State Key Laboratory of Efficient Utilization of Agricultural Water Resources, Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of China, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
College of Agronomy, Northwest A&F University, Yangling 712100, China.
Sci Total Environ. 2024 Dec 15;956:177379. doi: 10.1016/j.scitotenv.2024.177379. Epub 2024 Nov 9.
Biochar application emerges as a valuable soil management strategy for enhancing crop yield; however, the mechanisms underlying the relationships between soil and plants remain unclear after biochar application. In this study, soil pore characteristics and maize yield were assessed in a five-year biochar-application experiment on the Loess Plateau of China, including four treatments: Control (no biochar), low-dose biochar application (LB, 3 t ha), moderate-dose biochar application (MB, 6 t ha), and high-dose biochar application (HB, 9 t ha). Root growth traits were evaluated by cultivating maize in intact soil cores collected from field conditions using X-ray computed tomography. Our findings indicate that, compared to the Control, the HB treatment enhanced macroporosity (> 0.1 mm in diameter), porosity of 0.1-0.5 mm pores, and saturated water content, while reducing macropore connectivity and penetration resistance. However, biochar application treatments did not alter the water retention characteristics from field capacity to permanent wilting point or the plant-available water content (PAWC). Furthermore, the mean angle of primary and seminal roots as well as the length and surface area of entire roots increased in the HB treatment, showing a positive correlation with the porosity of 0.1-0.5 mm pores. The mean diameter of primary and seminal roots, leaf fresh and dry weights, and maize yield also increased in the HB treatment compared to the Control. Partial least squares path modeling analysis indicated that biochar application rates positively impacted on root growth and plant productivity through an indirect influence of soil pore size distribution, with 0.1-0.5 mm pores being particularly crucial for facilitating deeper root penetration and root elongation. These findings demonstrate that biochar application primarily augmented 0.1-0.5 mm pores, rather than affecting smaller pores capable of retaining plant-available water or larger macropores, enhancing deeper rooting and root elongation, thus improving plant productivity and crop yield.
生物炭的应用作为一种有价值的土壤管理策略，可以提高作物产量；然而，在中国黄土高原进行的为期五年的生物炭应用实验中，应用生物炭后土壤与植物之间关系的机制仍不清楚，该实验包括四个处理：对照（无生物炭）、低剂量生物炭应用（LB，3 吨/公顷）、中剂量生物炭应用（MB，6 吨/公顷）和高剂量生物炭应用（HB，9 吨/公顷）。通过使用 X 射线计算机断层扫描从田间条件下采集的完整土壤芯中种植玉米，评估了根生长特性。我们的研究结果表明，与对照相比，HB 处理增加了大孔（>0.1mm 直径）、0.1-0.5mm 孔径的孔隙率和饱和含水量，同时降低了大孔连通性和穿透阻力。然而，生物炭应用处理并没有改变从田间持水量到永久萎蔫点的水分保持特性或植物可用水含量（PAWC）。此外，HB 处理中主根和次生根的平均角度以及整个根系的长度和表面积增加，与 0.1-0.5mm 孔径的孔隙率呈正相关。HB 处理中主根和次生根的平均直径、叶片鲜重和干重以及玉米产量也比对照有所增加。偏最小二乘路径模型分析表明，生物炭应用率通过间接影响土壤孔径分布对根系生长和植物生产力产生积极影响，其中 0.1-0.5mm 孔径对促进更深的根系穿透和根系伸长尤为重要。这些发现表明，生物炭的应用主要增加了 0.1-0.5mm 孔径，而不是影响能够保留植物可用水的较小孔径或较大的大孔，从而增强更深的根系穿透和根系伸长，从而提高植物生产力和作物产量。
