Effect of organic amendment on soil fertility and plant nutrients in a post-fire Mediterranean ecosystem

International audienceBackgrounds and aims In Mediterranean frequentlyburnt areas, the decrease of soil fertility leads to regressivevegetation dynamics. Organic amendments couldhelp to accelerate post-fire ecosystem resilience, byimproving soil properties and plant nutrition. This studywas conducted to assess the potential of a compostedbiosolid to restore an early post-fire shrubland.Methods About 50Mg.ha−1 of fresh co-composted sewagesludge and green wastes were surface applied7 months after fire on a silty-clayey soil. We monitoredover a 2-year period organic matter and nutrient transfersto soil, nutrient responses of dominant plant species,and ecosystem contamination by potentially toxic traceelements.Results Over the experimental survey, compost rapidlyand durably improved soil P2O5,MgO and K2O content,and temporarily increased N-(NO3− + NO2−) content.Plant nutrition was improved more or less durably dependingspecies. The most positive compost effect wason plant and soil phosphorus content. Plant nutrientstorage was not improved 2 years after amendment,suggesting luxury consumption. No contamination bytrace elements was detected in soil and plant.Conclusions The use of compost after fire could helpfor rapidly restoring soil fertility and improving plantnutrition. The increase of soil nutrient pools afteramendment emphazised the diversity of plant nutritionaltraits. Eutrophication risk could occur from high compostand soil P2O5 content

Immature stages of Spodoptera albula (walker) (Lepidoptera: Noctuidae): developmental parameters and host plants.

This study aimed to detail the temporal and morphological parameters of the immature stages of Spodoptera albula (Walker 1857) under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photophase) and to gather information about their larval host plants. For this purpose, a new rearing method and artificial diet was employed and validated. The viability of the egg, larval, pupal and pre-pupal stages was 94.54, 97.33, 93.84 and 92.34%, respectively. The average duration of the egg, larval, pupal and pre-pupal stages was 4.14, 16.37, 1.69, and 9.34 days, respectively. During the larval stage, 80.85% of females and 93.99% of males passed through six and remaining through seven instars, with significant larval protandry. The larvae that developed through six and seven instars exhibited a mean growth rate of 1.58 and 1.48, respectively. Fifty five host plant species belonging to 29 families are listed. The female pupae were significantly larger, exhibiting protogyny. Both the rearing methods as well as the larval diet proved adequate, providing more detailled observations of the biological cycle, especially the larval stage, and resulting in an overall survival of almost 80%