Journal article

Publication year: 2018

Pages: 103-112

Journal: European Journal of Soil Science

Volume number: 69

Issue number: 1

ISSN: 1351-0754

DOI Link: https://doi.org/10.1111/ejss.12516

Publisher: Wiley

Abstract: 
Arable subsoils store large amounts of phosphorus (P); however, it is unclear to what extent, and under which conditions, subsoil resources might supplement crop P acquisition. Here, we hypothesized that (i) insufficient supply of P in topsoil promotes P acquisition from subsoil and (ii) subsoil P cycling is regulated by nitrogen (N) supply. We sampled two German long-term fertilizer trials in Thyrow (sandy soil) and Giessen (loamy-clayey soil) to 100-cm depth. Treatments received either NPK, NK or PK fertilizer for > 60 years. We assessed soil inorganic (P-i) and organic (P-o) P pools following Hedley sequential extraction, and the oxygen isotopic composition of HCl-extractable phosphate (delta O-18(HCl-P)), which differentiates P from primary and secondary (previously biologically cycled) minerals. We found that in the Hedley sequential extraction subsoil resin-P stocks (30-100 cm) in NK plots were 60% (Thyrow) and 8% (Giessen) less than those in NPK plots. Subsoil HCl P-i stocks in NK exceeded those of NPK plots by 70% in Thyrow, but not in Gieaen. The NK treatments showed significantly smaller subsoil delta O-18(HCl-P) values than NPK treatments, indicating a predominance of primary (not biologically cycled) minerals and refuting our hypothesis that P deficiency promotes P acquisition from primary minerals. Under N-limiting conditions, subsoil resin-P stocks exceeded those under NPK fertilizer by 117% (Thyrow) and 22% (Giessen), supporting our second hypothesis. We conclude that an efficient use of subsoil P resources is achieved only when nutrient supply in arable topsoils is sufficient.HighlightsLong-term N and P fertilization promotes use of P from subsoil (> 30-cm depth)Subsoil stocks of resin P were less in NK than NPK fertilized plotsElevated delta O-18(HCl-P) in the subsoil of NPK plots indicates effects by enzymatic activitySmall delta O-18(HCl-P) values in the subsoil of NK plots indicate a predominance of primary minerals

Harvard Citation style: Bauke, S., von Sperber, C., Tamburini, F., Gocke, M., Honermeier, B., Schweitzer, K., et al. (2018) Subsoil phosphorus is affected by fertilization regime in long-term agricultural experimental trials, European Journal of Soil Science, 69(1), pp. 103-112. https://doi.org/10.1111/ejss.12516

APA Citation style: Bauke, S., von Sperber, C., Tamburini, F., Gocke, M., Honermeier, B., Schweitzer, K., Baumecker, M., Don, A., Sandhage-Hofmann, A., & Amelung, W. (2018). Subsoil phosphorus is affected by fertilization regime in long-term agricultural experimental trials. European Journal of Soil Science. 69(1), 103-112. https://doi.org/10.1111/ejss.12516