ISSN:
1432-0789
Keywords:
Key words Cyanobacteria
;
Soil inoculation
;
N-transformation
;
Inorganic N
;
Easily oxidizable N
;
Hydrolysable N
;
Non-hydrolysable N
;
Wetland rice
;
Farmyard manure
;
Oryza sativa
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract A field experiment was conducted with wetland rice (Oryza sativa cv. IR-36) in a sandy clay loam soil (Entisol) to study the effect of inoculation with a soil-based mixed culture of four diazotrophic cyanobacteria, Aulosira fertilissima, Nostoc muscorum, N. commune and Anabaena spp., on the N-flux in inorganic (NH4 ++NO3 –+ NO2 –), easily oxidizable, hydrolysable and non-hydrolysable forms of N in soil during vegetative growth periods of the crop. Effects on grain and straw yield and N uptake by the crop were estimated. The effects of applying urea N and N as organic sources, viz. Sesbania aculeata, Neem (Azardirachta indica) cake and FYM, each at the rate of 40 kg N ha–1, to the soil were also evaluated. Inoculation significantly increased the release of inorganic N, evidenced by its increased concentrations either in soil or in soil solution. However, such increases rarely exceeded even 4% of total N gained in different froms in the soil system by inoculation during the vegetative growth stages of the rice plant, when the nutritional requirement of the plants is at a maximum. Most of the N2 fixed by cyanobacteria remained in the soil as the hydrolysable form (about 85%) during this period. Inoculation caused an insignificant increase in grain (8%) and straw (11%) yield, which was, however, accompanied by a significant increase in N uptake by the grain (30%) and an increase in total uptake of 15.3 kg N ha–1. Such beneficial effects of inoculation varied in magnitude with the application of organic sources, with farmyard manure (FYM) being the most effective. Application of urea N, on the other hand, markedly reduced such an effect.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01420232
Permalink
