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Dr. agr. Kathlin Schweitzer

Lebenswissenschaftliche Fakultät · Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften · Lehr- und Forschungsstation Bereich Freiland

Projekte

Kooperationen

Themen

Bodenkunde Feldversuche Isotopenanalytik Klimaanpassung Längsschnittstudien Nachhaltige Landwirtschaft Nährstoffmanagement Pflanzenphysiologie Phosphorkreislauf Wasserspeicherung

Zusammenfassung

Dr. Schweitzer erforscht, wie landwirtschaftliche Managementpraktiken – insbesondere Unterbodenbearbeitung, Düngung und Kalkung – die Bodenfruchtbarkeit, Nährstoffverfügbarkeit und Kohlenstoffspeicherung beeinflussen. Ihr aktueller Fokus liegt auf der Anpassung von Böden an Trockenheit und Nährstoffmangel durch gezielte Unterbodenlockerung und organische Substanzeinbringung, um Wurzelwachstum und Ertragsresilienz unter Klimastress zu verbessern. Sie nutzt Langzeitfeldversuche und Isotopenanalytik, um zu verstehen, wie Phosphor und andere Nährstoffe in Bodenprofilen zirkulieren und wie Managemententscheidungen Wasser- und Nährstoffverfügbarkeit für Pflanzen regulieren. Ihre Erkenntnisse sind für Ackerbaubetriebe relevant, die unter Trockenheit und Bodenverdichtung leiden, sowie für die Wasserschutzpolitik, da sie zeigt, wie Düngung und Bodenbearbeitung Nährstoffausträge in Gewässer beeinflussen.

Matches

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Stammdaten

Identität, Organisation und Kontakt aus HU-FIS.

Dr. agr. Kathlin Schweitzer

HU-FIS-Profil ↗

Fakultät: Lebenswissenschaftliche Fakultät
Institut: Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften
Arbeitsgruppe: Lehr- und Forschungsstation Bereich Freiland
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Forschungsprojekte

Bodenbewertung für die nachhaltige Landnutzung hinsichtlich einer effektiven Phosphordüngung und der Verminderung des P-Eintrages in Gewässer
Quelle ↗
Förderer: Bundesministerium für Forschung, Technologie und Raumfahrt Zeitraum: 08/2002 - 07/2005 Projektleitung: Dr. agr. Kathlin Schweitzer
Risk of phosphate losses influenced by fertilisation in agricultural soils of Brandenburg / Germany
Quelle ↗
Förderer: Land Brandenburg Zeitraum: 10/2006 - 03/2010 Projektleitung: Dr. agr. Kathlin Schweitzer
BonaRes -(Modul A, Phase 2): Soil 3- II - Nachhaltiges Unterbodenmanagement, Teilprojekt G
Quelle ↗
Förderer: Bundesministerium für Forschung, Technologie und Raumfahrt Zeitraum: 10/2018 - 01/2022 Projektleitung: Prof. Dr. Timo Kautz, Dr. agr. Kathlin Schweitzer

Publikationen

12Auswahl der wichtigsten Publikationen — Quelle: OpenAlex.

Subsoil phosphorus is affected by fertilization regime in long‐term agricultural experimental trials
2018
European Journal of Soil Science · DOI
Summary 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 ( δ 18 O 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 Gießen. The NK treatments showed significantly smaller subsoil δ 18 O 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. Highlights Long‐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 plots Elevated δ 18 O HCl‐P in the subsoil of NPK plots indicates effects by enzymatic activity Small δ 18 O HCl‐P values in the subsoil of NK plots indicate a predominance of primary minerals
Crop response to P fertilizer omission under a changing climate - Experimental and modeling results over 115 years of a long-term fertilizer experiment

Subsoils—a sink for excess fertilizer P but a minor contribution to P plant nutrition: evidence from long-term fertilization trials

2021

Environmental Sciences Europe · DOI

Abstract Background The phosphorus (P) stocks of arable subsoils not only influence crop production but also fertilizer P sequestration. However, the extent of this influence is largely unknown. This study aimed to (i) determine the extent of P sequestration with soil depth, (ii) analyze P speciation after long-term P fertilization, and (iii) compare soil P tests in predicting crop yields. We analyzed four long-term fertilizer trials in Germany to a depth of 90 cm. Treatments received either mineral or organic P, or a combination of both, for 16 to 113 years. We determined inorganic and organic P pools using sequential extraction, and P speciation using 31 P nuclear magnetic resonance (NMR) and X-ray absorption near edge structure (XANES) spectroscopy. In addition, we applied three P soil tests, double-lactate (DL), calcium acetate lactate (CAL), and diffusive gradients in thin films (DGT). Results The results suggested that plants are capable of mobilizing P from deeper soil layers when there is a negative P budget of the topsoil. However, fertilization mostly only showed insignificant effects on P pools, which were most pronounced in the topsoil, with a 1.6- to 4.4-fold increase in labile inorganic P (P i ; resin-P, NaHCO 3 –P i ) after mineral fertilization and a 0- to 1.9-fold increase of organic P (P o ; NaHCO 3 –P o , NaOH–P o ) after organic P fertilization. The differences in P o and P i speciation were mainly controlled by site-specific factors, e.g., soil properties or soil management practice rather than by fertilization. When modeling crop yield response using the Mitscherlich equation, we obtained the highest R 2 ( R 2 = 0.61, P < 0.001) among the soil P tests when using topsoil P DGT . However, the fit became less pronounced when incorporating the subsoil. Conclusion We conclude that if the soil has a good P supply, the majority of P taken up by plants originates from the topsoil and that the DGT method is a mechanistic surrogate of P plant uptake. Thus, DGT is a basis for optimization of P fertilizer recommendation to add as much P fertilizer as required to sustain crop yields but as low as necessary to prevent harmful P leaching of excess fertilizer P.

Themen

Zusammenfassung

Matches

Stammdaten

Forschungsprojekte

Bodenbewertung für die nachhaltige Landnutzung hinsichtlich einer effektiven Phosphordüngung und der Verminderung des P-Eintrages in Gewässer

Risk of phosphate losses influenced by fertilisation in agricultural soils of Brandenburg / Germany

BonaRes -(Modul A, Phase 2): Soil 3- II - Nachhaltiges Unterbodenmanagement, Teilprojekt G

Publikationen

Subsoil phosphorus is affected by fertilization regime in long‐term agricultural experimental trials

Crop response to P fertilizer omission under a changing climate - Experimental and modeling results over 115 years of a long-term fertilizer experiment

Subsoils—a sink for excess fertilizer P but a minor contribution to P plant nutrition: evidence from long-term fertilization trials