{"id":"https://openalex.org/A5080948612","orcid":"https://orcid.org/0000-0003-0609-2930","observed_orcids":["https://orcid.org/0000-0003-0609-2930"],"display_name":"N. Claassen","raw_author_names":["CLAASSEN, NORBERT","Claassen, N.","Claassen, Nicolaas","Claassen, Norbert","N Claassen","N. CLAASSEN","N. Claassen","Norbert Claassen"],"full_name":"Claassen, Nicolaas","works_count":208,"cited_by_count":5763,"summary_stats":{"2yr_mean_citedness":8.875,"h_index":41,"i10_index":78},"ids":{"openalex":"https://openalex.org/A5080948612","orcid":"https://orcid.org/0000-0003-0609-2930","observed_orcids":["https://orcid.org/0000-0003-0609-2930"]},"affiliations":[{"institution":{"id":"https://openalex.org/I110079840","ror":"https://ror.org/00b1c9541","display_name":"University of Hohenheim","country_code":"DE","type":"education","lineage":["https://openalex.org/I110079840"]},"years":[1990]},{"institution":{"id":"https://openalex.org/I114112103","ror":"https://ror.org/0304hq317","display_name":"Leibniz University Hannover","country_code":"DE","type":"education","lineage":["https://openalex.org/I114112103"]},"years":[1985,1982,1981]},{"institution":{"id":"https://openalex.org/I219193219","ror":"https://ror.org/02dqehb95","display_name":"Purdue University West Lafayette","country_code":"US","type":"education","lineage":["https://openalex.org/I219193219"]},"years":[1974]},{"institution":{"id":"https://openalex.org/I62916508","ror":"https://ror.org/02kkvpp62","display_name":"Technical University of Munich","country_code":"DE","type":"education","lineage":["https://openalex.org/I62916508"]},"years":[2001,1996,1995,1994,1993,1992]},{"institution":{"id":"https://openalex.org/I69552723","ror":"https://ror.org/00g0p6g84","display_name":"University of Pretoria","country_code":"ZA","type":"education","lineage":["https://openalex.org/I69552723"]},"years":[2026]},{"institution":{"id":"https://openalex.org/I74656192","ror":"https://ror.org/01y9bpm73","display_name":"University of G\u00f6ttingen","country_code":"DE","type":"education","lineage":["https://openalex.org/I74656192"]},"years":[2025,2022,2019,2017,2014,2013,2012,2011,2010,2009,2006,2005,2004,2003,2002,2001,2000,1999,1998,1997,1996,1995,1992,1991,1990,1989,1988,1986,1984]}],"last_known_institutions":[{"id":"https://openalex.org/I69552723","ror":"https://ror.org/00g0p6g84","display_name":"University of Pretoria","country_code":"ZA","type":"education","lineage":["https://openalex.org/I69552723"]}],"topics":[{"id":"https://openalex.org/T11247","display_name":"Plant nutrient uptake and metabolism","count":115,"subfield":{"id":"https://openalex.org/subfields/1110","display_name":"Plant Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T12294","display_name":"Agricultural Science and Fertilization","count":98,"subfield":{"id":"https://openalex.org/subfields/1111","display_name":"Soil Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T12754","display_name":"Plant Growth and Agriculture Techniques","count":93,"subfield":{"id":"https://openalex.org/subfields/1111","display_name":"Soil Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T12186","display_name":"Phosphorus and nutrient management","count":42,"subfield":{"id":"https://openalex.org/subfields/2311","display_name":"Waste Management and Disposal"},"field":{"id":"https://openalex.org/fields/23","display_name":"Environmental Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11418","display_name":"Plant Micronutrient Interactions and Effects","count":30,"subfield":{"id":"https://openalex.org/subfields/1110","display_name":"Plant Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}}],"topic_share":[{"id":"https://openalex.org/T11247","display_name":"Plant nutrient uptake and metabolism","value":0.0006438,"subfield":{"id":"https://openalex.org/subfields/1110","display_name":"Plant Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T12186","display_name":"Phosphorus and nutrient management","value":0.0005482,"subfield":{"id":"https://openalex.org/subfields/2311","display_name":"Waste Management and Disposal"},"field":{"id":"https://openalex.org/fields/23","display_name":"Environmental Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11418","display_name":"Plant Micronutrient Interactions and Effects","value":0.0002197,"subfield":{"id":"https://openalex.org/subfields/1110","display_name":"Plant Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T12294","display_name":"Agricultural Science and Fertilization","value":0.0001685,"subfield":{"id":"https://openalex.org/subfields/1111","display_name":"Soil Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T12754","display_name":"Plant Growth and Agriculture Techniques","value":0.0001386,"subfield":{"id":"https://openalex.org/subfields/1111","display_name":"Soil Science"},"field":{"id":"https://openalex.org/fields/11","display_name":"Agricultural and Biological Sciences"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}}],"x_concepts":[{"id":"185592680","wikidata":"https://www.wikidata.org/wiki/Q2329","display_name":"Chemistry","score":0.8245038986206055},{"id":"6557445","wikidata":"https://www.wikidata.org/wiki/Q173113","display_name":"Agronomy","score":0.8162575364112854},{"id":"86803240","wikidata":"https://www.wikidata.org/wiki/Q420","display_name":"Biology","score":0.7596983909606934},{"id":"39432304","wikidata":"https://www.wikidata.org/wiki/Q188847","display_name":"Environmental science","score":0.6527000069618225},{"id":"178790620","wikidata":"https://www.wikidata.org/wiki/Q11351","display_name":"Organic chemistry","score":0.14425358176231384}],"counts_by_year":[{"year":1974,"works_count":1,"oa_works_count":1,"cited_by_count":0},{"year":1975,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1977,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1981,"works_count":3,"oa_works_count":0,"cited_by_count":0},{"year":1982,"works_count":2,"oa_works_count":1,"cited_by_count":0},{"year":1984,"works_count":3,"oa_works_count":1,"cited_by_count":0},{"year":1985,"works_count":2,"oa_works_count":1,"cited_by_count":0},{"year":1986,"works_count":5,"oa_works_count":3,"cited_by_count":0},{"year":1987,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1988,"works_count":2,"oa_works_count":1,"cited_by_count":0},{"year":1989,"works_count":4,"oa_works_count":1,"cited_by_count":0},{"year":1990,"works_count":7,"oa_works_count":3,"cited_by_count":0},{"year":1991,"works_count":8,"oa_works_count":4,"cited_by_count":0},{"year":1992,"works_count":4,"oa_works_count":4,"cited_by_count":0},{"year":1993,"works_count":4,"oa_works_count":2,"cited_by_count":0},{"year":1994,"works_count":6,"oa_works_count":2,"cited_by_count":0},{"year":1995,"works_count":6,"oa_works_count":1,"cited_by_count":0},{"year":1996,"works_count":7,"oa_works_count":6,"cited_by_count":0},{"year":1997,"works_count":7,"oa_works_count":3,"cited_by_count":0},{"year":1998,"works_count":10,"oa_works_count":0,"cited_by_count":0},{"year":1999,"works_count":10,"oa_works_count":2,"cited_by_count":0},{"year":2000,"works_count":11,"oa_works_count":6,"cited_by_count":0},{"year":2001,"works_count":15,"oa_works_count":8,"cited_by_count":0},{"year":2002,"works_count":12,"oa_works_count":5,"cited_by_count":0},{"year":2003,"works_count":6,"oa_works_count":4,"cited_by_count":0},{"year":2004,"works_count":12,"oa_works_count":5,"cited_by_count":0},{"year":2005,"works_count":13,"oa_works_count":5,"cited_by_count":0},{"year":2006,"works_count":11,"oa_works_count":4,"cited_by_count":0},{"year":2007,"works_count":4,"oa_works_count":0,"cited_by_count":0},{"year":2009,"works_count":4,"oa_works_count":3,"cited_by_count":0},{"year":2010,"works_count":1,"oa_works_count":1,"cited_by_count":0},{"year":2011,"works_count":3,"oa_works_count":3,"cited_by_count":0},{"year":2012,"works_count":2,"oa_works_count":2,"cited_by_count":187},{"year":2013,"works_count":3,"oa_works_count":0,"cited_by_count":249},{"year":2014,"works_count":1,"oa_works_count":0,"cited_by_count":233},{"year":2015,"works_count":0,"oa_works_count":0,"cited_by_count":202},{"year":2016,"works_count":0,"oa_works_count":0,"cited_by_count":214},{"year":2017,"works_count":3,"oa_works_count":3,"cited_by_count":249},{"year":2018,"works_count":1,"oa_works_count":0,"cited_by_count":175},{"year":2019,"works_count":3,"oa_works_count":3,"cited_by_count":255},{"year":2020,"works_count":0,"oa_works_count":0,"cited_by_count":254},{"year":2021,"works_count":0,"oa_works_count":0,"cited_by_count":270},{"year":2022,"works_count":1,"oa_works_count":1,"cited_by_count":251},{"year":2023,"works_count":0,"oa_works_count":0,"cited_by_count":226},{"year":2024,"works_count":1,"oa_works_count":1,"cited_by_count":189},{"year":2025,"works_count":1,"oa_works_count":1,"cited_by_count":174},{"year":2026,"works_count":6,"oa_works_count":6,"cited_by_count":125}],"display_name_alternatives":["CLAASSEN, NORBERT","Claassen, N.","Claassen, Nicolaas","Claassen, Norbert","N Claassen","N. CLAASSEN","N. Claassen","Norbert Claassen"],"block_key":"n claassen","works_api_url":"https://api.openalex.org/works?filter=author.id:A5080948612","awards_count":0,"awards_api_url":"https://api.openalex.org/awards?filter=investigators.author.id:A5080948612","updated_date":"2026-11-11T13:02:13","created_date":"2016-06-24T00:00:00"}