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.

中文翻译：

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生物炭的应用提高了有机肥的养分供应效率，维持土壤质量，促进作物可持续生产

菜籽粕是一种营养丰富的有机肥料（OF），有助于改善土壤环境和作物生产力。但也存在肥效慢、生长季养分利用率低等问题。这项为期两年的田间试验旨在通过稻油轮作条件下不同生物炭施用量的比较研究，探讨添加生物炭对提高OF养分有效性的影响。研究结果显示，与单独施用化肥（CF）相比，单独施用化肥导致 2019/2020 年水稻产量（2%/2%）和油菜籽产量（6%/10%）下降。与OF相比，生物炭（15 t ha ^-1）与OF（OF + B15）组合显着提高了第一年/第二年的水稻产量（17%/10%）和油菜籽产量（25%/20%）。此外，与CF相比，OF+B15仍连续两年提高水稻产量（14%/7%）和油菜籽产量（12%/13%）。生物炭和 OF 的共同施用对土壤理化性质和酶具有积极影响。与OF相比，OF+B15使稻季土壤有机碳（SOC）提高57%~81%，土壤过氧化氢酶提高19%，蔗糖酶提高14%~20%，脲酶提高17%~19%，磷酸酶提高13%~17% ，同样在油菜季节增加了 SOC 77%–90%、土壤过氧化氢酶 14%–16%、蔗糖酶 14%–20%、脲酶 18%–24% 和磷酸酶 16%–17%。添加生物炭改善了土壤条件和酶活性，以及​​ OF 的可用养分供应。此外，生物炭与菜籽粕配施对作物生长和产量的影响超过了单独施用化肥的效果。因此，生物炭与有机肥耦合是一种基于资源循环利用的有效施肥策略，可促进作物产量和可持续农业。