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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