ISSN:
1573-5036
Keywords:
growth response
;
inorganic fertilizer
;
Lactuca sativa L.
;
leaching loss
;
nitrogen
;
organic fertilizer
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The response of pot grown lettuce to inorganic (ammonium nitrate) and organic (dried blood and Protox) N fertilizers was determined at two temperature regimes (15°C day/10°C night and 20°C day/15°C night) and related to the NH4−N and NO3−N release characteristics of each material. The N release characteristics of the organic materials matched the N requirements of lettuce more closely than the inorganic fertilizer. However, was rapidly released from the protein based materials such that composts were depleted of available fertilizer N at the same time irrespective of the form supplied. The warmer temperature regimes resulted in a more rapid depletion of the fertilizers due to biological immobilization such that N recoveries in shoots, roots and leachates were reduced. Approximately 20% of the N present in Protox (a material derived from activated sewage sludge, processed to reduce the heavy metal content to minimal levels) appeared to be resistant to microbial degradation and was unavailable to the plants. Therefore, the growth response of lettuce was slightly reduced with Protox compared to the other materials at similar rates of incorporation. The organic materials did not contribute NO3−N to the plant and small NO3−N concentrations in petioles were derived from the water used for irrigation. However, NO3−N levels in plants receiving inorganic ammonium nitrate were initially high but progressively declined as the fertilizer NO3−N became depleted.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02220704
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