Quantification of ammonia exchange between agricultural cropland and the atmosphere: Measurements over two complete growth cycles of oilseed rape, wheat, barley and pea

摘要: The exchange of ammonia between the atmosphere and canopy barley, wheat, oilseed rape pea crops was studied over two growing seasons by use a modified aerodynamic gradient technique in which passive horizontal flux samplers were applied with wind profile configuration. crop foliage net source NH3 to atmosphere, emissions on seasonal basis 1 5 kg NH3–N ha−1. amount lost constituted 4% nitrogen actual present mature shoots. volatile losses depended variations climatic conditions affecting growth economy increased under excessive N absorption roots high concentration foliage. accumulated loss positively correlated above-ground content at anthesis, but not that final maturity. There no indications larger unfavourable for remobilization from vegetative plant parts (low harvest index). Nevertheless, distinct peak emission occurred during senescence. It is concluded many areas will represent significant input may become large enough significantly affect budgets.