Sesquioxides and Their Contribution to Soil Aggregation under Long-term Greenhouse Soil Management

The effect of greenhouse soil management on soil aggregation and sesquioxides cycling should be evaluated to maximize the benefits of solar greenhouses rationally. The aggregation process of long-term greenhouse soil management and the influence of aggregate-associated sesquioxides on this process were investigated. Wet-sieving method was used to determine aggregate size distribution. Sesquioxide forms were also determined. The aggregates stability decreased and a similar trend for the stability of microaggregates was observed. The macroaggregate stability in 5 years of greenhouse age was statistically significantly lower than those in other ages. Compared to free and complex oxides, amorphous oxides had the closest relationships with mineral-associated organic carbon and soil aggregation. These results indicated that amorphous oxides were effective in binding aggregates and contributed significantly to macro- and micro- aggregate stability.