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Rapeseed meal, a nutritious organic fertilizer (OF), contributes to improving soil environment and crop productivity. However, there are also problems, namely slow fertilizer efficiency and low nutrient utilization during the growing season. This 2‐year field trial was conducted to explore the effect of biochar addition on improving the nutrient availability of OF through a comparative study of various biochar application rates under rice‐rapeseed rotation conditions. The findings revealed that, compared to the individual application of chemical fertilizers (CF), OF alone decreased rice yield (2%/2%) and rapeseed yield (6%/10%) in 2019/2020. Compared with OF, combining biochar (15 t ha−1) with OF (OF + B15) significantly increased rice yield (17%/10%) and rapeseed yield (25%/20%) in the first/second year. Additionally, OF + B15 still increased rice yield (14%/7%) and rapeseed yield (12%/13%) for two consecutive years compared to CF. The co‐application of biochar and OF had positive impacts on soil physicochemical properties and enzymes. Compared to OF, OF + B15 elevated soil organic carbon (SOC) by 57%–81%, soil catalase 19%, invertase 14%–20%, urease 17%–19%, and phosphatase 13%–17% during rice season, and similarly increased SOC by 77%–90%, soil catalase 14%–16%, invertase 14%–20%, urease 18%–24%, and phosphatase 16%–17% in rapeseed season. Biochar addition improved soil conditions and enzymatic activities, and the available nutrient supply of OF. Also, the co‐application of biochar and rapeseed meal surpassed the effect of chemical fertilizer alone on the growth and yield of crops. Therefore, biochar coupling with organic fertilizer is an effective fertilization strategy based on resource recycling, which promotes both crop yield and sustainable agriculture. [ABSTRACT FROM AUTHOR]

Acquiring clear acoustic signals is critical for the analysis of animal vocalizations. Bioacoustics studies commonly face the problem of overlapping signals, which can impede the structural identification of vocal units, but there is currently no satisfactory solution. This study presents a bi‐directional long short‐term memory network to separate overlapping echolocation‐communication calls of 6 different bat species and reconstruct waveforms. The separation quality was evaluated using 7 temporal‐spectrum parameters. All the echolocation pulses and syllables of communication calls in the overlapping signals were separated and parameter comparisons showed no significant difference and negligible deviation between the extracted and original calls. Clustering analysis was conducted with separated echolocation calls from each bat species to provide an example of practical application of the separated and reconstructed calls. The result of clustering analysis showed high corrected rand index (82.79%), suggesting the reconstructed waveforms could be reliably used for species classification. These results demonstrate a convenient and automated approach for separating overlapping calls. The study extends the application of deep neural networks to separate overlapping animal sounds. [ABSTRACT FROM AUTHOR]

The quality and nutritional status of agricultural soils are depleting gradually, and biochar is widely used in soil quality improvement. A sustainable approach of biochar application needs a better understanding of its interaction with nitrogen application and the final effect on crop growth. In our study, the effect of different biochar application levels (0, 15, 30, and 60 tons ha−1) in combination with nitrogen fertilizer levels (0, 150, 300, and 450 kg ha−1) on soil properties, rice growth, and nitrogen use efficiency were investigated. The results showed that sole application of biochar (B60) did not promote the rice growth except the soil organic carbon (SOC), total nitrogen, total phosphorous, and available potassium compared with no biochar addition, while a single application of 450 kg N ha−1 (N450) adversely affected the rice physiological and yield traits by destroying rice leaf ultrastructure and reducing the stomatal length by 13%, stomatal width 3% and density 12%, plant height 5%, dry biomass plant−1 4%, spike weight plant−1 8%, and grain weight plant−1 9% compared to N300 unless it was treated in combination with biochar. Biochar can significantly compensate the toxicity of excessive nitrogen and deficiency of low nitrogen fertilizer on rice growth. Compared to a single application of B0+N450 (450 kg N ha−1), combined application of biochar and nitrogen B30+N450 could elevate rice plant nitrogen content by 13%, plant height 30%, aboveground dry biomass plant−1 136%, spike weight plant−1 34%, and grain weight plant−1 36% while increments in total nitrogen accumulation (TNA 79%%) and nitrogen use efficiency (NUE 35%) were noted in B30+N300 treatment. These results suggest that biochar amendment combined with a proper amount of nitrogen fertilizer is an effective approach to promote soil conditions, manage nitrogen utilization, improve plant growth and increase crop yield on a sustainable basis. [ABSTRACT FROM AUTHOR]