| dc.description | Rice (Oryza sativa L.) is the staple food of over 40% of the world’s population
making it the most important food crop currently produced (Hossain and
Fischer, 1995). It is the major food for over two billion Asian people and for
hundreds of million in Africa and Latin America. Among the rice growing
countries, Bangladesh ranks third in area and fourth in production (Islam and
Diamond, 2000). Here about 26.62 million acres were used for its cultivation
where 25.19 million m tons of rice were harvested during 2002-2003 (BBS,
2004). Of the total rice production in the country, about 49% comes from boro
and the rest 44 and 7% from aman and aus, respectively (BBS, 2004).
Unfortunately, her average rice yield is less compared to agriculturally advanced
rice growing other countries like China, Japan, Korean Republic and the USA
(FAO, 2001). | en_US |
| dc.description.abstract | A study was undertaken to evaluate the combined effects of organic and inorganic fertilizers on
the indigenous Azotobacter and cyanobacterial population in soil and on the growth and yield of
rice for the Boro-fallow-T. aman rice cropping pattern. The study was carried out both at the
field and the laboratory of the Department of Soil Science, Hajee Mohammad Danesh Science
and Technology University, Dinajpur. In the field experiment, BRRI dhan28 (boro) and
Kataribhog (aman) were grown following the rice-rice cropping pattern in the two consecutive
years of 2009 and 2010 in Piedmont soil (AEZ#1). The study was initiated in November 2008
and was continued up to January 2011 to complete two crop cycles with boro rice (BRRI
dhan28) as the first crop and T. aman rice (Kataribhog) as the second crop in each cycle. The
experiment was laid out in the randomized complete block design (RCBD) with eleven
treatments having three replications. The 11 treatment combinations consisting of N, P, K, S, Zn,
cowdung (CD), poultry manure (PM) and mustard oil cake (MOC) including one control
treatment were as follows- To : Control, T; : 100 % RFD on the soil test basis, T, : 75%
RFD+25% CD, T3 : 50% RFD+50% CD, Ty : 75% RFD+25% PM, Ts; : 50% RFD+50% PM, Ts :
75% RFD+25% MOC, T; : 50% RFD+50% MOC, Ts : 75% RFD+25 % (CD, PM, MOC), Ty :
50% RFD+50% (CD, PM, MOC) and Tio : 34% CD + 33% PM + 33% MOC. Data were
recorded on yields, yield components and N, P, K and S contents and uptake by the grain and
straw of rice. In the laboratory indigenous cyanobacterial and Azotobacter population in soil
under study were determined before transplantation, 30 and 60 days after transplanting (DAT)
and after harvest of rice crops. Soil organic matter status, total N, available P, S and
exchangeable K of soil were also determined at 30 and 60 DAT and after harvest of rice crop to
assess the nutrient dynamics due to impose of different treatments. The results of the present
investigation indicated that integration of organic and inorganic fertilizers significantly
influenced the yield and yield components of rice, indigenous cyanobacterial and Azotobacter
population in soil and soil chemical properties. Results showed that the highest grain yields of
boro rice of 6.09 and 5.75 and those of straw of 6.86 and 7.65 t ha’! were recorded in treatment
Ts having 75% chemical fertilizer and 25% organic manures during boro seasons of 2009 and
2010, respectively. The lowest grain yields of 3.15 and 2.82 and those of straw yields of 3.88 and
3.37t ha were recorded in T, during 2009 and 2010, respectively. The highest grain yields of T.
aman rice of 5.40 and 4.90 and those of straw yields of 10.21 and 11.21t ha’! were recorded in Ts
during T. aman seasons of 2009 and 2010 respectively. The lowest grain yields of T. aman rice
of 2.78 and 2.28 and those of straw yields of 4.67 and 5.67t ha’! were found in T, during 2009
and 2010, respectively. The yield components viz. plant height, tillers hill’, panicle length,
grains panicle’ and 1000 grain weight were significantly affected by the treatments and the
maximum values were recorded in treatment Ts. The highest N, P, K and S contents and uptake
by rice were recorded in treatment Ts. Cyanobacterial and Azotobacter population was
significantly affected by the treatments. Higher cyanobacterial population was recorded in 2010
than those were observed in 2009. On the contrary, cyanobacterial population was higher in boro
season than those were recorded in T. aman season of the same year. Similar pattern of
Azotobacter popular was recorded during the entire period but the population was higher in boro
season than those of T. aman season. Soil organic matter and nutrient status such as total N,
available P, S and exchangeable K were slightly increased due to experimentation. From the
overall results, it can be concluded that integration of organic and inorganic fertilizers can save
25% chemical fertilizer without any yield decline. | en_US |
