ISSN:
1432-0789
Keywords:
Nitrogen fixation (C2H2 reduction)
;
Aerobic and N2-fixing heterotrophs
;
Photosynthetic purple nonsulphur bacteria
;
Straw
;
Wetland rice soil
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The effects of incorporation and surface application of straw to a wetland rice field on nitrogen fixation (C2H2 reduction), bacterial population and rice plant growth were studied. Rice straw (5 t ha−1) was chopped (10- to 15-cm pieces) and applied to the field 2 weeks before transplanting IR42, a long-duration variety, and IR50, a short-duration variety. The acetylene-reducing activity (ARA) of IR42 and IR50 measured at heading stage for 3 consecutive days showed significantly higher ARA in IR42 as a result of the 2 straw application methods. Mostly up to 20 days after straw surface application and incorporation, the dark ARA in the soil, total and N2-fixing heterotrophs, and photoorganotrophic purple nonsulphur bacteria (POPNS) in the soil and in association with degrading straw were stimulated. Higher bacterial populations were associated with straw on the surface than with straw incorporated. The POPNS counts, in particular, were increased hundreds fold in the surface-applied straw treatment. Straw applications also increased the root, shoot and total plant biomass at heading stage and the total dry matter yield at harvest in both varieties. The data show the potentials of straw as a source of substrate for the production of microbial biomass and for the non-symbiotic N2 fixation to improve soil fertility and plant nutrition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00257643
