Effects of cultivating different crops on soil aggregate stability and organic carbon content in photovoltaic slopes
To explore the influence of planting different crops on the distribution of soil aggregates and their organic carbon content on sloping land,soil samples were collected from four different patches in the photovoltaic(PV)agricultural slopes project area:corn(YM),soybean(DD),pumpkin(NG),and unplanted(CK).The distribution characteristics of mechanically stable soil aggregates,water-stable aggregates,and the organic carbon content of aggregates with different grain sizes(d＞2 mm,0.25mm≤d≤2 mm,d＜0.25 mm)in different soil patches were determined.The destruction rate of soil aggregates was calculated and the correlation between the distribution ratio of soil aggregates and the organic carbon content was analyzed.The results showed that,compared with CK,planting activities significantly reduced the proportion of mechanically stable and water-stable macroaggregates in the soil and increased their destruction rate(P＜0.05).Among different crops,the soil aggregate destruction rate was lowest for NG and highest for YM(P＜0.05),with YM and DD raising it by 44.2%and 23.1%compared with NG,respectively.The soil organic carbon content and water-stabilized macroaggregate organic carbon were also lower in the planting area than in CK(P＜0.05).Among crops,NG had the highest soil organic carbon content,19.3%and 15.4%higher than YM and DD,respectively,and had higher organic carbon contents in different grain-size aggregates(P＜0.05).Correlation analysis showed that the proportion of water-stable macroaggregates was positively correlated with soil organic carbon content(P＜0.05),and negatively correlated with aggregate destruction rate,whereas the opposite was true for microaggregates(P＜0.05).These results indicate that planting crops in the PV agricultural slopes led to soil aggregate destruction and organic carbon depletion,but the effects varied by crop type.Pumpkin planting causes the least soil disturbance and organic carbon loss,making it the most suitable crop for this PV agricultural slope project area.We also recommend adding soil organic matter and adopting conservation tillage practices to mitigate the negative impacts of planting activities on soil quality.
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