Biochar has been shown to be potentially beneficial for enhancing yields and soil properties, and diminishing nitrogen (N) losses. However, it remains unclear how biochar regulates soil carbon (C) and N to mitigate N losses induced by straw mixing with N fertilizer in dryland soils. Therefore, we investigated the effects of straw mixing (S₁), S₁ with biochar (SB) and no straw inputs (S₀), and routine urea application rates (N₁) and 70% of routine rates (N_0.7) on yields and N losses, and identify the relationship between N losses and soil C and N compounds. Results showed that N_0.7 and N₁ were suitable for the maize and wheat seasons, respectively, contributing to mitigating N losses without reducing crop yields. Moreover, in the maize season, N_0.7‐SB significantly mitigated the straw‐induced NH₃‐N and N₂O‐N emissions by 106% and 81%, respectively. In the wheat season, N₁‐SB reduced the straw‐induced NH₃‐N and N₂O‐N emissions by 35% and 66%, respectively. In addition, N_0.7‐SB sharply reduced soil inorganic N (SIN) storage in the maize season. Furthermore, the NH₃‐N and N₂O‐N emission rates were negatively correlated with dissolved organic carbon/SIN content (0–20 cm) (DOC/SIN_0‐20). N losses (N₂O‐N and NH₃‐N emissions and SIN storage) were positively correlated with SIN_0‐20, but negatively correlated with soil organic carbon / SIN_0‐20 (SOC/ SIN_0‐20). This study provides further evidence that biochar with an appropriate N application rate decreased SIN_0‐20 and increased DOC/SIN_0‐20, thus reducing SIN storage and the straw‐induced gaseous N emissions without decreasing crop yields.

中文翻译：

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添加生物炭可减轻因秸秆混入和施氮肥引起的氮损失

生物炭已被证明对提高产量和土壤特性以及减少氮素损失具有潜在的好处。然而，目前尚不清楚生物炭如何调节土壤碳（C）和氮，以减轻旱地土壤中秸秆与氮肥混合引起的氮损失。因此，我们研究了秸秆混合（S ₁），S ₁与生物炭（SB）和无秸秆输入（S ₀），常规尿素施用量（N ₁）和常规施用量的70％（N _0.7）的影响。产量和氮损失，并确定氮损失与土壤碳和氮化合物之间的关系。结果表明，N _0.7和N ₁分别适合于玉米和小麦季节，有助于减少氮素的损失而不降低作物的单产。此外，在玉米季节，N _0.7 -SB显着降低了稻草引起的NH ₃ -N和N ₂ O-N排放，分别减少了106％和81％。在小麦季节，N ₁ -SB分别使稻草引起的NH ₃ -N和N ₂ O-N排放减少了35％和66％。此外，N _0.7 -SB大大减少了玉米季节的土壤无机氮（SIN）存储。此外，NH ₃ -N和N ₂ O-N排放速率与溶解的有机碳/ SIN含量（0-20 cm）呈负相关（DOC / SIN_0-20）。N损失（N ₂ O‐N和NH ₃ ‐N排放以及SIN储存）与SIN _0-20正相关，而与土壤有机碳/ SIN _0-20（SOC / SIN _0-20）负相关。这项研究提供了进一步的证据，表明适当施氮量的生物炭降低了SIN _0-20并增加了DOC / SIN _0-20，从而减少了SIN的储存和稻草诱导的气态N排放，而没有降低作物的单产。