Research article - Peer-reviewed, 1996
Measured and simulated nitrogen dynamics in winter wheat and a clay soil subjected to drought stress or daily irrigation and fertilization
Kätterer, Thomas; Andrén, OlofAbstract
The temporal dynamics of N in above- and below-ground parts of winter wheat and the dynamics of soil mineral-N were measured in the field in four treatments in wheat and a grass ley (L). The wheat treatments were: control (C), drought (D), daily irrigation (I), and daily irrigation and fertilization (IF). Nitrogen (20 g m(-2)) was supplied as single doses in spring in C, D, and I, and according to a logistic N uptake function in IF. L, which was under establishment, was irrigated and fertilized in the same way as IF, but the total amount applied was only 5.6 g N m(-2). A soil nitrogen simulation model, SOILN, was used to combine crop and soil N data with measured litter decomposition rates and other major parts of the nitrogen cycle to calculate annual N budgets, based on daily model calculations. The dynamic patterns of crop N uptake and soil mineral N were similar in C, D, and I, although different in magnitude, but different in IF. Plant N uptake in C, D, and I was almost nil after anthesis, whereas it continued in IF until harvest. Generally, simulated soil mineral N levels (0-90 cm) agreed reasonably well with measurements on a yearly time scale, whereas their short-term dynamics were less well described by the simulations. We tested the hypothesis that the short-term variations were due to processes not included in the model, i.e., the loss of recently taken up plant N via roots during the growing season, and microbial N immobilization and remineralization processes induced by root-derived carbon. A simulated input to the soil of 150 g C m(-2) in IF, mimicking root-derived C, resulted in an improved agreement between simulated and measured short-term mineral N dynamics. Because of irrigation, net N mineralization of soil organic material in I and IF was about twice that in C and D, while that in L was about three times higher due to irrigation and high soil temperatures. Simulated N leaching during the following winter was highest in L, followed by I, IE C and D. Measurements and simulations of N amounts in the system indicated that daily fertilization decreased N leaching compared with single-dose fertilization.Published in
Fertilizer Research1996, volume: 44, number: 1, pages: 51-63
Publisher: KLUWER ACADEMIC PUBL
Authors' information
Swedish University of Agricultural Sciences, Department of Soil Sciences
Andrén, Olof
Swedish University of Agricultural Sciences, Department of Soil Sciences
UKÄ Subject classification
Soil Science
Publication Identifiers
DOI: https://doi.org/10.1007/BF00750692
URI (permanent link to this page)
https://res.slu.se/id/publ/44539