ISSN:
1573-0867
Keywords:
Urea
;
apparent fertilizer N recovery
;
soil inorganic nitrogen
;
anion exchange capacity
;
corn
;
humid tropics
;
subsoil acidity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Nitrogen fertilization experiments were conducted on a Oxisol and Entisol in the Central Amazon to evaluate the influence of soil properties and rainfall distribution on soil inorganic N movement and N recovery by corn (Zea mays L.). One corn crop was grown during the wet season on each site. A second crop was planted in the Oxisol during the dry season. Inorganic N was monitored in urea-N treatments (0 to 160 kg ha−1) to a depth of 0.60 m by periodic soil sampling during each crop. During the wet season large N losses by leaching occurred in both soils with 120 or 160 kg ha−1 of applied N. Differences in soil permeability and corn rooting depth between soils contributed to a greater movement of N into subsoil layers in the Oxisol than the Entisol. However, N leaching beyond 0.60 m in the Oxisol was delayed, apparently because of NO 3 − adsorption in the net positively charged subsoil layers. Corn yields and N recovery in the Entisol were higher than in the Oxisol, during the wet season. During the dry season N leaching in the Oxisol was greatly reduced, relative to the previous wet season, by split applications of fertilizer N and lower cumulative rainfall (300 vs. 1012 mm). Management practices which promote root growth into acid subsoil layers of the Oxisol would increase plant access to soil N, improve crop N recovery and reduce fertilizer N requirements.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01063298
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