Deterring rodent seed‐predation using seed‐coating technologies

Activated carbon seed technologies: Innovative solutions to assist in the restoration and revegetation of invaded drylands

The demand for seed-based restoration and revegetation of degraded drylands has intensified with increased disturbance and climate change. Invasive plants often hinder the establishment of seeded species; thus, they are routinely controlled with herbicides. Herbicides used to control invasive plants may maintain soil activity and cause non-target damage to seeded species. Activated carbon (AC), which has a high adsorption of many herbicides, has been incorporated into seed pellets and coatings (seed technologies) to limit herbicide damage. Though various AC seed technologies have been examined in numerous laboratory and field studies, questions remain regarding their effectiveness and how to improve it, and what causes variation in results. We synthesized the literature on AC seed technologies for dryland restoration and revegetation to attempt to answer these questions. AC pellets compared to seed coatings were more thoroughly tested in the field and generally provide strong herbicide protection. However, greater amounts of AC in seed coatings appear to increase their effectiveness. Seed coatings show more potential for use than pellets because they are less logistically challenging to use compared to pellets, but need more field testing and refinement. Results often differ between laboratory and field studies, suggesting that field studies are critical in determining realized effects. However, seedling establishment failures from other barriers make it challenging to evaluate the effectiveness of AC seed technologies in the field. AC seed technologies are an innovative tool that with continued refinement, especially if other barriers to seedling establishment can be overcome, may improve the restoration and revegetation of degraded drylands.

Morphological Seed Traits Predict Early Performance of Native Species to Pelletized Seed Enhancement Technologies

Native seeds are a finite resource, and their inclusion in revegetation is vital for supporting restoration outcomes that are both effective and scalable. Pelletized seed enhancement technologies (SETs) offer a promising solution to improve seed use efficiency in ecological restoration. Yet, knowledge of how diverse suites of native species perform when pelletized is required to optimize the application of SETs to the many species and ecosystems where restoration is required. Using a greenhouse trial of 64 Australian plant species, we assessed species performance to pelleting by evaluating (1) overall species amenability to pelleting based on total emergence and survival and (2) how pelleting modifies the rate of emergence based on average time to emergence, emergence rate index, and time spread of emergence. We investigated the potential for using morphological seed traits (seed endosperm:seed ratio, seed length, seed area, and seed coat thickness) to predict performance outcomes, by identifying traits that may aid in the prediction of species amenability to pelleting and emergence speed when pelletized. We found that some species demonstrate high amenability to pelleting and that pelleting can modify the emergence rates for many species. This work advances our understanding of the applicability of SETs for diverse native species, demonstrating the application of such technologies for meeting ecological restoration goals.

Seed enhancement technologies for sustainable dryland restoration: Coating and scarification

High temperatures, soil salinity, a lack of available water, loose soils with reduced water holding, and low soil fertility are obstacles to restoration efforts in degraded drylands and desert ecosystems. Improved soil physical and chemical properties, seed germination and seedling recruitment, and plant growth are all proposed as outcomes of seed enhancement technologies (SETs). Seed priming, seed coating, and seed scarification are three SETs' methods for promoting seed germination and subsequent plant development under unfavorable environmental conditions. Various subtypes can be further classified within these three broad groups. The goals of this review are to (1) develop a general classification of coating and scarification SETs, (2) facilitate the decision-making process to adopt suitable SETs for arid lands environments, and (3) highlight the benefits of coating and scarification SETs in overcoming biotic and abiotic challenges in ecological restoring degraded dryland. For rehabilitating degraded lands and restoring drylands, it is recommended to 1) optimize SETs that have been used effectively for a long time, particularly those associated with seed physiological enhancement and seed microenvironment, 2) integrate coating and scarification to overcome different biotic and abiotic constraints, and 3) apply SET(s) to a mixture of seeds from various species and sizes. However, more research should be conducted on developing SETs for large-scale use to provide the required seed tonnages for dryland restoration.

Biochar Coating Is a Sustainable and Economical Approach to Promote Seed Coating Technology, Seed Germination, Plant Performance, and Soil Health

Seed germination and stand establishment are the first steps of crop growth and development. However, low seed vigor, improper seedbed preparation, unfavorable climate, and the occurrence of pests and diseases reduces the germination rate and seedling quality, resulting in insufficient crop populations and undesirable plant growth. Seed coating is an effective method that is being developed and applied in modern agriculture. It has many functions, such as improving seed vigor, promoting seedling growth, and reducing the occurrence of pests and diseases. Yet, during seed coating procedures, several factors, such as difficulty in biodegradation of coating materials and hindrance in the application of chemical ingredients to seeds, force us to explore reliable and efficient coating formulations. Biochar, as a novel material, may be expected to enhance seed germination and seedling establishment, simultaneously ensuring agricultural sustainability, environment, and food safety. Recently, biochar-based seed coating has gained much interest due to biochar possessing high porosity and water holding capacity, as well as wealthy nutrients, and has been proven to be a beneficial agent in seed coating formulations. This review presents an extensive overview on the history, methods, and coating agents of seed coating. Additionally, biochar, as a promising seed coating agent, is also synthesized on its physico-chemical properties. Combining seed coating with biochar, we discussed in detail the agricultural applications of biochar-based seed coating, such as the promotion of seed germination and stand establishment, the improvement of plant growth and nutrition, suitable carriers for microbial inoculants, and increase in herbicide selectivity. Therefore, this paper could be a good source of information on the current advance and future perspectives of biochar-based seed coating for modern agriculture.

Why are some plant species missing from restorations? A diagnostic tool for temperate grassland ecosystems

The U.N. Decade on Ecosystem Restoration aims to accelerate actions to prevent, halt, and reverse the degradation of ecosystems, and re-establish ecosystem functioning and species diversity. The practice of ecological restoration has made great progress in recent decades, as has recognition of the importance of species diversity to maintaining the long-term stability and functioning of restored ecosystems. Restorations may also focus on specific species to fulfill needed functions, such as supporting dependent wildlife or mitigating extinction risk. Yet even in the most carefully planned and managed restoration, target species may fail to germinate, establish, or persist. To support the successful reintroduction of ecologically and culturally important plant species with an emphasis on temperate grasslands, we developed a tool to diagnose common causes of missing species, focusing on four major categories of filters, or factors: genetic, biotic, abiotic, and planning & land management. Through a review of the scientific literature, we propose a series of diagnostic tests to identify potential causes of failure to restore target species, and treatments that could improve future outcomes. This practical diagnostic tool is meant to strengthen collaboration between restoration practitioners and researchers on diagnosing and treating causes of missing species in order to effectively restore them.

A global review of seed enhancement technology use to inform improved applications in restoration

Seed-based restoration often experiences poor success due to a range of edaphic and biotic issues. Seed enhancement technologies (SETs) are a novel approach that can alleviate these pressures and improve restoration success. Broadly, SETs have been reviewed for agricultural and horticultural purposes, for specific types of SETs such as coating or priming, or for focal ecosystems. However, information is lacking for SETs within a restoration focused context, and how they are being used to alleviate certain barriers. This review aimed to synthesise the current literature on SETs to understand what SETs are being tested, in which sectors and locations they are being tested, what issues are faced within restoration using SETs, and how SETs are being used to approach these issues. Priming was highlighted as the main SET investigated. Inoculation, pesticide application and magnetic fields were also commonly tested (SETs we termed 'prospective techniques'). SET research mainly occurred in the agricultural sector. More recently, other sectors, such as restoration and rangeland management, have increased efforts into SET research. The restoration sector has focused on extruded pelleting and coating (with activated carbon), in combination with herbicide application, to overcome invasive species, and coating with certain additives to alleviate edaphic issues. Other sectors outside restoration were largely focused on evaluating priming for overcoming these barriers. The majority of priming research has been completed on crop species and differences between these species and ecosystems must be considered in future restoration efforts that focus on native seed use. Generally, SETs require further refinement, including identifying ideal additives and their optimum concentrations to target certain issues, refining formulations for coating and extruded pelleting and developing flash flaming. A bet-hedging approach using multiple SETs and/or combinations of SETs may be advantageous in overcoming a wide range of barriers in seed-based restoration.

UAV-Supported Forest Regeneration: Current Trends, Challenges and Implications

Replanting trees helps with avoiding desertification, reducing the chances of soil erosion and flooding, minimizing the risks of zoonotic disease outbreaks, and providing ecosystem services and livelihood to the indigenous people, in addition to sequestering carbon dioxide for mitigating climate change. Consequently, it is important to explore new methods and technologies that are aiming to upscale and fast-track afforestation and reforestation (A/R) endeavors, given that many of the current tree planting strategies are not cost effective over large landscapes, and suffer from constraints associated with time, energy, manpower, and nursery-based seedling production. UAV (unmanned aerial vehicle)-supported seed sowing (UAVsSS) can promote rapid A/R in a safe, cost-effective, fast and environmentally friendly manner, if performed correctly, even in otherwise unsafe and/or inaccessible terrains, supplementing the overall manual planting efforts globally. In this study, we reviewed the recent literature on UAVsSS, to analyze the current status of the technology. Primary UAVsSS applications were found to be in areas of post-wildfire reforestation, mangrove restoration, forest restoration after degradation, weed eradication, and desert greening. Nonetheless, low survival rates of the seeds, future forest diversity, weather limitations, financial constraints, and seed-firing accuracy concerns were determined as major challenges to operationalization. Based on our literature survey and qualitative analysis, twelve recommendations—ranging from the need for publishing germination results to linking UAVsSS operations with carbon offset markets—are provided for the advancement of UAVsSS applications.

Tracking pesticide exposure to operating workers for risk assessment in seed coating with tebuconazole and carbofuran

BACKGROUND

Coating seed with pesticides is an effective way to control plant pests, however, factory-based coating processes may carry a potential risk to operational workers of chemical exposure. To study the risk, carbofuran and tebuconazole were used to coat corn seed and their subsequent distribution on the bodies of workers was measured at manufacturers XFS and LS (Shanxi, China). Clothing was collected from workers during operations and analyzed using high-performance liquid chromatography.

RESULTS

At XFS, dermal exposure to carbofuran was 4.83, 3.31 and 1.48 mg kg^-1 , and exposure to tebuconazole was 6.88, 5.16 and 1.72 mg kg^-1 for coating, packing and transport workers, respectively. At LS, dermal exposure to carbofuran was 2.32, 0.46 and 0.55 mg kg^-1 , and exposure to tebuconazole was 1.69, 0.46 and 0.70 mg kg^-1 , for coating, packing and transport workers, respectively. The level of pesticide exposure was significantly higher for seed-coating workers than for packing and transport workers. The main area of exposure was the hands for all workers and the lower limbs for packers; exposure was relatively uniform for pesticide handlers. Occupational risk was assessed based on margin of exposure (MOE). In seed-coating, the MOE was greater than 100 for tebuconazole, indicating no potential risk, but ranged from 0.25 to 2.88 for carbofuran, indicating the risk of a health impact.

CONCLUSION

The level of exposure varied depending on type of operation undertaken and body parts of workers' body, but the risk of a health impact was highly associated with pesticide toxicity. This provides a guideline for workers in pesticide manufacturing to ensure safe operation of the seed-coating process. © 2021 Society of Chemical Industry.