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Lipid nanoparticles (LN) composed of biodegradable lipids and produced by green methods are candidates for the encapsulation of pesticides, potentially contributing to decreasing their release in the environment. From a safety-by-design concept, this work proposes LN for the encapsulation of insecticide active ingredients (AI). However, given the complexity of nanoparticles, ecotoxicological studies are often controversial, and a detailed investigation of their effects on the environment is required. Accordingly, this work aimed to produce and characterize LN containing the insecticide lambda-cyhalothrin (LC) and evaluate their safety to crops (Solanum lycopersicum and Zea mays), soil invertebrates (Folsomia candida and Eisenia fetida), and soil microbial parameters. The average particle size for LN-loaded with LC (LN–LC) was 165.4 ± 2.34 nm, with narrow size distribution and negative charge (−38.7 ± 0.954 mV). LN were able to encapsulate LC with an entrapment efficacy of 98.44 ± 0.04%, maintaining the stability for at least 4 months. The LN–LC showed no risk to the growth of crops and reproduction of the invertebrates. The effect on microbial parameters showed that the activity of certain soil microbial parameters can be inhibited or stimulated by the presence of LN at highest concentrations, probably by changing the pH of soil or by the intrinsic properties of LN.

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Inocula containing photosynthetic microorganisms such as cyanobacteria and microalgae can promote the formation of biocrusts, improving the soil properties and allowing ecosystem recovery. The GreenRehab project aims to develop a low-cost, eco-friendly, and easy-to-implement system to rehabilitate burned soils and protocols to evaluate the success of an ecosystem after-fire recovery. For this purpose, native cyanobacteria and microalgae were isolated from soil/biocrusts and tested, with selected strains being cultivated on a large scale. To evaluate the performance of the proposed rehabilitation system (based on the inoculation of native cyanobacteria and microalgae), we analyzed spectral data scanned from a portable visible/near-infrared spectrometer that indirectly estimates top-soil photosynthetic activity. Several spectral indices based on the normalized difference combination of spectral bands were calculated and compared for their ability to assess photosynthetic activity over time. Results showed that treatments with microalgae and cyanobacteria effectively enhanced photosynthetic activity, with Trichocoleus stimulating soil rehabilitation the most. Moreover, the best performing normalized difference index was the one combining the 660 nm and 860 nm wavelengths. Parallelly, very-high resolution imagery obtained from a UAV equipped with a multispectral camera is currently being tested to assess the performance of different inocula previously selected from microcosm experiments in environmental conditions closer to real ones found in post-fire scenarios. Preliminary results led us to develop an integrated protocol for image acquisition, radiometric calibration and photogrammetric post-processing. This allowed us to characterize baseline conditions in the test area, including geomorphology, vegetation and portray fine-scale patterns in greenness and photosynthetic activity. Overall, spectral measurements and indices from portable spectrometers and UAVs open the possibility of assessing which treatments exploited in the GreenRehab project effectively enhance soil rehabilitation and recovery from frequent fires. Such innovation may translate into other 'real-world' applications in ecology, forestry, and agronomy fields.

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