添加玄武岩粉增强水稻土固碳能力并提高产量

Basalt powder amendment enhances carbon sequestration of paddy soil and increases rice yield

  • 摘要: 基于增强岩石风化作用原理,土壤中施加玄武岩粉可以固定空气中的CO2;同时,玄武岩粉富含各种矿质元素,对水稻等作物生长有一定的促进作用。利用盆栽实验,按照土体质量的0.5%、1.0%、1.5%向红壤性水稻土(过5 mm筛,pH值在5.1左右)中施加玄武岩粉,探究其对土壤无机碳含量和水稻生长的影响。结果表明:(1)玄武岩粉能够显著提高土壤中的无机碳含量(P<0.05),最大施加量组(B1.5%)增幅20.3%,玄武岩粉的风化比率达到21.3%,相当于每公顷土壤中一季水稻的CO2固定量为4.72 t·hm−2。(2)添加玄武岩粉B1.5%组土壤的pH和电导率(EC)分别显著提高0.47个单位和34.4%,但B0.5%、B1.0%和B1.5%组的土壤交换性酸含量显著降低44.7%,84.5%和92.6%(P<0.05);玄武岩粉用量同pH和EC呈线性正相关关系(R=0.96460.9512),而与交换性酸含量呈线性负相关关系(R=−0.9639)。(3)添加玄武岩粉的B0.5%、B1.0%和B1.5%组土壤中有效硅含量分别显著提高3.19、5.79和7.60倍,且玄武岩粉用量和有效硅含量呈线性正相关关系(R=0.992 6);也能够提高水稻茎叶和谷壳中的Si元素含量,B1.5%组有效分蘖数和单株水稻产量显著提高41.2%和42.1%。将玄武岩粉用于酸性稻田土壤,不仅能够通过增强风化作用实现可观的固碳潜力,还可有效中和土壤酸度(提高pH、降低交换性酸),释放有效硅等养分,促进水稻分蘖与产量提升,展现出改良土壤与提升地力的协同效应。

     

    Abstract: Based on the principle of enhanced rock weathering (ERW), as well as applying basalt powder to agricultural soil can sequester atmospheric CO2 while providing essential mineral elements that promote crop growth. A pot experiment was conducted to investigate the effects of basalt powder application (at rates of 0.5%, 1.0% and 1.5% of soil mass) on soil inorganic carbon (SIC) content and rice growth in an acidic red paddy soil (pH≈5.1). The results indicated that:(1) Basalt powder application significantly increased SIC content (P<0.05). The high-rate group (B1.5%) achieved a 20.3% increase in SIC. The weathering ratio of the basalt powder reached 21.3%, which was equivalent to a theoretical sequestration CO2 fixation amount of 4.72 t·hm−2 per rice season. (2) Basalt powder significantly raised soil pH and electrical conductivity (EC). The B1.5% group increased pH by 0.46 and EC by 34.4%, while soil exchangeable acidity decreased significantly by 92.6%(P<0.05) . Correlation analysis revealed a strong linear positive correlation between application rates and pH/EC (R=0.9646 and 0.9512, respectively), and a strong negative correlation with exchangeable acidity (R=−0.9639). (3) Basalt powder substantially enhanced available silicon content in the soil, with 3.19, 5.79 and 7.60 times more in the B0.5%, B1.0% and B1.5% groups, respectively (R=0.9926). This facilitated silicon accumulation in rice stems, leaves, and husks, which enhanced tillering capacity. Consequently, the B1.5% group showed significant increases in effective tiller number (41.2%) and grain yield per plant (42.1%). This study demonstrates that basalt powder application serves as a multi-functional strategy for acidic paddy soils. It achieves substantial carbon sequestration through enhanced weathering, effectively mitigates soil acidity, and boosts rice productivity via the sustained release of available silicon and other minerals.

     

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