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Ammonia Transport in a Temperate Grassland: I. Seasonal Transport in Relation to Soil Fertility and Crop Management
Author(s) -
Harper Lowry A.,
Bussink D. Wim,
Meer Hugo G.,
Corré Wim J.
Publication year - 1996
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1996.00021962008800040020x
Subject(s) - cycling , agronomy , temperate climate , fertilizer , environmental science , soil fertility , grassland , chemistry , soil water , biology , botany , soil science , archaeology , history
An understanding of N cycling in agricultural systems is necessary to optimize N‐use efficiency and reduce N losses to the environment. The objectives of this research were to evaluate N cycling in a highly fertilized grassland in a humid temperate climate and to observe the effects of N surplus and deficit on NH 3 absorption‐desorption by the grass. Soil, plant, and weather measurements were taken concurrently and soil‐plant‐atmosphere N transport were determined. After N application, soil inorganic N decreased rapidly to background levels, due to possible microbial immobilization and plant N demand. Much of the immobilized N was remobilized during the growth period, but at insufficient rates to avoid N stress by the crop, as shown by absorption of NH 3 . During spring, 45% of the plant N was derived from applied fertilizer, with the balance obtained from mineralized organic N (49%) and absorption of NH 3 (6%). During summer, fertilizer N accounted for 60% of accumulated grass N and NH 3 absorption accounted for 11% of N not derived from fertilizer (4% of the total N), with the balance coming from mineralized organic N. Soil water content and wind speed were the dominant factors influencing the crop NH 3 compensation point (CP). The daily NH 3 CP was variable, but the average seasonal NH 3 CP was about 14 μg m −3 .