生物炭与土壤调理剂对滨海荒芜重盐碱地先锋作物的影响

Effects of biochar and conditioner on pioneer crops planted in coastal barren severe saline-alkali soil

  • 摘要: 以生物改良、开发利用荒芜重盐碱地为目标, 在华北低平原区滨海荒芜重盐碱区开展了施用生物炭(B)与腐殖酸型土壤调理剂(C)对盐碱地先锋作物棉花和油葵的大田试验。生物炭施用量设2个水平(0 kg∙m−2和1.25 kg∙m−2), 调理剂施用量设3个水平(0 kg∙m−2、0.83 kg∙m−2和1.66 kg∙m−2), 共6个处理。研究结果表明, 生物炭显著抑制油葵早期的植株生长, 对后期生长及籽粒数量和重量无显著影响, 提高了油葵茎、叶和籽壳的N、P含量, 增加了茎、籽壳和籽仁的K含量, 促进叶片K、Ca向籽仁转移; 但施用生物炭抑制油葵吸收Mg, 导致茎秆和葵盘Mg含量显著下降, 对Na的吸收没有显著影响。腐殖酸型土壤调理剂则显著促进油葵茎、叶和葵盘生长, 提高了籽粒产量, 促进P向籽仁转移; 施用1.66 kg∙m−2调理剂处理促进N优先向油葵籽仁转移, 大幅度提升茎、叶和葵盘中的Ca含量, 同时提高茎秆Mg含量; 生物炭与土壤调理剂组合施用可消弱生物炭对油葵生长的抑制作用, 提高油葵对N、P、K、Ca的吸收, 促进N、P、K向籽仁的转移, 降低对Na和Mg的吸收, 增强油葵选择性吸收养分和拒盐能力。本研究还表明, 油葵比棉花更适合作为先锋作物在滨海荒芜重盐碱地种植。研究结果为秸秆等废弃物资源化利用、荒芜重盐碱地开发与生物改良以及耐盐适生先锋作物的选择提供理论依据。

     

    Abstract: Mechanisms that assist in reclaiming the coastal barren severe salt-affected soils in arid and semi-arid regions when treated with soil amendments have not been well characterized. Aiming at biological improvement, development, and utilization of barren severe saline-alkali soils, a field experiment was conducted to apply biochar and soil conditioner for pioneer crops planted in the coastal barren severe saline-alkali area of the North China Low Plain. Six treatments included single or combined application of two-level biochar rates (0 and 1.25 kg∙m2) and three-level soil conditioner rates (0, 0.83, and 1.66 kg∙m2) at the start of the experiment. Biochar significantly inhibited younger plant growth at the early stage of oil sunflower but had no marked impact on grown-up plants during the later stage, and grain quantity and yield. Meanwhile, biochar increased N and P contents in stems, leaves, and shells, the K content in stems, shells, and kernels of oil sunflowers, and promoted the transfer of K and Ca from leaves to kernels. However, biochar impeded Mg uptake and decreased the Mg content of stems and sunflower discs but had no significant effect on Na uptake by oil sunflowers. Soil conditioner significantly increased the growth of stems, leaves, and discs, and improved the grain yield. In addition, it promoted P transfer to the kernel. At an application rate of 1.66 kg∙m2, the soil conditioner promoted the transfer of N to the kernel preferentially and significantly improved the Ca content of stems, leaves, and discs, while increasing the Mg content of stems. Co-application of biochar and soil conditioner weakened the negative impact of biochar on plant growth, increasing uptake of N, P, K, and Ca, and facilitating transferring N, P, and K to the kernel, whereas reducing Na and Mg uptake for oil sunflower. Oil sunflowers, other than cotton, as a pioneer crop, are more suitable for planting in coastal barren, severely saline-alkali areas. The results from this preliminary study show that the co-application of biochar and soil conditioner provides an alternative method of waste recovery, converting straw resources into a value-added product, development, and bio-reclamation for coastal barren severely salt-affected soils, and the option of salt-tolerant pioneer crops that are adaptive to coastal areas.

     

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