کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2025168 | 1069984 | 2011 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Phosphate additions have no effect on microbial biomass and activity in a northern hardwood forest Phosphate additions have no effect on microbial biomass and activity in a northern hardwood forest](/preview/png/2025168.png)
High rates of atmospheric nitrogen (N) deposition have raised questions about shifting patterns of nutrient limitation in northern hardwood forests. Of particular interest is the idea that increased supply of N may induce phosphorus (P) limitation of plant and microbial processes, especially in acid soils where P sorption by Al is high. In this study, we established field plots and plant-free laboratory mesocosms with P and Ca additions to test the hypotheses that 1) microbial biomass and activity are limited by P in the northern hardwood forest soils at the Hubbard Brook Experimental Forest in NH USA; 2) elevated Ca increases inherent P availability and therefore reduces any effects of added P and 3) P effects are more marked in the more carbon (C) rich Oie compared to the Oa horizon. Treatments included P addition (50 kg P ha−1), Ca addition (850 kg Ca ha−1) and Ca + P addition (850 kg Ca ha−1 and 50 kg P ha−1). The P treatments increased resin-available P levels and reduced phosphatase activity, but had no effect on microbial biomass C, microbial respiration, C metabolizing enzymes, potential net N mineralization and nitrification in the Oie or Oa horizon of either field plots or plant free mesocosms, in either the presence or absence of Ca. Total, prokaryote, and eukaryote PLFA were reduced by P addition, possibly due to reductions in mycorrhizal fungal biomass. These results suggest that increased N deposition and acidification have not created P limitation of microbial biomass and activity in these soils.
► Atmospheric N deposition may cause P limitation of forest soil microbial processes.
► P or P plus Ca had no effect on microbial parameters in the field or laboratory.
► P limitation is not likely in soils with significant pools of accessible P.
Journal: Soil Biology and Biochemistry - Volume 43, Issue 12, December 2011, Pages 2441–2449