 10, 20, 30, 40 and 50 kg ha, on maize growth and development. Experiment was conducted in randomized complete block design (RCBD) with three replicates. Growth and development parameters were computed; included leaf area per plant LAI, LAD, CGR, NAR and TDM and experimental results revealed that increasing S levels were pragmatic in improving maize performance. However, soil applied elemental S @ 30 kg ha proved to be beneficial involved in growth and yield improvement. Maximum CGR (23.44 g m-2 d-1), NAR (6.23 g m-2 d-1) and LAI (4.85) was in plots where S was applied at 30 kg ha while least LAI (4.40), LAD (193.45 days), TDM (1178.13 kg ha) was in control treatment. Therefore, elemental S @ 30 kg ha was noted to be most suitable for sustainable maize production amongst all other treatments

Managing an Invasive Weed Species, Parthenium hysterophorus, with Suppressive Plant Species in Australian Grasslands

Parthenium weed has been invading native and managed Australian grasslands for almost 40 years. This study quantified the potential of selected plant mixtures to suppress the growth of parthenium weed and followed their response to grazing and their impact upon plant community diversity. The first mixture consisted of predominantly introduced species including Rhodes grass, Bisset bluegrass, butterfly pea and green panic. This mixture produced biomass rapidly and showed tolerance to weed species other than parthenium weed. However, the mixture was unable to suppress the growth of parthenium weed. The second mixture of predominantly native pasture species (including forest bluegrass, Queensland bluegrass, Buffel grass and siratro) produced biomass relatively slowly, but eventually reached the same biomass production as the first mixture 12 weeks after planting. This mixture suppressed parthenium weed re-establishment by 78% compared to the control treatment. Its tolerance to the invasion of other weed species and the maintenance of forage species evenness was also superior. The total diversity was five times higher for the mixture communities as compared to the plant community in the control treatment. Therefore, using the suppressive pasture mixtures may provide an improved sustainable management approach for parthenium weed in grasslands

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p<0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p<0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding

The Remarkable Journey of a Weed: Biology and Management of Annual Ryegrass (Lolium rigidum) in Conservation Cropping Systems of Australia

Annual ryegrass (Lolium rigidum Gaud.), traditionally utilised as a pasture species, has become the most problematic and difficult-to-control weed across grain production regions in Australia. Annual ryegrass has been favoured by the adoption of conservation tillage systems due to its genetic diversity, prolific seed production, widespread dispersal, flexible germination requirements and competitive growth habit. The widespread evolution of herbicide resistance in annual ryegrass has made its management within these systems extremely difficult. The negative impacts of this weed on grain production systems result in annual revenue losses exceeding $93 million (AUD) for Australian grain growers. No single method of management provides effective and enduring control hence the need of integrated weed management programs is widely accepted and practiced in Australian cropping. Although annual ryegrass is an extensively researched weed, a comprehensive review of the biology and management of this weed in conservation cropping systems has not been conducted. This review presents an up-to-date account of knowledge on the biology, ecology and management of annual ryegrass in an Australian context. This comprehensive account provides pragmatic information for further research and suitable management of annual ryegrass

Seed priming with sorghum water extract and benzyl amino purine along with surfactant improves germination metabolism and early seedling growth of wheat

The influence of seed priming with sorghum water extract (SWE) and benzyl amino purine (BAP) on germination metabolism and early seedling growth of wheat was evaluated in this study. For priming, wheat seeds were soaked in SWE (5%), BAP (5\ua0mg\ua0L) alone and mixed with nonionic surfactant Tween-80 (0.05%). All the seed priming treatments significantly (p\ua0≤\ua00.05) improved the germination metabolism and early seedling growth as compared with dry seeds. Seed priming with combination of SWE, BAP and Tween-80 was the most effective treatment in improving the final germination percentage (34%), number of tillers per pot (50%), fresh weight (32%), dry weight (63%), chlorophyll contents (7%) and total phenolic contents (36%) over dry seed control. Similarly, maximum total soluble proteins, total soluble sugars and α-amylase activity were observed from the combined priming with SWE, BAP and Tween-80. Total soluble proteins were maximum in growing seedlings followed by germinating seeds than primed seeds. The germination and growth improvement by priming with SWE was comparable to BAP which makes it a cost-effective natural growth regulator. Combined applications are more effective, which may be due to enzymatic regulation in a synergistic manner

Management of Rottboellia cochinchinensis and other weeds through sequential application of herbicides in dry direct-seeded rice in the Philippines

Dry direct-seeded rice (DSR) systems are becoming popular due to resource conservation and economic returns but high weed pressure limits rice productivity. Rottboellia cochinchinensis (Lour.) W. D. Clayton is an emerging noxious weed of DSR and requires a suitable herbicide package for effective control. A field study was conducted to evaluate the efficacy of two pre-emergence (oxadiazon and pendimethalin) and two post-emergence (cyhalofop and bentazon) herbicides used in various combinations and sequences during two consecutive seasons (dry season, 2013-14 and wet season, 2014) at the International Rice Research Institute (IRRI), Los Baños, Philippines. Experiments were laid out in a randomised complete block design with three replications. Weedy plots were kept as control. All the herbicide treatments significantly reduced density and biomass of R. cochinchinensis and other dominating weeds at the flowering stage of rice during both seasons. The best treatment was pendimethalin followed by bentazon + cyhalofop, which caused 88-91% reductions in R. cochinchinensis density over the weedy control (9.4-13.0 plants m) during both seasons. It also reduced R. cochinchinensis biomass by 98-99% over the weedy control (331-344 g m). Different herbicide sequential treatments also controlled density and biomass of Cyperus rotundus L., Eclipta prostrata L., Echinochloa colona (L.) Link, and Murdannia nudiflora (L.) Brenan over the weedy control. Highest reductions in total weed density (82-84%) and total weed biomass (95-97%) over the weedy control were observed from pendimethalin followed by bentazon + cyhalofop applications during both seasons. All the herbicide treatments increased rice grain yield significantly over the control. The maximum grain yield was obtained from pendimethalin followed by bentazon + cyhalofop applications, which was 4.7 and 3.0 t ha during the dry season, 2013-14 and the wet season, 2014, respectively. The results suggest that the pre-emergence application of pendimethalin followed by the combination of post-emergence herbicides (bentazon and cyhalofop) may control R. cochinchinensis and other noxious weeds in DSR effectively with subsequent increment in rice grain yield

Seed priming with sorghum extracts and benzyl aminopurine improves the tolerance against salt stress in wheat (Triticum aestivum L.)

Salt stress impedes the productivity of wheat (L.) in many parts of the world. This study evaluated the potential role of benzyl aminopurine (BAP) and sorghum water extract (SWE) in improving the wheat performance under saline conditions. Seeds were primed with BAP (5\ua0mg\ua0L), SWE (5% v/v), BAP\ua0+\ua0SWE, and distilled water (hydropriming). Soil filled pots maintained at the soil salinity levels of 4 and 10\ua0dS\ua0mwere used for the sowing of primed and non-primed seeds. Salt stress suppressed the wheat growth; seed priming treatments significantly improved the wheat growth under optimal and suboptimal conditions. Total phenolics, total soluble sugars and proteins, α-amylase activity, chlorophyll contents, and tissue potassium ion (K) contents were increased by seed priming under salt stress; while, tissue sodium ion (Na) contents were decreased. Seed priming with SWE\ua0+\ua0BAP was the most effective in this regard. Under salt stress, the tissue Nacontents were reduced by 5.78, 28.3, 32.2, 36.7% by hydropriming, seed priming with SWE, seed priming with BAP, and seed priming with SWE\ua0+\ua0BAP, respectively over the non-primed control. Effectiveness of seed priming techniques followed the order SWE\ua0+\ua0BAP\ua0>\ua0BAP\ua0>\ua0SWE\ua0>\ua0Hydropriming. In conclusion, seed priming with SWE\ua0+\ua0BAP may be opted to improve the tolerance against salt stress in wheat

Weed management using crop competition in Australia

Adoption of conservation agriculture has brought significant changes in crop management in Australia. Increased reliance on herbicidal weed control is one of the most significant changes that have occurred throughout Australian cropping systems. The singular focus on herbicides for weed management has led to the frequent and widespread evolution of herbicide resistance in several weed species. Herbicide resistance means the loss of herbicide resources and as new herbicides modes of action are unlikely then use of alternative non-chemical cultural weed management options is essential. Crop competition is an approach that can be used to manage weeds for improved crop production. Enhanced crop competition can be achieved through the use of competitive crop species and cultivars, increased seed rates, narrow row spacing, and altered row orientation. These options are already routinely used in Australia and are proven in their ability to reduce weed biomass and fecundity. Although these strategies have been successfully used in Australian cropping systems, the research has frequently been focussed locally and not extrapolated more broadly throughout the Australian grain production region. Crop competition can potentially be a sustainable weed management option in reducing the reliance on herbicides and combating herbicide resistance and therefore, needs to be considered in all integrated weed management plans