温度对土壤有效磷测定结果的影响

Effects of temperture on measurement of available phosphorus in soil

为了探讨显色温度对有效磷含量的影响,参照石灰性土壤有效磷的测定方法,在浸提过滤液中加入钼锑抗混合显色剂后,分别将恒温箱温度调至10、15、20、25、30℃,30min后用分光光度计在880nm波长下进行比色,测定其吸光值,然后计算有效磷的含量。结果表明:0～20cm和20～40cm土层的有效磷含量在显色温度为30℃最大,其次是25℃,但两者差异不大;温度为10、15、20℃时有效磷含量较低,并且与25℃和30℃时的测定值差异较大。显色适宜的温度应该为25～30℃。

In order to research the effects of temperature on content of the available phosphorus, according to determination method of available phosphorus in calcareous soil,after adding anti-Mo-Sb mixed reagent in the extraction filtrate, adjusting the incubator temperature to 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃, respectively, after 30 min, colorimetric method under 880 nm wavelength is carried on with a spectrophotometer, to determine ahsorhance values, and calculate the available phosphorus content. The results show that soil available phos- phorus content is the biggest at temperature of 30 ℃ in 0--20 cm and 20--40 cm soil layers,followed by the temperature is 25 ℃, but the difference of the available phosphorus content is small bewtten 25 ℃ and 30 ℃ , the available phosphorus content is low under the temperatures of 10 ℃, 15 ℃, 20 ℃ ,and there are significantly differences bewtten the tempertures of 10 ℃, 15 ℃, 20 ℃ and of 25 ℃ and 30 ℃. Therefore,the appropriate temperature should be 25 ℃--30 ℃.