Long-term chemical fertilizer use poses sustainability challenges for achieving optimal crop yields and may even diminish yields and fertilizer use efficiency. Sustainable and environmentally friendly agricultural practices must address these challenges by reducing fertilizer application. Biochar emerges as a promising solution, with significant potential for enhancing soil fertility and crop yields. However, its efficacy in sustaining or increasing crop yields under reduced nitrogen (N) fertilizer application remains unclear. This three-year summer maize field study (2019–2021) aimed to elucidate the impact of biochar application on crop productivity, soil characteristics, and economic benefits under varying N fertilizer regimes. Four biochar application rates (0, 8, 16, and 24 t ha−1) were evaluated alongside three N fertilizer rates: conventional N application (200 kg N ha−1), 20 % reduction in N application (160 kg N ha−1), and 40 % reduction in N application (120 kg N ha−1). Biochar was incorporated once at the start of the experiment, while N fertilizer was applied annually. The comprehensive analysis of the three-year data revealed consistent improvements in maize growth, N uptake, grain yield, and economic returns with biochar, even amidst N fertilizer reductions. While the initial year displayed indistinct biochar effects on maize productivity, its impact was more pronounced in the second year than third year. Path analysis underscored the pivotal role of increased soil organic carbon (SOC), total N content, and cation exchange capacity in enhancing maize yield and its components. Moreover, combinations of 40 % N fertilizer reduction with 16 t ha–1 biochar maintained higher maize yields in 2020 and 2021, suggesting the suitability of biochar rates for sustained efficacy over 2–3 years. On average, maize grain yields increased by 8.5–18.4 % with biochar addition from 2019 to 2021, while economic benefits increased by 15.1–18.4 % in 2020 and 2021. These findings highlight the enduring effects of biochar on crop productivity over at least three years, indicating its potential to consistently enhance maize yield and net income while promoting sustainable agricultural practices.

中文翻译：

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减氮结合生物炭对提高玉米生产力和氮素利用的可持续影响


长期使用化肥对实现最佳作物产量提出了可持续性挑战，甚至可能降低产量和肥料使用效率。可持续和环保的农业实践必须通过减少肥料施用来应对这些挑战。生物炭是一种很有前途的解决方案，在提高土壤肥力和作物产量方面具有巨大潜力。然而，在减少氮 （N） 肥料施用的情况下，它在维持或提高作物产量方面的功效仍不清楚。这项为期三年的夏玉米田间研究（2019-2021 年）旨在阐明在不同氮肥条件下施用生物炭对作物生产力、土壤特性和经济效益的影响。评估了四种生物炭施用量（0、8、16 和 24 t ha-1）以及三种氮肥施用量：常规氮肥施用量（200 kg N ha-1）、氮肥施用量减少 20%（160 kg N ha-1）和氮肥施用量减少 40%（120 kg N ha-1）。生物炭在实验开始时掺入一次，而氮肥每年施用一次。对三年数据的综合分析表明，即使在减少氮肥的情况下，生物炭在玉米生长、氮吸收、粮食产量和经济回报方面也有持续改善。虽然第一年生物炭对玉米生产力的影响不明显，但其影响在第二年比第三年更明显。路径分析强调了土壤有机碳 （SOC）、总氮含量和阳离子交换能力的增加在提高玉米产量及其组成部分方面的关键作用。 此外，减少 40% 氮肥与 16 t ha-1 生物炭的组合在 2020 年和 2021 年保持了较高的玉米产量，这表明生物炭用量适合 2-3 年的持续疗效。平均而言，从 2019 年到 2021 年，添加生物炭后玉米籽粒产量增加了 8.5-18.4%，而 2020 年和 2021 年的经济效益增加了 15.1-18.4%。这些发现强调了生物炭在至少三年内对作物生产力的持久影响，表明它有可能在促进可持续农业实践的同时不断提高玉米产量和净收入。