Central Rice Research Institute Annual report...2011-12

Enhancing and Sustaining the
Productivity of Rice Based
Farming Systems
Development of Integrated Nutrient
Management Technolo-gies for System
Productivity and Quality
Zero, reduced and optimum tillage for
improved soil physical condition and productivity
of rice based cropping system
A field experiment was conducted during wet season,
2011 to assess the effect of tillage practices under
different water regimes and tillage depth on soil physical
properties. The treatment consisted of dry (direct
seeded) and wet tillage (transplanted) in main plots;
shallow (tillage depth up to 10 cm) and deep (tillage
depth up to 18-22 cm) as sub plot treatment and FYM
and no FYM in sub-sub plot treatments in a split split
plot design with rice cv. Tapaswini.
Wet tillage recorded significant yield advantage of
0.6 t ha -1 over the dry direct seeded practice. The yield
was also significantly higher (0.14 t ha -1 ) in FYM treated
plots over no FYM. However, tillage depth had no significant
effect on yield. During dry season, greengram
cv. PDM 54 produced 48% higher yield in the plots
where dry direct sown rice was grown in the preceding
season.
In another experiment, the effect of zero tillage with
straw mulch was evaluated for establishment of dry
season crops in rainfed lowland. The treatment consisted
of three crops in main plots with three mulch
rates (rice straw at 0, 5 and 10 t ha -1 ) in sub plots. Mulching
at 5 and 10 t ha -1 significantly increased the yield of
greengram, groundnut and cowpea as compared to no
mulch treatment. It was also found that rice straw mulch
facilitated pod development of ground nut under zero
tillage condition and resulted higher seed yield.
Optimization of organic and inorganic sources
of nutrients for enhancing productivity and
GHGs emission
Effects of inorganic and organic nitrogen (N) management
on the emission of three major greenhouse
gases (GHGs) viz., methane (CH 4
), carbon dioxide (CO 2
)
and nitrous oxide (N 2
O), carbon equivalent emission
(CEE) and carbon efficiency ratio (CER) were investigated
in a flooded rice field. The treatments included
an unfertilized control, inorganic nitrogen fertilizer, rice
straw + inorganic nitrogen fertilizer and rice straw +
green manure. Maximum global warming potential
(GWP) (10188 kg CO 2
equivalent ha -1 ) and CER was
recorded in the field applied with rice straw and green
manure. The combined application of rice straw and
inorganic fertilizer was most effective in higher grain
yield and reduction of GHG emission (Table 27).
Table 27. Greenhouse gas emissions on seasonal basis and related parameters after the application of inorganic
fertilizers and organic manure to flooded soil planted with rice (cv. Gayatri)
Carbon
equivalent
Carbon
CH 4
CO 2
-C N 2
O-N GWP of emission efficiency
emission emission emission rice system (CEE) Yield ratio
Treatment (kg ha -1 ) (kg ha -1 ) (kg ha -1 ) (kg CO 2
ha -1 ) (kg C ha -1 ) (Mg ha -1 ) (CER)
Control 69.7a 1100.3a 0.23a 5862a 1599a 3.53a 0.95b
Urea 92.6b 1447.7b 1.00d 8084b 2205b 5.13b 1.00b
Rice straw + Urea 115.4c 1680.6c 0.84c 9418c 2568c 5.57b 0.93b
Rice straw + Green manure 122.7c 1858.5d 0.72b 10188d 2779d 5.30b 0.82a
[Note: In each column the mean values followed by common letters are not significantly (p