Autoclaving soil samples affects algal-available phosphorus
Autoclaving soil samples affects algal-available phosphorus
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DOI：
10.2134/jeq2005.0024
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发表时间：
2005-11-01
影响因子：
2.4
通讯作者：
Magdoff, FR
中科院分区：
文献类型：
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作者：
Anderson, BH;Magdoff, FR
用于磷有效性生物测定的样品中不需要的微生物干扰通常在接种藻类之前通过高压灭菌来消除。选取了23种土壤，以评估含有少量土壤的缺磷溶液中藻类生长与各种用于评估土壤和沉积物中磷有效性的试验确定的磷水平之间的关系。土壤要么经过高压灭菌，要么没有经过高压灭菌，然后在不含磷的营养液中加入含有缺磷藻类的烧瓶。与未经过高压灭菌的样品相比，经过高压灭菌的土壤的有效磷含量增加了约60%，据藻类生长的增加估计。然而，在高压土壤中藻类的生长与在非高压样品中藻类的生长高度相关。在高压灭菌或非高压灭菌样品中，藻类数量与多次土壤试验提取的磷之间的相关性(r)没有一致的变化。对6种土壤进行高压灭菌对可溶性磷的影响也进行了评估。蒸压土壤的可溶性磷含量明显高于非蒸压土壤，正磷酸盐单酯含量高出78%，正磷酸盐二酯含量高出60%，可溶性无机磷含量高出54%。两种高锌土壤的藻类生长可能受到抑制，尽管所有提取方法估计的有效磷含量都很高，但藻类数量相对较少。将这些样本从计算中剔除后，通过各种方法测量的土壤磷含量与藻类生长之间的相关性显著提高。将这两种土壤从计算中剔除后，蒸压土壤中藻类生长与Olsen P关系最为密切（r = 0.95），其他相关关系如下：Fe-oxide strip （r = 0.80）、Mehlich 3 （r = 0.75）、modified Morgan （r = 0.61）和bry - kurtz 1 （r = 0.57）。
Unwanted microbial interference in samples used for biological assays of P availability has routinely been eliminated by autoclaving samples before inoculation with algae. Twenty-three soils were selected to evaluate the relationship between algal growth in P-deficient solutions containing small quantities of soil and the level of P determined by a variety of tests used to evaluate P availability in soils and sediments. Soils were either autoclaved or not before addition to flasks containing P-starved algae in a nutrient solution without P. Compared to non-autoclaved samples, autoclaving soil resulted in approximately 60% more available P as estimated by increased algal growth. However, algal growth in the presence of autoclaved soil was highly correlated with growth in the presence of non-autoclaved samples. There was no consistent change in the correlations (r) between autoclaving or non-autoclaving samples in the relationships of algal numbers with P extracted by a number of soil tests. The effect of autoclaving soil on soluble P was also evaluated for a subset of six soils. Autoclaved soils had significantly greater concentrations of soluble P than non-autoclaved soils, with 78% more orthophosphate monoesters, 60% more orthophosphate diesters, and 54% more soluble inorganic P. Inhibition of algal growth may have occurred with two high-Zn soils that produced relatively low numbers of algae despite being very high in estimated available P by all extraction methods. Removing those samples from the calculations dramatically improved correlations between soil P measured by various methods and algal growth. With these two soils removed from calculations, algal growth with autoclaved soil was most highly correlated with Olsen P (r = 0.95), with other correlations as follows: Fe-oxide strip (r = 0.80), Mehlich 3 (r 0.75,), modified Morgan (r = 0.61), and Bray-Kurtz 1 (r = 0.57).