Journal of Sustainable Agriculture and Environment最新文献

Shifting from conventional to sustainable agriculture demands well-designed experiments and robust analytical models to evaluate agroecological system performance and resilience. We modelled aphid population dynamics in broccoli monocultures and broccoli-basil intercrops using spatio-temporal approaches, informed by laboratory experiments on aphid avoidance behaviour. These experiments compared conventional, intensive crop production with sustainable plant protection practices, such as the impact of intercropping on aphid population growth rates. The results revealed that aphids significantly avoided broccoli leaves intercropped with basil, preferring monoculture broccoli. The presence of basil significantly reduced aphid population growth rates, leading to population decline. These findings informed mathematical models integrating plant-herbivore interactions, aphid movement, diffusion, and repellency. The models employed deterministic approaches, including non-spatial coupled population dynamics and spatial (1D and 2D) reaction-diffusion frameworks, simulating aphid dispersal and plant-aphid interactions over 50 and 100 m domains. Numerical simulations demonstrated that aphids avoid broccoli intercropped with basil, with models capturing basil's repellent effect in a spatio-temporal context. Simulations revealed cyclic oscillations in plant and aphid populations, stabilising to a steady equilibrium due to spatial population coupling. The spatially explicit approach highlighted how population growth rates, diffusion coefficients, aphid mortality, and spatial domain size influence aphid movement and repellency. Higher diffusion coefficients and lower aphid mortality from other causes amplified the repellent effect of the intercrop system, significantly reducing aphid populations. Our results suggest that broccoli-basil intercropping enhances pest regulation, offering a sustainable alternative to chemical pest control, although aphid dispersal rates and spatial domain size significantly affect its efficacy.

Increasing awareness of the adverse effects of agrochemicals is driving farmers to adopt more sustainable strategies for enhancing plant growth. Biostimulants have gained significant attention in both academic research and the horticultural industry as promising tools to promote growth, improve stress tolerance, and enhance crop performance, while reducing environmental impacts. This study, conducted from March to July 2024, evaluated the effects of different experimental biostimulants (EBs) on the growth, development, and productivity of wild strawberry plants (Fragaria vesca L., cv. “Malga”) cultivated under greenhouse soilless conditions. Despite their diverse origins, all tested EBs were sustainably derived from circular economy processes: (i) a suspension of freeze-dried microalgae (Tetraselmis chuii) (MA), (ii) a suspension of a lyophilized microbial mixed culture of purple non-sulfur bacteria (PNSB), and (iii) a hydro-alcoholic extract of pulverized hop biomass (HE). The EBs were applied weekly to the substrate: MA and PNSB at concentrations of 5% and 10%, and HE at 15 and 30 mL/L. Morphological and physiological parameters were recorded weekly until plant uprooting, while biochemical analyses were performed on leaves and fruits at the end of the trial. Application of EBs significantly enhanced plant growth and yield. MA treatments resulted in the greatest plant height, antioxidant activity, and total phenolic content; PNSB promoted the highest total root length and both fresh and dry biomass; and HE at 30 mL/L produced the greatest fruit number per plant. These results underline the potential of biostimulants to optimize strawberry production in controlled environments and contribute to more sustainable agricultural practices.

The overuse of agrochemicals has created negative impacts on the environment and human health, raising the need for a sustainable approach to enhance crop productivity. Beneficial bacteria, known for promoting plant growth and health, are considered with significant potential. However, the distribution and community composition of potential plant-beneficial bacteria (PBB) across soil and plant compartments remain largely underexplored. In this study, we characterized the diversity, composition and habitat preferences of potential PBB communities across three compartments of tomatoes. The potential PBB community in rhizosphere soil exhibited the highest diversity and abundance, whereas phyllosphere samples showed the lowest richness. Actinobacteria and Rubrobacteria dominated the soil potential PBB community, while Actinobacteria and Bacilli were predominant in the phyllosphere. At the genus level, Rubrobacter, Blastococcus and Nocardioides were the most prevalent potential PBB. In functional groups, plant growth-promoting bacteria had the highest relative abundance across all compartments. Soil pH was identified as the most important factor driving the potential PBB diversity and community composition. This study enhances our understanding about the distribution and community structure of potential PBB and their plant-beneficial traits across plant-associated compartments and their responses to soil properties. New insights into potential PBB of tomatoes can serve as a crucial reference for the engineering of this beneficial bacterial community in improving plant disease control and plant performance in future.

Strawberry [Fragaria × ananassa (Weston) Rozier] cultivation is increasingly shifting toward soilless systems due to soilborne disease pressures and sustainability concerns. Peat, the traditional substrate of choice, faces ecological and economic challenges, driving the search for alternative materials. Biochar, a carbon-rich byproduct of biomass pyrolysis, offers benefits such as enhanced water retention and nutrient dynamics, while wood distillate (WD), a secondary pyrolysis product, functions as a biostimulant promoting plant growth and stress resilience. This study evaluated the effects of biochar (0, 2% and 4% wt/wt) and WD (0, 2.5 mL/L, 5 mL/L and 10 mL/L on the substrate and 3 mL on the leaves) on soilless strawberry cultivation. Biochar had minimal impact during early growth but improved plant height, root length, and leaf area at harvest, particularly at higher concentrations, while at lowest doses, fruit yield and most quality parameters were unaffected, with slight improvements in colour and soluble solids. WD treatments, especially at 2.5 and 5 mL/L, enhanced several morphological and physiological traits. While neither amendment significantly increased yield or bioactive compound accumulation, both demonstrated potential to improve plant vigour and fruit quality. These findings support the use of biochar and WD as sustainable inputs in resource-efficient, climate-resilient strawberry production systems.

Rising concern over unsustainable agricultural practices has spurred many farmers to adopt organic and eco-friendly practices. While numerous studies have compared conventional and eco-friendly farms in temperate regions, we still lack data from tropical regions, where the agricultural environment is very different (e.g., smaller farms with greater crop diversity). Thus, the objective of this study was to assess plant diversity in tropical smallholdings, comparing 13 eco-friendly and 13 conventional guava farms in central Thailand. We conducted plant surveys across all seasons and quantified plant diversity and floral resources for all wild (weedy) and cultivated plant species observed on study farms. We recorded 154 plant taxa from 51 families (73 wild taxa, 81 cultivated taxa). Wild plant diversity was significantly higher on eco-friendly than conventional farms (11.77 vs. 7.25 taxa, on average). In contrast, cultivated plant diversity did not differ between the two farm types (9.15 vs. 7.77 taxa). Plant diversity was highest during the rainy season, while floral richness and abundance did not differ across seasons. These findings reflect the agricultural practices of tropical smallholders, where crop diversification with both cash and subsistence crops is common, even in conventional farms. Importantly, the lack of herbicide use on eco-friendly farms promotes greater wild plant diversity, providing beneficial habitat and resources for pollinators, natural enemies of crop pests, and other local biodiversity.

This study explores the viability of in-situ recycling of hydroponic waste nutrient solutions using alkali treatment to produce micro-calcium phosphate. The recovered precipitate was converted into a usable liquid form (called Part C) and assessed for its effectiveness as a source of phosphorus, replacing 40% of the commercial Part B fertiliser in a hydroponic nutrient solution. The pilot study was conducted in a controlled greenhouse equipped with an automated fertigation system to ensure precise nutrient delivery and environmental control. Snow peas (Pisum sativum L.) were grown for 21 days using this nutrient solution, and its performance was compared with a control system employing commercial fertilisers. Results demonstrated that the test system, incorporating Part C, required 33% less commercial fertiliser while maintaining comparable plant growth, yield, and nutrient uptake. Except for a slightly lower chlorophyll content, plants in the test system exhibited no nutrient deficiencies; exhibited stable phosphorus, and enhanced calcium and magnesium uptake. Moreover, Part C contributed to improved pH and EC stability, reducing the need for frequent nutrient adjustments compared to the control. The economic analysis indicated a significant cost reduction without compromising plant health or productivity, highlighting the potential for broader application in sustainable hydroponic farming.

Climate change and associated extreme heat events threaten productivity in agricultural systems. Integrating trees into grazing/pasture systems has the potential to enhance resilience to warming. However, the extent to which tree cover can buffer the impacts of climate change on pasture species is unclear. We examined how tree density and spatial configuration influence leaf nitrogen content, specific leaf area, and photosynthetic heat tolerance (T_crit) of dominant pasture species in a temperate Australian landscape. Traits were assessed across fine-scale spatial gradients from individual trees under different structural configurations. Future thermal safety margins (TSMs) were projected under two climate emission scenarios—the best-case scenario (SSP1-2.6) and the worst-case scenario (SSP5-8.5) using 28 earth system models. While leaf nitrogen varied with tree spatial configuration, T_crit and TSMs remained largely conserved. Projected warming substantially reduced TSMs without exceeding thermal thresholds, suggesting limited physiological capacity for heat tolerance adjustment. These results highlight the constrained role of tree cover in buffering climate impacts on pasture species and the need for broader adaptation strategies in agricultural systems.