Search

This review examines the role of Pseudomonas spp. bacteria as biocontrol agents against crop diseases, focusing on their mechanisms of action, efficacy, and potential applications in sustainable agriculture. Pseudomonas spp., ubiquitous in soil ecosystems and root microbiomes, have attracted attention for their ability to suppress phytopathogens and enhance plant health through various mechanisms. These include direct competition for nutrients, production of antimicrobial compounds and volatile organic compounds, competition using type VI secretion systems, and indirect induction of systemic resistance. Our review shows that Pseudomonas strains effectively control a wide range of diseases across diverse plant species, with some strains demonstrating efficacy comparable to chemical fungicides. However, the review also highlights challenges in achieving consistent performance when using Pseudomonas inoculants under field conditions due to various biotic and abiotic factors. Strategies to optimize biocontrol potential, such as formulation techniques, application methods, and integration with other management practices, are discussed. The advantages of Pseudomonas -based biocontrol for sustainable agriculture include reduced reliance on chemical pesticides, enhanced crop productivity, and improved environmental sustainability. Future research directions should focus on understanding the complex interactions within the plant microbiome, optimizing delivery systems, and addressing regulatory hurdles for commercial deployment. This review underscores the significant potential of Pseudomonas spp. in sustainable crop protection while acknowledging the need for further research to fully harness their capabilities in agricultural systems. [ABSTRACT FROM AUTHOR]

Unprecedented plastic production has resulted in over six billion tons of harmful waste. Certain insect taxa emerge as potential agents of plastic biodegradation. Through a comprehensive manual and bibliometric literature analysis, this review analyses and consolidates the growing literature related to insect-mediated plastic breakdown. Over 23 insect species, representing Coleoptera, Lepidoptera, and 4 other orders, have been identified for their capacity to consume plastic polymers. Natural and synthetic polymers exhibit high-level similarities in molecular structure and properties. Thus, in conjunction with comparative genomics studies, we link plastic-degrading enzymatic capabilities observed in certain insects to the exaptation of endogenous enzymes originally evolved for digesting lignin, cellulose, beeswax, keratin and chitin from their native dietary substrates. Further clarification is necessary to distinguish mineralisation from physicochemical fragmentation and to differentiate microbiome-mediated degradation from direct enzymatic reactions by insects. A bibliometric analysis of the exponentially growing body of literature showed that leading research is emerging from China and the USA. Analogies between natural and synthetic polymer's degradation pathways will inform engineering robust enzymes for practical plastic bioremediation applications. By aggregating, analysing, and interpreting published insights, this review consolidates our mechanistic understanding of insects as a potential natural solution to the escalating plastic waste crisis. [ABSTRACT FROM AUTHOR]

Nitrogen (N) leaching from coarse-textured soils frequently leads to productivity losses and negative environmental consequences. Historically, clay amendment has been used on coarse-textured soils to decrease water repellence and nutrient leaching. More recently, biochar has been proposed as an alternative soil amendment to decrease N leaching while simultaneously storing carbon. As biochar has a greater nutrient-retention capacity, we hypothesised that biochar derived from Eucalyptus marginata would be a more effective amendment than clay at minimising N leaching. The soil used was a coarse-textured agricultural sand with the following treatments: (1) biochar incorporated homogenously into the 0-10 cm soil layer, (2) clay incorporated similarly, (3) biochar added as a layer at 10 cm depth, (4) clay added similarly, or (5) a control. Amendments were added at 25 t/ha and watered periodically over 21 days and watered with the equivalent to 30 mm. Clay and biochar amendments significantly decreased cumulative N[H.sub.4.sup.+] leaching by ~20% and N[O.sub.3.sup.-] leaching by 25%. Biochar decreased N[O.sub.3.sup.-] leaching significantly more than clay, possibly due to decreased nitrification. Dissolved organic N leaching was not influenced by any treatment. Leaching of N was unaffected by amendment application method. We conclude that to decrease N leaching, land managers should apply the most readily available of the amendments in the most convenient manner. Additional keywords: black carbon, charcoal, dissolved organic nitrogen, DON, mineralisation. Received 29 November 2011, accepted 29 March 2012, published online 25 May 2012, Introduction Improving soil fertility and productivity, while simultaneously decreasing negative environmental consequences is one of the greatest challenges in the management of agricultural and horticultural production systems. This is typically [...]

Estimation of soil organic carbon stocks requires bulk density (BD) measurements. Variability in BD contributes to carbon stock uncertainty, in turn affecting how large a change in stock can be observed over time or space. However, BD is difficult and time-consuming to measure, and sample collection is further complicated by extremely dry field conditions, coarse-textured soils, and high coarse-fragment content, which are common in southern Australia and other semi-arid and Mediterranean-type climates. Two alternatives to reduce BD sampling effort are to take fewer BD samples at a site (i.e. volumetric rings or clod), and to use more time-efficient methods (i.e. gamma-neutron density meter, NDM). We evaluate these options in the context of a soil carbon stock survey in agricultural land in the south-west of Australia. The BD values within a monitoring site measured with conventional and NDM methods were statistically different when assessed using large sample sizes; the measurements diverged where the coarse fraction volume was >20%. However, carbon stocks were equivalent, reflecting the much larger relative variability in carbon percentage, which contributed 84-99% of the uncertainty in carbon stocks compared with Additional keywords: carbon storage in soil, Mediterranean environments, variance component estimation., Introduction Soil carbon audits and monitoring activities are increasing across the globe for three major purposes: (1) climate, biogeochemical, and ecological modelling (Bellamy et al. 2005; Goidts and van Wesemael [...]