Controlled drainage is considered as a soil management tool to improve water supply to crops and reduce nutrient losses from fields; however, its closure may affect phosphorus (P) mobilization in soil. To assess the P mobilization potential, three soil profiles with redoximorphic features were selected along a slight hill in Northern Germany. Soil samples from three depths of each profile were characterized for basic properties, total element content, oxalate-and dithionite-extractable pedogenic Al, Fe and Mn Electronic supplementary material The online version of this article (

PNSS P150/5BSummaryÐZusammenfassung Knowledge of the spatial distribution of soil P forms in agricultural fields is important for evaluating the risk of P transfer to waterways. The objective of this study was to characterize the spatial variation of total P (P t ) and sequentially extracted P forms in the Ap horizon of arable soils at the field scale. Soil samples were taken on a regular grid of 50 m 50 m with 40 sampling points. Chemical analyses included basic soil properties, P t , sequentially extracted P forms, and acid phosphomonoesterase activity. The spatial variability was analyzed by geostatistics and descriptive statistics. The concentrations of P t ranged from 521 to 1020 mg kg ±1 with lower values observed for Gleysols and Stagnic Phaeozems and higher values for Luvisols and Cambisols. For the sequentially extracted P fractions, the largest coefficients of variation (c.v.) were found for NaHCO 3 -P o (41%), NaHCO 3 -P i (36%), NaOH-P o (34%), and resin-P (33%). Despite this great spatial variability, no spatial dependence could be proved by geostatistics because the calculated range of P forms (<10 m) was below the smallest sampling distance (50 m). A clear trend of increasing concentrations and proportions of organic NaHCO 3 -and NaOH-P fractions and phosphomonoesterase activity towards lower slope positions and the discharging brook indicated that Gleysols were a particular source of P losses to waterways in this catchment. It was concluded that these soils require a specific management with reduced P inputs and, perhaps, chemical treatment to fix leachable P.Key words: P fractions / arable soils / phosphomonoesterase Räumliche Variabilität sequenziell extrahierter P-Fraktionen in einem SchlufflehmKenntnisse über die räumliche Verteilung der P-Formen in landwirtschaftlichen Flächen sind notwendig für die Abschätzung des Risikos von P-Austrägen. Gegenstand dieser Untersuchung war die räumliche Verteilung von Gesamt-P (P t ) und P-Formen im Ap-Horizont von landwirtschaftlich genutzten Böden im Feldmaûstab. Dazu wurden Proben auf einem Raster von 50 m 50 m an 40 Punkten entnommen. Die chemischen Analysen umfassten Grundeigenschaften sowie P t , sequenziell extrahierte P-Formen und die Aktivität der sauren Phosphomonoesterase. Die räumliche Variabilität wurde mit räumlicher und deskriptiver Statistik untersucht. Die P t -Gehalte lagen im Bereich von 521 bis 1020 mg kg ±1 , wobei Gleye und Pseudogleye die niedrigsten Werte hatten. Bei den sequenziell extrahierten P-Fraktionen wurden die gröûten Variationskoeffizienten für NaHCO 3 -P o (41 %), NaHCO 3 -P i (36 %), NaOH-P o (34 %) und Harz-P (33 %) festgestellt. Trotz dieser groûen räumlichen Variabilität konnte mit Geostatistik keine räumliche Abhängigkeit nachgewiesen werden, möglicherweise weil die geschätzte Reichweite der P-Formen mit <10 m unterhalb der kleinsten Beprobungsdistanz von 50 m lag. Deutliche gerichtete Trends steigender Gehalte und Anteile organischer NaHCO 3 -und NaOH-P-Fraktionen und Phosphomonoesterase-Aktivitäten hin zu niedrigeren...

The production of plant-derived pharmaceuticals essentially requires stable concentrations of plant constituents, especially recombinant proteins; nonetheless, soil and seasonal variations might drastically interfere with this stability. In addition, variability might depend on the plant organ used for production. Therefore, we investigated the variability in plant constituents and antigen expression in potato plants under greenhouse and field growth conditions and in leaves compared to tubers. Using potatoes expressing VP60, the only structural capsid protein of the rabbit haemorrhagic disease virus (RHDV), CTB, the non-toxic B subunit (CTB) of the cholera toxin (CTA-CTB(5)) and the marker protein NPTII (neomycinphosphotransferase) as a model, we compare greenhouse and field production of potato-derived antigens. The influence of the production organ turned out to be transgene specific. In general, yield, plant quality and transgene expression levels in the field were higher than or similar to those observed in the greenhouse. The variation (CV) of major plant constituents and the amount of transgene-encoded protein was not influenced by the higher variation of soil properties observed in the field. Amazingly, for specific events, the variability in the model protein concentrations was often lower under field than under greenhouse conditions. The changes in gene expression under environmental stress conditions in the field observed in another event do not reduce the positive influence on variability since events like these should excluded from production. Hence, it can be concluded that for specific applications, field production of transgenic plants producing pharmaceuticals is superior to greenhouse production, even concerning the stability of transgene expression over different years. On the basis of our results, we expect equal or even higher expression levels with lower variability of recombinant pharmaceuticals in the field compared to greenhouse production combined with approximately 10 times higher tuber yield in the field.