不同氮源处理对红松苗木根际pH及养分有效性的影响

用根垫法研究了不同形态氮源对红松苗木根际pH及养分有效性的影响。结果表明,铵态氮处理使根际pH降低,硝态氮处理使根际pH升高。pH变化的方向与幅度主要取决于氮源及其浓度,且在同一浓度时铵态氮处理使根际pH下降的幅度大于硝态氮处理使根际pH升高的幅度。受根际pH变化的影响,铵态氮处理使苗木根际微量元素Fe、Mn、Cu、Zn的有效性增加,硝态氮处理则使根际Fe、Mn、Cu、Zn的有效性降低,而两种氮源处理对根际Ca、Mg有效性的影响均不大。

The Effects of Different Nitreon Sources on pH and the Nutrient Availability in the Rhizosphere of Korean Pine

The effects of different nitrogen sources on pH and nutrient availability in the rhizosphere of korean pine(Pinus koraiensis) were studied by means of root-mat method.The result showed that the addition of NH~ _4-N decreased the rhizosphere pH value,while the addition of NO~-_3-N increased the rhizosphere pH in contrast with the controled treatment.The direction and extent of the pH change mainly depended on the nitrogen sources and their concentrations applied,and at the same concentration,the extent to which the pH decreased as response to the addition of NH~ _4-N was bigger than that the pH increased as response to the addition of NO~-_3-N.The rhizosphere pH change,as affected by different nitrogen sources,had a remarkable influence on the availability of the micronutrients in the rhizosphere.The addition of NH~ _4-N increased the availability of Fe,Mn,Cu,Zn in the rhizosphere,whereas the addition of NO~-_3-N decreased the availability of Fe,Mn,Cu,Zn in the rhizosphere.However,the addition of both NH~ _4-N and NO~-_3-N had little effects on the availability of Ca and Mg in the rhizosphere.