Page 39 - 《广西植物》2026年第7期
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7 期       熊潇等: 马尾松人工林引入阔叶树种异龄混交改造对土壤生物有效性磷组分的影响                                           1 1 3 5

              Effects of introducing broadleaf tree species for uneven ̄

                      aged mixed transformation on soil bioavailable
                                    phosphorus fractions in Pinus

                                          massoniana plantations



                                   1              1             1               2ꎬ3               1
                     XIONG Xiao ꎬ SU Shiquan ꎬ TONG Hui ꎬ ZHU Xinyu ꎬ LUO Zhouyu ꎬ
                                                      1
                                   4
                                                                       1ꎬ3
                        WANG Yi ꎬ ZHENG Danni ꎬ YOU Yeming ꎬ HUANG Xueman                    1ꎬ3∗
             ( 1. Guangxi Key Laboratory of Forest Ecology and Conservationꎬ Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization
               of Subtropical Forest Plantationꎬ College of Forestryꎬ Guangxi Universityꎬ Nanning 530004ꎬ Chinaꎻ 2. China Experiment Center of Tropical
              Forestryꎬ Chinese Academy of Forestryꎬ Pingxiang 532600ꎬ Guangxiꎬ Chinaꎻ 3. Guangxi Youyiguan Forest Ecosystem Observation and Research
                Stationꎬ Youyiguan Forest Ecosystem Observation and Research Station of Guangxiꎬ Pingxiang 532600ꎬ Guangxiꎬ Chinaꎻ 4. International
                      Bamboo and Rattan Centreꎬ Key Laboratory of Bamboo and Rattan Science and Technologyꎬ Beijing 100102ꎬ China )

                 Abstract: Soil phosphorus (P) is a key factor constraining the productivity of subtropical plantation in China. Howeverꎬ
                 long ̄term monocultural management of Pinus massoniana plantations has led to prominent issues such as soil P cycle
                 imbalance. To explore the dynamic characteristics of soil bioavailable phosphorus ( Bio ̄P) fractions and their main
                 influencing factors after the uneven ̄aged mixed transformation of P. massoniana pure plantations by introducing broadleaf
                 tree speciesꎬ this study took southern subtropical P. massoniana plantations as study objects. Based on the Bio ̄P
                 fractionation methodꎬ this study comparatively analyzed the dynamic characteristics of Bio ̄P fractions ( Enzyme ̄Pꎬ
                 Citrate ̄Pꎬ CaCl  ̄Pꎬ HCl ̄P) in the humus layer and eluviated layer of three forest types: mixed plantation of Pinus
                            2
                 massoniana ̄Castanopsis hystrix ( MP )ꎬ multiple species mixed plantation of Pinus massoniana ̄Castanopsis hystrix/
                 Quercus griffithii/ Erythrophleum fordii/ Michelia hedyosperma ( MMP )ꎬ and untransformed Pinus massoniana pure
                 plantation (PPꎬ used as control). Additionallyꎬ this study combined indicators such as soil physicochemical propertiesꎬ
                 microbial biomassꎬ and enzyme activities to identify the main factors influencing Bio ̄P. The results were as follows: (1)
                 Compared with PPꎬ the Citrate ̄P and HCl ̄P contents in the humus layer of MP were significantly increased by 31.50%
                 and 39.78% (P<0.05)ꎬ respectivelyꎬ while the HCl ̄P content in the humus layer of MMP was significantly increased by
                 59.77% (P<0.05). In the eluviated layerꎬ the Enzyme ̄P contents of MP and MMP were significantly increased by
                 39.00% and 91.13% (P<0.05)ꎬ respectivelyꎬ and the CaCl  ̄P contents of MP and MMP were significantly increased by
                                                             2
                 8.40% and 8.90% (P<0.05)ꎬ respectively. (2) Compared with PPꎬ the contents of organic carbon (OC)ꎬ ammonium
                           +
                 nitrogen (NH  ̄N)ꎬ available phosphorus (AP)ꎬ and microbial biomass phosphorus (MBP) in the humus layer of
                           4
                 MMP were significantly reduced (P<0.05). Howeverꎬ the contents of OCꎬ total nitrogen (TN)ꎬ total phosphorus (TP)ꎬ
                 APꎬ microbial biomass carbon (MBC)ꎬ microbial biomass nitrogen (MBN)ꎬ and MBP in the eluviated layer of MP and
                 MMP were significantly increased (P< 0.05). (3) Campared with PPꎬ the enzyme activities associated with carbon
                 (C)ꎬ nitrogen (N)ꎬ and phosphorus (P) cycling in the humus layer of MMP were significantly reduced by 41.42%ꎬ
                 34.22%ꎬ and 30.23% (P<0.05)ꎬ respectively. In contrastꎬ the aforementioned enzyme activities in the eluviated layer of
                 MP were significantly increased by 61.17%ꎬ 157.98%ꎬ and 31.70% (P<0.05)ꎬ respectivelyꎬ and those in the eluviated
                 layer of MMP were significantly increased by 40.91%ꎬ 238.66%ꎬ and 37.93% (P<0.05)ꎬ respectively. (4) Nitrate
                           -
                 nitrogen (NO  ̄N) and AP were the primary regulatory factors influencing Bio ̄P fractions in the humus layerꎬ whereas
                           3
                 TP and enzyme C ∶ N were the main driving factors affecting Bio ̄P fractions in the eluviated layer. In conclusionꎬ the
                 introduction of broadleaf tree species for uneven ̄aged mixed transformation in Pinus massoniana plantations is beneficial
                 to soil P storage and supply. The results of this study provide an important scientific basis for tree species selection and
                 management strategies aimed at improving soil P availability in southern subtropical plantations.
                 Key words: Pinus massoniana plantationꎬ uneven ̄aged mixed transformationꎬ humus layerꎬ soil enzyme activityꎬ
                 bioavailable phosphorus
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