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Nitrogen retention and plant uptake on a highly weathered central Amazonian Ferralsol amended with compost and charcoal
Author(s) -
Steiner Christoph,
Glaser Bruno,
Geraldes Teixeira Wenceslau,
Lehmann Johannes,
Blum Winfried E.H.,
Zech Wolfgang
Publication year - 2008
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200625199
Subject(s) - compost , charcoal , sorghum , leaching (pedology) , agronomy , chemistry , fertilizer , soil water , organic matter , biochar , slash and char , soil organic matter , nitrogen , crop , nutrient , environmental science , soil science , biology , pyrolysis , organic chemistry
Leaching losses of N are a major limitation of crop production on permeable soils and under heavy rainfalls as in the humid tropics. We established a field trial in the central Amazon (near Manaus, Brazil) in order to study the influence of charcoal and compost on the retention of N. Fifteen months after organic‐matter admixing (0–0.1 m soil depth), we added 15 N‐labeled (NH 4 ) 2 SO 4 (27.5 kg N ha –1 at 10 atom% excess). The tracer was measured in top soil (0–0.1 m) and plant samples taken at two successive sorghum ( Sorghum bicolor L. Moench) harvests. The N recovery in biomass was significantly higher when the soil contained compost (14.7% of applied N) in comparison to only mineral‐fertilized plots (5.7%) due to significantly higher crop production during the first growth period. After the second harvest, the retention in soil was significantly higher in the charcoal‐amended plots (15.6%) in comparison to only mineral‐fertilized plots (9.7%) due to higher retention in soil. The total N recovery in soil, crop residues, and grains was significantly ( p < 0.05) higher on compost (16.5%), charcoal (18.1%), and charcoal‐plus‐compost treatments (17.4%) in comparison to only mineral‐fertilized plots (10.9%). Organic amendments increased the retention of applied fertilizer N. One process in this retention was found to be the recycling of N taken up by the crop. The relevance of immobilization, reduced N leaching, and gaseous losses as well as other potential processes for increasing N retention should be unraveled in future studies.