青藏高原不同株龄紫穗槐根际与非根际土壤养分变化特征

选取西藏拉萨人工种植的紫穗槐(Amorpha fruticosa),于2010-2012年分别对其1龄、2龄、3龄植株连续3年监测根际非根际土壤全氮、全磷、有机碳、硝态氮、铵态氮、pH和速效磷含量变化,结果表明,1)1龄和2龄根际土壤所有测定指标均表现出了根际正效应,而3龄除pH、速效磷外,其余指标均未表现出明显的根际正效应。2)根际和非根际全氮、全磷变化不明显。3)根际和非根际硝态氮、铵态氮含量随着种植年限的增加而逐渐增加;pH和速效磷则逐年减小。4)根际和非根际有机碳的变化表现为前两年逐年增加,第3年则根际减小而非根际仍在增加。5)根际全磷与全氮、速效磷呈极显著正相关(P0.01);pH与铵态氮呈显著负相关(P0.05),与速效磷呈显著正相关;铵态氮与硝态氮呈显著正相关。6)非根际硝态氮与铵态氮呈显著正相关,与pH、速效磷呈显著负相关;pH与铵态氮呈显著负相关,与速效磷呈显著正相关。

Effects of Amorpha fruticosa planting on soil nutrient characteristics at rhizosphere andnon-rhizosphere in Tibetan Plateau

The soil nutrients of Amorpha fruticosa cultivated in Lhasa, Tibet were measured in continuous three years from 2010-2012 when the plants were 1-year-age, 2-year-age and 3-year-age, respectively. The test indices included total nitrogen, total phosphorus, soil organic carbon, nitrate nitrogen, ammonium nitrogen, pH and available phosphorus from the rhizosphere and bulk soil. The results indicated that all parameters of the 1-year-age and 2-year-age A.fruticosa showed the positive rhizosphere impacts. However, all parameters except with pH and available phosphorus of the 3-year-age A. fruticosa didn’t show positive rhizosphere impacts. There was no significant variation of soil total nitrogen and phosphorus in rhizosphere and bulk. With the extension of cultivation years, the nitrate nitrogen and ammonium nitrogen of both rhizosphere and bulk soil increased, however, the pH values and available phosphorus decreased. The organic carbon of bulk soil increase with the extension of cultivation years, however, the organic carbon of rhizosphere soil increase in the second year and decrease in the third year. The total phosphorus of rhizosphere soil had a extremely significant positive correlation with total nitrogen and available phosphorus (P0.01). The pH values of rhizosphere soil had a significant negative correlation with the ammonium nitrogen (P0.05) and had a significant positive correlation with available phosphorus (P0.05). The ammonium nitrogen of rhizosphere and bulk soil had a significant positive correlation with the nitrate nitrogen (P0.05). The ammonium nitrogen of bulk soil had a significant negative correlation with the pH values and available phosphorus (P0.05). The pH values of bulk soil had a negative correlation with ammonium nitrogen (P0.05) and a positive correlation with available phosphorus (P0.05).