ISSN:
1573-5036
Keywords:
Brackish water alluvial soil
;
Crop-induced phosphate mobilization
;
Flooded soils
;
Immobilization
;
Resin extractable phosphate
;
Rhizosphere
;
Rice
;
Sandy loam soil
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Poor or lack of response of lowland rice to P fertilization is a well-known fact. Several studies were conducted in this direction however, our understanding regarding the underlying mechanism has been far from clear. A remarkable influence of rice plants on P transformation in submerged soil is identified in this experiment which may shed light on this problem. Accordingly, in presence of rice plants P was mobilized during the initial growing period followed by immobilization. The increased microbial activity in presence of physiologically active roots was responsible for P mobilization, while capacity of rice plants to reoxidize the rhizosphere, by secretion of oxygen from roots, during later growing period was responsible for P immobilization. The extent of P mobilization decreased while that of immobilization increased with increasing P levels in different soils. At a given P level the ratio of P mobilization to immobilization was higher in a soil where crop growth was better and P uptake was higher as compared to another soil where crop growth was poor with lower P uptake. Thus, lowland rice plants appear to possess an unique physiological mechanism, to regulate the contrasting changes in P availability in the rhizosphere depending on P requirement by the plants or P availability in soil, which in turn is responsible for the poor or lack of response to P fertilization. The experiment was conducted in a growth chamber. Two soils with widely varying properties were used.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02197948
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