Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-08-25 Cooperative journals: 《广西植物》
Abstract： In order to improve the Phosphorus (P) deficiency in the soil of Eucalyptus plantations in subtropical China. We used biochar (BC) as a soil amendment, investigating the soil of Eucalyptus plantations (15 years old). Meanwhile, we added the different proportions 0(CK), 2%, 5%, 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 CK, the nitrate nitrogen (NO3--N), total phosphorus (TP), microbial biomass phosphorus (MBP) and pH values were significantly increased at 20% BC addition, respectively (P<0.05), the MBP and pH values were significantly increased at 2%, 5%, and 10% BC addition, respectively (P<0.05), while no marked difference was found in other soil physicochemical properties. (2) compared to CK, the labile P (LP) was significantly increased at 2% of BC addition (P<0.05), the available P (AP) and LP were significantly increased at 5% and 10% of BC addition, respectively (P<0.05). Moreover, the AP, LP and oclude P (OP) were significantly increased at 20% BC addition (P<0.05), whereas the moderately available P (MP) had no significant change under the four BC supplemental levels. (3) The total activity of hydrolytic enzymes involved in C metabolism (β-glucosidase, BG), N metabolism ( β -N-acetylglucosaminidase, NAG and L-leucine aminopeptidase, LAP), and P metabolism (acid phosphatase, ACP) increased significantly at 10% and 20% of BC addition than those in CK (P<0.05). (4) Correlation analysis showed that ln (BG) and ln (NAG+LAP) were positively correlated with ln (ACP), respectively (P<0.05). In addition, redundancy analysis (RDA) indicated that pH, TN and TP appeared to be the primary drivers of variations in soil P components of Eucalyptus plantations. Furthermore, structural equation model (SEM) revealed that the pH, C:P and N:P of soil were the most critical factors driving P transformation. In conclusion, our findings suggest that different amounts of BC improve the enzyme activities related to C, N cyclings by affecting soil physicochemical properties and improving the P supply potential of soil in Eucalyptus plantations. Notably, 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.
Subjects: Biology >> Botany submitted time 2018-03-27 Cooperative journals: 《广西植物》
Abstract：林下植被是生态系统的重要组成成分，在维持森林垂直结构中发挥着不可或缺的作用。为了研究不同更新方式下桉树人工林林下植物功能群的变化规律及其主要影响因素，综合运用野外调查和室内分析的方法，评估桉树人工林林下植物功能群的组成、分布及更新方式和相关环境因子之间的关系。研究结果表明：林分更新5年后，除了非禾本科杂草功能群外，其他林下植物功能群的物种丰富度均呈现不同程度的增加，但与对照组（砍伐迹地）相比，其差异程度均不显著（P> 0.05）；与对照组相比，藤本和蕨类功能群的相对多度也出现增加趋势，但禾本科草本功能群显著减少（P< 0.05）；木本、藤本和蕨类功能群的相对盖度也呈现增加趋势，但禾本科草本功能群与对照组相比显著减少（P< 0.05）；主成分分析（PCA）发现萌芽更新或植苗更新林的林下植物功能群组成和分布与对照组相比均发生了显著的变异，但不同更新方式（萌芽和植苗）下其林下植物功能群组成和分布差异不明显；通过冗余分析（RDA）确定了冠层透光系数、土壤孔隙度、坡向和土壤氮磷比是影响该林地林下植物功能群的主要因子，它们的叠加效应能解释大于75%的林下植物功能群的变异，最终模型通过排序得到冠层透光系数是影响该林地林下植物功能群的最主要因子。短期的研究发现萌芽和植苗这两种不同的更新方式对桉树林下植物功能群的影响有限，这可能与这两种更新方式形成的林冠结构和土壤理化性质差异性较小有关。
Subjects: Biology >> Botany >> Applied botany submitted time 2024-03-26 Cooperative journals: 《广西植物》
Abstract： Phosphorus (P) is one of the essential elements for plant growth and is a key factor in maintaining the productivity of subtropical forest ecosystems. Chinese fir (Cunninghamia lanceolata) is mainly distributed in subtropical areas of China, and its soil acidification and phosphorus utilization efficiency are low. It is of great significance to study the effect of Chinese fir plantation transformation on soil P for the stability of ecosystem and sustainable forest management. In this study, the rhizosphere soil and non-rhizosphere soil were collected from the replanted Chinese fir plantation, Castanopsis hystrix plantation, Mytilaria laosensis plantation and the mixed plantation of Castanopsis hystrix and Mytilaria laosensis on the cutting-blank of Chinese fir plantation in South Asia, and the effects of soil P component and transformation on the transformation of Chinese fir plantation into broadleaved forest were studied. The results showed that: (1) The content of microbial biomass phosphorus and the activity of acid phosphatase in rhizosphere and non-rhizosphere soil of the modified Castanopsis hystrix plantation, Mytilaria laosensis plantation and the mixed plantation of Castanopsis hystrix and Mytilaria laosensis were significantly higher than those of Chinese fir plantation. Soil total phosphorus of Castanopsis hystrix plantation and the mixed plantation of C. hystrix and Mytilaria laosensis was more easily converted to quick available phosphorus than those of Chinese fir plantation and Mytilaria laosensis plantation. (2) The contents of calcium chloride extraction phosphorus in rhizosphere and non-rhizosphere soil of Castanopsis hystrix plantation and the mixed plantation of Castanopsis hystrix and Mytilaria laosensis were significantly higher than those of Chinese fir plantation and M. laosensis plantation, and the contents of enzyme extraction phosphorus, hydrochloric acid extraction phosphorus and citric acid extraction phosphorus in rhizosphere and non-rhizosphere soil of Mytilaria laosensis plantation and Castanopsis hystrix/Mytilaria laosensis mixed plantation were significantly higher than those of Chinese fir plantation and Castanopsis hystrix plantation. (3) RDA results showed that soil water content and microbial biomass carbon were the key factors regulating P components in rhizosphere and non-rhizosphere soils, respectively. In summary, the transformation of Chinese fir plantation into broadleaved forest is conducive to the storage and supply of forest soil P, and this study provides an important scientific basis for tree species selection and management strategies to improve soil P availability in south subtropical plantations.
Subjects: Biology >> Botany >> Applied botany submitted time 2024-01-03 Cooperative journals: 《广西植物》
QIN Huiting
YAN Jinliu
HUANG Haimei
LI Jiajun
XIANG Mingzhu
LI Changhang
HUANG Xueman
ZHAO Lijun
YOU Yeming
Abstract： Organic phosphorus (Po) is an important part of soil phosphorus reservoir. In order to investigate the effects of the soil Po fraction distribution properties in Pinus massoniana plantations after close to nature silviculture, we investigated the pure P. massoniana plantations (PP) and P. massoniana broad leaved mixed plantations (CP) after close to nature silviculture in southern subtropical China. After collecting 0~10 cm soil sample, it was screened into >2 mm, 0.25~2 mm and <0.25 mm particle size fractions using the dry sieving method. We measured the Po fraction, microbial biomass phosphorus (MBP) and acid phosphatase (ACP) activity in the bulk soil and aggregates to understand the distribution of the Po fraction and its drivers. The results were as follows: (1) Soil Po fractions changed in CP compared to PP, with highly recalcitrant organophosphorus (HRO P) and moderately labile organophosphorus (MLO P) markedly greater in the bulk soil and soil aggregates than in PP (P 0.05), while labile organophosphorus (LO P) and moderately recalcitrant organophosphorus (MRO P) were not significantly different in CP and PP. In addition, there was no consistent pattern of change in the Po fractions in the bulk soil and soil aggregates between PP and CP. (2) The size of the proportion of each form of Po in PP was HRO P>MRO P>MLO P>LO P, while CP was HRO P>MLO P>MRO P>LO P. (3) The MBP and ACP activity in CP was markedly greater than that of PP in the bulk soil and the soil aggregates, and there was a tendency for the ACP activity to increase with the decrease in the size of the aggregates. (4) Redundancy analysis revealed that soil available phosphorus (AP), mean weight diameter (MWD), MBP and total nitrogen (TN) were the main drivers of the soil Po fraction. In conclusion, the close to natural forest management model is beneficial to the accumulation and transformation of soil phosphorus in P. massoniana plantation. This study provides a theoretical basis for the improvement of soil quality and productivity in P. massoniana plantations.
Subjects: Biology >> Botany >> Applied botany submitted time 2020-08-03 Cooperative journals: 《广西植物》
Abstract：该研究以二代巨尾桉/降香黄檀混交林（MP）作为研究对象，并以邻接的二代巨尾桉纯林（PP）作为对照（CK），采用磷脂脂肪酸（PLFAs）和土壤酶活性分别表征土壤微生物群落结构和功能，重点探究南亚热带 PP 引入降香黄檀混交种植对土壤微生物群落结构和功能的影响。结果表明：与 PP 相比，（1）MP 的土壤有机碳（SOC）、总氮（TN）、铵态氮（NH4+-N）、硝态氮（NO3--N）和 pH 值分别显著或极显著增加了 61.92%（P<0.05）、60.12%（P<0.05）、72.87%（P<0.01）、488.49%（P<0.01）和 15.97%（P<0.05）；（2）MP 的真菌/细菌（F/B）显著降低，但总微生物生物量、革兰氏阴性菌/阳性菌（G-/G+）并无显著变化；（3）MP 的土壤微生物群落组成发生了显著变化，而 pH 值、NH4+-N 和 C/Nlitter是驱动其微生物群落组成发生变异的最显著性因子；（4）MP 的β-葡萄糖苷酶（BG）和 N-乙酰-葡萄糖苷酶（NAG）活性显著提高，而过氧化物酶（PER）活性显著降低，酚氧化酶（PO）和酸性磷酸酶（ACP）活性没有显著变化。该研究说明在连续短周期经营的桉树林中套种固氮树种降香黄檀，将可能是提高桉树林土壤质量的一种有效的经营管理措施。
Subjects: Biology >> Botany submitted time 2022-12-29 Cooperative journals: 《广西植物》
ZHANG We
LI Jiajun
XIANG Mingzhu
HUANG Haimei
LI Changhang
YAN Jinliu
GAO Guannv
SU Xiaoyan
YOU Yeming
HUANG Xueman
Abstract：
Soil aggregates are the basic unit of soil structure. The stability of soil aggregates is an important indicator for evaluating soil structure and soil fertility. In order to reveal the response mechanism of particle size distribution and stability of soil aggregates after the mixture of Eucalyptus urophylla and Acacia mangium (nitrogen-fixing tree species).We measured the distribution and stability of aggregates indicators such as mean weight diameter (MWD), geometric mean diameter (GMD), mass fractal dimension (Dm), water stable aggregates (WSA), percentage of aggregates destruction (PAD) and aggregates stability index (ASI) in the 0~10 cm and10~20 cm soil layers by the dry sieving method and the wet sieving method, and a pure plantation of E. urophylla (PP) and a mixed plantation containing E. urophylla and A. mangium (nitrogen-fixing tree species) (MP) were selected as the research objects. The results were as follows: (1) Compared with PP, the soil physicochemical properties of MP were improved in varying degrees, especially soil pH, organic carbon (SOC) and total nitrogen (TN). (2) The particle size distribution of soil aggregates in MP was better than that of PP, and the differences mainly lied in the particle sizes of >2 mm and <0.25 mm, but both were dominated by large aggregates (>0.25 mm). Compared with PP, the mechanical stability of aggregates in MP only increased significantly at 0~10 cm soil layer, but the water stability of aggregates in MP increased significantly at 0~10 cm and 10~20 cm soil layer. The mechanical stability and water stability of soil aggregates tended to decrease with the deepening of soil layer. (3) Mantel analysis showed that the stability of aggregates was significantly correlated with pH, SOC, TN, TP, BD and SP, and the stability of aggregates had the strongest correlation with TN. RDA analysis indicated that TN was the most critical factor driving the variation of stability aggregates. Our findings suggest that nitrogen-fixing tree species A. mangium can significantly improve proportion of macroaggregates (>0.25 mm) and the stability of soil aggregates in Eucalyptus plantations. This study can provide a theoretical guidance for soil and water conservation, soil nutrient management and sustainable management of Eucalyptus plantations in the South Asian tropics.
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