不同灌溉方法对保护地土壤有机质及氮素影响的研究

分层采集连续7年分别用渗灌、滴灌和沟灌灌溉的保护地0～80cm土层土壤样品,测定有机质、全氮及无机态氮和有机态氮含量,研究灌溉方法对土壤氮素形态及其数量剖面分布的影响。结果表明,三种灌溉处理0～80cm剖面土壤有机质含量变化范围为8.47～36.48 g kg-1,渗灌与滴灌有机质剖面分布相似,二者与沟灌差异较大;沟灌除30～40cm层次有机质含量低于渗灌和滴灌外,其它层次有机质含量均高于渗灌和滴灌处理。土壤全氮含量变化范围为0.72～3.97 g kg-1,在0～20cm土层不同灌溉方法之间差异显著,渗灌最大,沟灌次之,滴灌最小。无机硝态氮、铵态氮含量的变化范围分别为19.16～1442.06 mg kg-1和0～15.28 mg kg-1,在0～20cm土层各处理之间差异较为明显,以渗灌最大,沟灌次之,滴灌最小。有机态氮含量的变化范围为683.79～2512.87 mg kg-1,各处理之间的差异主要表现在0～30cm土层,其中0～10cm土层以渗灌处理有机态氮含量最高、沟灌次之,滴灌最低,10～30cm沟灌处理有机态氮含量却高于渗灌和滴灌处理。

Effect of Different Irrigation Methods on Soil Organic Matter and Nitrogen Forms in Protected Field

The effects of different irrigation methods(subsurface irrigation,drip irrigation and furrow irrigation) on soil N forms and its profile distribution were studied in a protected field by determining the content of soil organic matter,total N,inorganic N and soil organic N.The same irrigation experiment was conducted for seven years and soils were sampled at different depths within 0-80cm.The result showed that soil organic matter changed from 8.47 to 36.48 g kg-1.The change of soil organic matter in soil profile was similar in subsurface irrigation and drip irrigation,however,great difference was found in furrow irrigation compared with other irrigation methods in 0-80cm soil layer.The content of soil organic matter in furrow irrigation was higher than that in subsurface irrigation and drip irrigation except at the depth of 30-40 cm.There are significant differences in soil total N and inorganic N at the depth of 0-20 cm with the highest content in subsurface irrigation,furrow irrigation secondly and drip irrigation thirdly.Soil total N,NO3——N,NH4+-N and organic N changed from 0.72 to 3.97 g kg-1,19.16 to 1442.06 mg kg-1,0 to 15.28 mg kg-1 and 683.79 to 2512.87 mg kg-1 respectively.Soil organic N was the highest in subsurface irrigation at the depth of 0-10 cm,the furrow irrigation was the next,and the drip irrigation was the last.But soil organic N was the highest in furrow irrigation at the depth of 10-30.