西藏“一江两河流域”农田土壤养分现状及分布特征

Current Situation and Distribution Characteristics of Farmland Soil Nutrients in‘One River and Two River Basins’of Tibet

以西藏“一江两河流域”农田土壤为试材,采用常规定量测验分析方法,研究了西藏“一江两河流域”主要农耕区农田土壤养分含量分布特征,以期为改善西藏“一江两河流域”农田土壤肥力状况,增强土壤的可持续性提供参考依据。结果表明:1)就土壤养分在垂直剖面上的分布而言,西藏“一江两河流域”农田土壤有机质、全氮、全磷和全钾含量均表现为0~20 cm>20~40 cm;2)就土壤养分在“一江两河流域”空间分布上而言,土壤有机质含量以浪卡子县(LKZ)最高,可达(61.59±8.29)g·kg^(-1),拉萨(LS)最低,其值为(26.19±4.09)g·kg^(-1);土壤全氮含量亦以LKZ最高为(1.57±0.37)g·kg^(-1),桑日县(SR)最低,LKZ较SR高出了112.16%;全磷含量以尼木县(NM)最高,其值为(11.58±3.34)g·kg^(-1),扎囊县(ZN)最低,仅为(4.39±1.41)g·kg^(-1);贡嘎县(GG)的土壤全钾含量最高,其值为(10.01±2.49)g·kg^(-1),朗县(LX)最低,GG较LX高出105.12%。显著性分析表明,除墨竹工卡县(MZGK)外,LKZ的农田土壤有机质含量显著(P<0.05)高于其它各样地,LKZ和白朗县(BL)的土壤全氮含量与达孜县(DZ)、GG和MZGK的土壤全氮含量之间差异达显著水平(P<0.05),与其它各样地之间的差异均达极显著水平(P<0.01),NM和曲松县(QS)的土壤全磷含量均显著高于其它各样地(P<0.05),GG、曲水县(QSH)和QS的土壤全钾含量除了与江孜县(JZ)、泽当(ZD)、BL和扎囊县(ZN)的土壤全钾含量之间差异不显著外(P>0.05),与其它样地之间差异均达显著水平(P<0.05)。综上可知,西藏“一江两河流域”农田土壤较贫瘠,在今后利用和管理过程中应加强对土壤养发的归还。

With the farmland soil in the‘One River and Two River Basins’of Tibet as test material,the distribution characteristics of farmland soil nutrient content in the main agricultural areas of the‘One River and Two River Basins’of Tibet were studied by using the conventional quantitative test and analysis method,in order to provide reference for improving the farmland soil fertility in the‘One River and Two Rivers Basin’of Tibet and enhancing the sustainability of the soil.The results showed that,1)in terms of the distribution of soil nutrients in the vertical profile,the contents of soil organic matter,total nitrogen,total phosphorus and total potassium in the farmland of‘One River and Two Rivers Basin’in Tibet were 0-20 cm>20-40 cm.2)In terms of the spatial distribution of soil nutrients in‘One River and Two River Basins’,the content of soil organic matter in Langjiaxian county(LKZ)was the highest,up to(61.59±8.29)g·kg^(-1),and Lhasa(LS)was the lowest,with a value of(26.19±4.09)g·kg^(-1).The total nitrogen content of soil was also the highest in LKZ(1.57±0.37 g·kg^(-1)),the lowest in Sangri county(SR),and LKZ was 112.16%higher than SR.The total phosphorus content in Nimu county(NM)was the highest,with a value of(11.58±3.34)g·kg^(-1),while that in Zhacao county(ZN)was the lowest,with a value of(4.39±1.41)g·kg^(-1).The content of total potassium in Gongga county(GG)was the highest,with a value of(10.01±2.49)g·kg^(-1),and Lang county(LX)was the lowest.GG was 105.12%higher than LX.The significance analysis showed that the content of soil organic matter in LKZ was significantly higher(P<0.05)than that in other places except MZGK,the difference of soil total nitrogen content between LKZ and Bailang county(BL)and Dazi county(DZ),GG and MZGK was significant(P<0.05),and the difference with other land was very significant(P<0.01),the content of total phosphorus in NM and Qusong county(QS)was significantly higher than that in other lands(P<0.05).Except that there was no significant difference between GG,Qushui county(QSH)and QS and that of Jiangzi county(JZ),Zedang(ZD),BL and Zabao county(ZN)(P>0.05),the difference between GG,Qushui county(QSH)and QS and other places was significant(P<0.05).To sum up,the soil fertility in Tibet′s‘One River and Two River Basins’lane system was low,in the future,the return of soil nutrients should be strengthened.