Root growth and nitrogen uptake of carrot, early cabbage, onion and lettuce following a range of green manures

摘要: An experiment was performed to study the significance of rooting depth four vegetable crops on their utilization green manure nitrogen (N). Rates development were estimated as approximately 0.2, 0.7, 1.2 and mm day C)1 for onion, carrot, lettuce cabbage, respectively. At harvest, onion found be shallow-rooted with final depths only 0.3 0.6 m, respectively, whereas carrot cabbage reached at least 1.1 m. The two deep-rooted vegetables increased N uptake by 46, 24 7 kg ha)1 when following winterhardy legumes, non-hardy legumes rye, respectively; equivalent responses shallowrooted 23, 9 15 ha)1, Thus used legume more efficiently but made better use left non-legume rye crop. These interactions between type crop response are result dual effects manures: biological fixation legumes, variable ability green manure concentrate available in topsoil. Before crops, topsoil may important fixing legumes.