• ISSN 1008-505X
  • CN 11-3996/S

不同生物炭用量下锌肥提高冬小麦锌吸收及土壤供锌能力的效应

Effects of biochar application rates on zinc fertilizer efficacy: enhancing zinc uptake IN winter wheat and soil zinc supply capacity

  • 摘要:
    目的 探究长期施用生物炭条件下,锌肥及其与有机肥配施对旱作麦田土壤锌含量及小麦锌累积量的影响。
    方法 生物炭的长期田间定位试验始于2012年,包括了4个生物炭添加量处理:0 t/hm2 (C0)、10 t/hm2 (C10)、30 t/hm2 (C30)、50 t/hm2 (C50)。2020年在该定位试验的每个小区中设置不施锌(CK)、施锌(Zn)、锌肥配施有机肥(Zn+M)三个微区。2021年冬小麦收获后,测定了冬小麦地上部各部位生物量和锌含量,并采集土壤样品分析了全锌、有效锌和锌组分含量。
    结果 施用生物炭9年后,对土壤全锌(Tol-Zn)和有效锌(DTPA-Zn)无显著影响。施锌显著提高了土壤Tol-Zn和DTPA-Zn含量,Zn和Zn+M处理土壤Tol-Zn较CK显著提高7.5%和12.5%,DTPA-Zn提高了210.2%和249.7%。此外,Zn+M处理土壤Tol-Zn、DTPA-Zn相比于Zn处理提高了4.7%、12.7% (P<0.05)。不施锌CK下,施用生物炭降低了土壤交换态锌(Ex-Zn)含量但提高了松结有机态(Lom-Zn)和氧化锰结合态锌(Mon-Zn)含量;在Zn处理下,生物炭施用提高了Lom-Zn、紧结有机态锌(Sbo-Zn)和碳酸盐结合态锌(Carb-Zn)含量,降低了Mon-Zn含量;Zn+M处理下,C50、C30的Lom-Zn含量显著高于C10和C0 (P<0.05),其他形态锌各处理间无显著差异。相较于CK,Zn和Zn+M处理提高了土壤Lom-Zn、Carb-Zn、Sbo-Zn和Res-Zn含量,且Zn+M的提升效果更高。施用生物炭和锌肥显著提高了冬小麦籽粒干物质量,冬小麦各部位平均干物质量和锌含量大体表现为Zn+M>Zn>CK (P<0.05)。不施锌肥CK下,C30和C50处理提高了冬小麦茎锌含量,C50提高了叶锌含量,但两个处理降低了籽粒锌含量。与CK相比,Zn和Zn+M处理显著提高了籽粒锌平均含量,增幅分别为13.7%和28.3%,且Zn+M的增幅显著高于Zn处理。相较于CK处理,Zn和Zn+M显著提高冬小麦茎+叶锌累积量203.0%和257.2%,籽粒+壳锌累积量40.0%和64.8%,地上部总锌累积量60.6%和89.1%,同样,Zn+M处理的提升效果大于Zn处理。相关性分析表明,小麦锌累积量与土壤所有形态的锌含量呈正相关(P<0.01),尤其与DTPA-Zn和Lom-Zn含量的相关性最强。随机森林分析表明,Sbo-Zn、Lom-Zn和DTPA-Zn对冬小麦锌累积量的贡献最大。
    结论 长期施用生物炭没有增加旱作麦田土壤的全锌和有效锌含量,但增加了有效性较高的Lom-Zn含量。锌肥或锌肥有机肥配施可显著提高土壤全锌和有效锌含量,特别是增加松结有机态锌、紧结合有机态锌含量,提升了锌的潜在供应能力。不施用锌肥,高量生物炭可以促进冬小麦籽粒的生物量,但降低其锌含量;施用锌肥条件下,生物炭可进一步提高冬小麦产量,且在施用10~30 t/hm2范围内不影响小麦籽粒的锌含量。锌肥与有机肥配合施用提高土壤锌有效性、小麦籽粒锌含量的效果显著好于锌肥单施。

     

    Abstract:
    Objectives To investigate the effects of zinc fertilizer and its combination with organic fertilizer on soil zinc content and wheat zinc accumulation in dry-crop wheat fields under different biochar application rates in the long term.
    Methods A long-term field experiment investigating biochar application was established in 2012 with four treatment levels: 0 t/hm2 (C0), 10 t/hm2 (C10), 30 t/hm2 (C30), and 50 t/hm2 (C50). In 2020, three subplot treatments were implemented within each main plot: no zinc application (CK), zinc fertilizer alone (Zn), and zinc fertilizer combined with organic manure (Zn+M). Following the 2021 winter wheat harvest, we measured aboveground biomass and zinc concentrations in plant tissues. Soil samples were collected to analyze total zinc content, bioavailable zinc, and zinc fraction distribution.
    Results After nine years of biochar application, no significant effects were observed on total zinc (Tol-Zn) or available zinc (DTPA-Zn) in the soil. Zinc application significantly increased soil Tol-Zn and DTPA-Zn levels. Compared to the control (CK), Zn and Zn+M treatments elevated Tol-Zn by 7.5% and 12.5%, respectively, and DTPA-Zn by 210.2% and 249.7%. Furthermore, Zn+M enhanced Tol-Zn and DTPA-Zn by 4.7% and 12.7% compare to Zn alone (P<0.05). Under CK (no zinc), biochar reduced exchangeable zinc (Ex-Zn) but increased loosely organic-bound (Lom-Zn) and manganese oxide-bound zinc (Mon-Zn). In Zn-treated soils, biochar raised Lom-Zn, tightly organic-bound zinc (Sbo-Zn), and carbonate-bound zinc (Carb-Zn), while reducing Mon-Zn. With Zn+M, Lom-Zn levels under C50 and C30 biochar treatments were significantly higher than C10 and C0 (P<0.05), though no differences were observed for other zinc fractions. Compared to CK, both Zn and Zn+M enhanced Lom-Zn, Carb-Zn, Sbo-Zn, and residual zinc (Res-Zn), with Zn+M demonstrating greater efficacy. The combined application of biochar and zinc significantly increased winter wheat grain biomass. Across plant tissues, biomass and zinc content followed the order: Zn+M > Zn > CK (P<0.05). Under no zinc application (CK), C30 and C50 treatments increased zinc content in wheat stems, with C50 also enhancing leaf zinc content. However, both treatments reduced zinc levels in grains. Compared to CK, Zn and Zn+M treatments increased average grain zinc content by 13.7% and 28.3%, respectively, with Zn+M demonstrating significantly greater enhancement than Zn alone. Compare to CK, stem+leaf accumulation rose by 203.0% and 257.2%, grain+shell by 40.0% and 64.8%, and total aboveground accumulation by 60.6% and 89.1%. Zn+M again outperformed Zn in enhancement effects. Correlation analysis revealed significant positive associations (P<0.01) between wheat zinc accumulation and all measured soil zinc fractions, with the strongest relationships observed for DTPA-Zn and Lom-Zn. Random forest analysis identified Sbo-Zn, Lom-Zn, and DTPA-Zn as the primary contributors to zinc accumulation in winter wheat.
    Conclusion Long-term biochar application did not increase total or available zinc in rainfed wheat field soils but elevated more bioavailable Lom-Zn fractions. Zinc fertilizer application, particularly when combined with organic manure, significantly enhanced total zinc, available zinc, and organic-bound zinc fractions (loosely- and tightly-bound), thereby enhancing its potential availability. Without zinc fertilization, high biochar rates increased winter wheat grain biomass but reduced grain zinc content. When zinc fertilizer was applied, biochar further boosted grain yield without compromising zinc content at application rates of 10-30 t/hm2. The combined use of zinc fertilizer and organic manure proved significantly more effective than zinc fertilizer alone in improving soil zinc availability and grain zinc enrichment.

     

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