Fertilizer nitrogen recovery in long-term continuous winter wheat

• Published in: Soil Science Society of America journal Vol. 63; no. 3; pp. 645 - 650
• Main Authors: Raun, W.R, Johnson, G.V, Westerman, R.L
• Format: Journal Article
• Language: English
• Published: Madison, WI Soil Science Society of America 01-05-1999; American Society of Agronomy
• Subjects: Agriculture; Agronomy. Soil science and plant productions; application rate; Biological and medical sciences; continuous cropping; Crop production; efficiency; Fertilizers; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; grains; Nitrogen; nitrogen content; Nitrogen fertilization; nitrogen fertilizers; Nitrogen, phosphorus, potassium fertilizations; nutrient uptake; recovery; residual effects; soil; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Triticum aestivum; Wheat; wheat straw; Winter wheat; United States; North America; Oklahoma; America; Nitrogen fertilization; Monocotyledones; Isotope labelling; Long term test; Soil fertility; Cultivated soil; Cereal crop; Field experiment; Monoculture; Straw; Dose activity relation; Gramineae; Mineral fertilization; Angiospermae; Nitrogen fertilizer; Production system; Continuous cultivation; Grains; WINTER CROPS; Nutrient recovery; Nitrogen; Soil management; Residual effect; Ammonium nitrate; Spermatophyta; Soil plant relation; Triticum aestivum
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj1999.03615995006300030030x

Fertilizer N recovery in crop production systems seldom exceeds 50%. Two long-term winter wheat (Triticum aestivum L.) experiments were selected for use of (15)N to evaluate fertilizer recovery in the grain, straw, and soil. Each experiment included variable nitrogen rates that had been incorporated preplant each year for > 20 yr. In 1988, ammonium nitrate enriched with 11.888 atom % (15)N ((15)NH(4)(15)NO(3)) was applied to microplots within the main plots of these long-term experiments. Conventional ammonium nitrate (0.366% (15)N) was added to the microplots the following 2 yr to allow measurement of residual effects of the enriched fertilizer. Three years after the (15)N microplots were established, soil cores (0.025 m in diam.) were taken to a depth of 1.20 m and partitioned into 0 to 0.15, 0.15 to 0.30, 0.30 to 0.45, 0.45 to 0.60, 0.60 to 0.90, and 0.90 to 1.20 m. From all microplots, percentage (15)N recovered in the grain and straw at harvest and in the soil was determined and expressed as atom % excess corrected for background abundance. Total fertilizer N recovery ((15)N removed in the grain and straw plus that remaining in the soil) decreased with increasing N application at both locations. Results from this study combined with previously published findings from these locations suggest that fertilizer N recovery was greater where there was: (i) no evidence of priming (increased net mineralization of organic N pools when low rates of fertilizer N are applied); and (ii) reduced soil-plant buffering (N that can be applied in excess of the amount needed for maximum yield without resulting in increased soil profile inorganic N accumulation).