干旱区长期施肥对土壤活性碳组分及团聚体的影响

Effects of long-term fertilization on soil labile carbon fractions and aggregates in an arid area

研究土壤活性有机碳组分和水稳定性团聚体的变化规律，对于评价长期不同施肥处理对绿洲农田土壤环境和区域碳循环具有重要意义。本文选取绿洲农田，设置长期撂荒（20 a）、无施肥、单施全量化肥和2种有机无机配施处理，测定不同处理土壤活性碳组分和水稳定性团聚体含量分布特征。结果表明，在表层（0~20 cm），开垦有利于颗粒碳、可溶性有机碳、可溶性无机碳和水稳定性大团聚体（〉0.25 mm）的累积；与不施肥相比，有机无机配施更有利于活性碳组分累积和水稳定性大团聚体形成和稳定。在相同处理中，表层颗粒碳和水稳定性大团聚体对整个剖面层次累积起主导作用，而表层可溶性有机碳和无机碳与之相反。活性碳组分与团聚体稳定性呈显著正相关。

This paper studied the variation patterns of soil labile organic carbon fractions and water stable aggregates in oasis cropland under effects of different long term fertilization treatments, which could have significance in evaluating oasis cropland soil quality and regional carbon cycle. The study was conducted on an oasis cropland in Xinjiang of Northwest China, and installed four treatments, i.e., long-term （20 years） abandoned cultivation, no fertilization, chemical fertilization, and chemical plus organic fertilization. Cultivation conduced to the accumulation of particulate organic carbon, dissolved organic carbon, dissolved inorganic carbon, and water stable macro-aggregates （〉0.25 mm） in surface soil （0-20 cm）. As compared with no fertilization, chemical plus organic fertilization more conduced to the accumulation of soil labile carbon fractions and the formation and stability of water stable macro-aggregates. In the same treatments, the particulate organic carbon and water stable macro-aggregates in surface soil played a dominant role to their accumulation throughout the soil profile, while the dissolved organic and inorganic carbon in surface soil had a contrast tendency. There was a significant positive correlation between the soil labile carbon fractions and aggregate stability.