Page 58 - 《广西植物》2024年第7期
P. 58

1 2 5 8                                广  西  植  物                                         44 卷
             ( 1. Guangxi Key Laboratory of Forest Ecology and Conservationꎬ College of Forestryꎬ Guangxi Universityꎬ Nanning 530004ꎬ Chinaꎻ 2. Guangxi
                      Youyiguan Forest Ecosystem National Observation and Research Stationꎬ Youyiguan Forest Ecosystem Observation and
                                      Research Station of Guangxiꎬ Pingxiang 532600ꎬ Guangxiꎬ China )


                 Abstract: In order to improve the phosphorus (P) deficiency in the soil of Eucalyptus plantations in subtropical Chinaꎬ
                 we used biochar (BC) as a soil amendment to investigate the soil of Eucalyptus plantations (15 years old). Meanwhileꎬ
                 we added the different amounts [0 (CK)ꎬ 2%ꎬ 5%ꎬ 10% and 20%] of BC through the laboratory culture experiment to
                 evaluate the effects of different amounts of BC on P components and transformation in soil and its relationship with soil
                                                                                                -
                 physicochemical properties. The results were as follows: (1) Compared to CKꎬ the nitrate nitrogen (NO  ̄N)ꎬ total
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                 phosphorus ( TP)ꎬ microbial biomass phosphorus ( MBP) and pH values were significantly increased at 20% BC
                 additionꎬ respectively (P< 0.05)ꎬ the MBP and pH values were significantly increased at 2%ꎬ 5%ꎬ and 10% BC
                 additionꎬ respectively (P<0.05)ꎬ while no marked difference was found in other soil physicochemical properties. (2)
                 Compared to CKꎬ the labile P (LP) was significantly increased at 2% of BC addition (P<0.05)ꎬ the available P (AP)
                 and LP were significantly increased at 5% and 10% of BC additionsꎬ respectively (P<0.05). Moreoverꎬ the APꎬ LP and
                 occluded P (OP) were significantly increased at 20% BC addition (P<0.05)ꎬ whereas the moderately available P
                 (MP) had no significant change under the four BC additions. (3) The total activities of β ̄glucosidase (BG)ꎬ β ̄N ̄
                 acetylglucosaminidase (NAG)ꎬ L ̄leucine aminopeptidase (LAP)ꎬ and acid phosphatase (ACP) involved in Cꎬ N and
                 P transformations increased significantly at 10% and 20% BC additions than those in CK (P<0.05). (4) Correlation
                 analysis showed that ln(BG) and ln(NAG+LAP) were positively correlated with ln(ACP)ꎬ respectively (P<0.05). In
                 additionꎬ redundancy analysis (RDA) indicated that pHꎬ TN and TP appeared to be the primary drivers of variations in
                 soil P components of Eucalyptus plantations. Furthermoreꎬ structural equation model (SEM) revealed that the pHꎬ C ∶ P
                 and N ∶ P of soil were the most critical factors driving P transformation. In conclusionꎬ our findings suggest that different
                 amounts of BC improve the enzyme activities related to Cꎬ N cyclings by affecting soil physicochemical properties and
                 improving the P supply potential of soil in Eucalyptus plantations. Notablyꎬ 20% BC addition had the optimum
                 effect. This study provides critical theoretical guidance for gaining knowledge on soil nutrient management in Eucalyptus
                 plantations and facilitating the sustainable development of forests in subtropical China.
                 Key words: biocharꎬ Eucalyptus plantationꎬ soil phosphorus componentꎬ soil enzyme activityꎬ subtropics



                磷( phosphorusꎬP) 是植物生活史中必不可少                   现象并随着下渗水大量流失ꎬ导致土壤 P 供应不
            的矿质营养元素之一(曹娟等ꎬ2014)ꎬ参与植物体                          足(Zhang et al.ꎬ 2021)ꎮ 因此ꎬ长期以来 P 被认为
            内糖、蛋白质和叶绿素等物质的合成ꎬ还以多种方                             是限制该区域人工林生态系统生产力及可持续经
            式参与植物从个体发生到自然死亡所经历的全部                              营的最关键因子之一(Crous et al.ꎬ 2015)ꎬ深入研
            生理生化过程ꎬ而土壤中的 P 是植物获取 P 的来                          究亚热带人工林土壤 P 组分变化趋势和转化机制
            源ꎬ其形态结构直接影响土壤 P 的生物有效性( 李                          有助于提高土壤 P 的有效性ꎬ并有益于维持生态
            新乐等ꎬ2015)ꎮ P 在土壤中的形态分为无 机 磷                        系统的生产力和生态过程的可持续发展ꎮ

            ( inorganic phosphorusꎬ Pi ) 和 有 机 磷 ( organic         生物质炭( biocharꎬBC) 是生物质在无氧或缺
            phosphorusꎬPo) 两种 ( 高 艺 伦 等ꎬ2022)ꎮ Pi 多 以          氧条件下热解转化的产物( 刘亦陶等ꎬ2019)ꎮ 研
            正磷酸盐的形态存在ꎬ在我国以侵蚀性红壤酸性                              究表明ꎬBC 作为一种新材料ꎬ在人为输入土壤生
            土为主的南方地区ꎬ其大多与 Fe、Al 结合形成难以                         态系统后ꎬ可以有效改良土壤和提升地力( 郜礼阳
            被植物吸收的磷酸盐ꎮ Po 在全球范围的土壤 P 库                         等ꎬ2021)ꎻBC 的多孔性有利于土壤孔隙度的增加
            中储量丰富ꎬ占总 P 的 15% ~ 80%ꎬ但却需经过生                      和土壤容重的降低(赵泽州等ꎬ2021)ꎬ其巨大的比
            物矿化转变为溶解磷酸盐才能被植物吸收利用                               表面积可释放大量电荷ꎬ有效吸附 N、P 等元素ꎬ促
            (Achat et al.ꎬ 2009)ꎮ 由于亚热带地区具有多雨                  进土壤养分的固持( 武玉等ꎬ2014)ꎻBC 即使在施
            的气候条件ꎬ会使土壤中的有效性 P 出现“ 淋溶”                          用量较低的情况下ꎬ仍具有较强的维持土壤生产
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