CSIRO Land and Water, Sustainable Agriculture Research Flagship, Waite Campus, PMB 2, Glen Osmond, South Australia 5064, Australia.
Chemosphere. 2011 Sep;84(11):1572-7. doi: 10.1016/j.chemosphere.2011.05.052. Epub 2011 Jun 21.
We evaluated wheat straw biochar produced at 450°C for its ability to influence bioavailability and persistence of two commonly used herbicides (atrazine and trifluralin) with different modes of action (photosynthesis versus root tip mitosis inhibitors) in two contrasting soils. The biochar was added to soils at 0%, 0.5% and 1.0% (w/w) and the herbicides were applied to those soil-biochar mixes at nil, half, full, two times, and four times, the recommended dosage (H(4)). Annual ryegrass (Lolium rigidum) was grown in biochar amended soils for 1 month. Biochar had a positive impact on ryegrass survival rate and above-ground biomass at most of the application rates, and particularly at H(4). Within any given biochar treatment, increasing herbicide application decreased the survival rate and fresh weight of above-ground biomass. Biomass production across the biochar treatment gradient significantly differed (p<0.01) and was more pronounced in the case of atrazine than trifluralin. For example, the dose-response analysis showed that in the presence of 1% biochar in soil, the value of GR(50) (i.e. the dose required to reduce weed biomass by 50%) for atrazine increased by 3.5 times, whereas it increased only by a factor of 1.6 in the case of trifluralin. The combination of the chemical properties and the mode of action governed the extent of biochar-induced reduction in bioavailability of herbicides. The greater biomass of ryegrass in the soil containing the highest biochar (despite having the highest herbicide residues) demonstrates decreased bioavailability of the chemicals caused by the wheat straw biochar. This work clearly demonstrates decreased efficacy of herbicides in biochar amended soils. The role played by herbicide chemistry and mode of action will have major implications in choosing the appropriate application rates for biochar amended soils.
我们评估了在 450°C 下生产的小麦秸秆生物炭，以研究其对两种具有不同作用模式（光合作用与根尖有丝分裂抑制剂）的常用除草剂（莠去津和氟乐灵）的生物有效性和持久性的影响。将生物炭以 0%、0.5%和 1.0%（w/w）的比例添加到土壤中，并将除草剂以零、半、全、两倍和四倍的推荐剂量（H(4)）添加到这些土壤-生物炭混合物中。在生物炭改良的土壤中种植一年生黑麦草（Lolium rigidum）1 个月。在大多数施用量下，生物炭对黑麦草的存活率和地上生物量有积极影响，尤其是在 H(4)时。在任何给定的生物炭处理中，随着除草剂施用量的增加，黑麦草的存活率和地上生物量的鲜重都会降低。生物炭处理梯度上的生物量生产差异显著（p<0.01），莠去津的情况比氟乐灵更为明显。例如，剂量反应分析表明，在土壤中添加 1%的生物炭时，莠去津的 GR(50)（即减少杂草生物量 50%所需的剂量）值增加了 3.5 倍，而在氟乐灵的情况下，该值仅增加了 1.6 倍。化学性质和作用模式的结合决定了生物炭对除草剂生物有效性降低的程度。在含有最高生物炭的土壤中，黑麦草的生物量最大（尽管含有最高的除草剂残留），这表明由于小麦秸秆生物炭的存在，降低了化学物质的生物可利用性。这项工作清楚地表明，在生物炭改良的土壤中，除草剂的效果降低。除草剂化学性质和作用模式的作用将对选择适当的生物炭改良土壤的应用率产生重大影响。
