三峡库区坡地脐橙园保护性措施对土壤团聚体结构及碳、氮、磷含量的影响

EFFECTS OF PROTECTIVE MANAGEMENT OF NAVEL ORANGE ORCHARDS ON SLOPE LAND ON STRUCTURE OF AND CARBON,NITROGEN AND PHOSPHORUS CONTENTS IN SOIL AGGREGATES

依托三峡工程生态与环境秭归实验站的8 a长期试验,对5种保护性管理措施下坡地脐橙园土壤团聚体结构与团聚体碳、氮、磷含量分布特征进行了研究。结果表明,脐橙套种多年生白三叶草(CM)和脐橙园地面农作物秸秆覆盖(SM)处理表层土壤(0～5 cm)大于0.25 mm水稳性团聚体含量、团聚体平均重量直径(MWD)值、大于0.25 mm水稳性团聚体氮含量及SM处理表层土壤大于0.25 mm水稳性团聚体磷含量显著高于其他处理;脐橙套种黄花菜等高植物篱(CH)处理和脐橙园沿等高线埋设防渗膜(MM)处理表层土壤大于0.25 mm水稳性团聚体含量及CH处理的MWD值显著高于常规脐橙栽植(CK)和脐橙套种小麦-花生(PC)处理;与CK处理相比,PC处理大于0.25 mm水稳性团聚体含量、MWD值、团聚体碳含量和表层土壤团聚体氮含量没有显著变化,但5～20 cm土壤团聚体磷含量有升高趋势。团聚体MWD与大于0.25 mm水稳性团聚体和团聚体氮含量有极显著相关关系。

Based on the 8-year long experiment at the Zigui Ecological and Environmental Experiment Station for the Three-Gorge Project,effects of five citrus orchard protective management practices were studied on structure of and nutrient（C,N and P） distributions in soil aggregates in navel orange orchards located on slopeland.It was found that Treatment CM（interplantation of citrus trees with white clover,Trifolium repens Linn.） and Treatment SM（mulching of crop straws） were obviously higher than the other treatments in content of 0.25 mm water stable aggregates（WSA）,aggregate mean weight diameter（MWD） and nitrogen content in 0.25 mm WSA in surface soil（0~5 cm）,and Treatment SM was higher than all the other treatments in phosphate content in 0.25 mm WSA in surface soil（0~5 cm）;Treatment CH（interplantation with day lily,Hemerocallis citrina Baroni,or contour hedgerow） and Treatment MM（counter embedment of impermeable membrane） were significantly higher than CK（conventional management） and Treatment PC（interplantation with Wheat（Triticum aestivum Linn.）-Peanut（Arachis hypogaea）） in 0.25 mm WSA and Treatment CH was also significantly higher than CK and PC treatments in aggregate MWD.Compared with CK,Treatment PC did not have any significant effect on 0.25 mm WSA,MWD,soil carbon in aggregate and soil nitrogen in aggregate in the surface soil（0~5 cm）,but increased soil phosphorus in aggregates in the 5~20 cm soil layer.Aggregate MWD was significantly related to contents of 0.25 mm WSA and nitrogen in aggregates.