ISSN:
1573-5036
Keywords:
Azolla
;
phosphorus
;
rice
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The trials to use Azolla as a green manure for rice culture were made in the Niger basin.Azolla pinnata (Niger isolate) was used for the experiments. The effect of phosphorus on the growth and N2-fixation was examined in the field and in the laboratory. The growth rate and N content were maximum with P 3.1 ppm culture solution under laboratory conditions. The threshold P content for the growth was 0.5–0.6% in the dry matter. Maximum N content was 4.1% in the laboratory culture. In the field culture, the effect of P fertilizer on the growth and N yield of Azolla was tested. The split application of 6.5 kg P ha−1 per 13 days was most effective in stimulating the growth of Azolla. One kg of P as triple superphosphate produced 3.66 kg N in the Azolla. Maximum growth rate and N content in the field trials was 4.3 days (doubling time) and 2.3%, respectively. The lower productivity in the field in comparison with the laboratory culture was considered to be due to higher temperature and light intensity. the growth of Azolla was suppressed in the hot season in the Niger basin. The growth rate and N content were reduced during the high temperature period over 30°C on an average. The effect of inoculation of Azolla on rice yield was tested in the field experiment. The grain yield was increased 27% by Azolla incolation over the treatment without Azolla inoculation in — N fertilizer treatments. While the growth of Azolla with rice plants did not attain saturated density (1.8 kg fresh weight m−2), the effect on the grain yield was comparable to 40 kg N ha−1 as urea.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02377065
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