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RICE EVALUATION TRIAL AT NAMULONGE
2005A
Results and discussion
Varieties performed
relatively well with an average yield of 5.4 t/ha. All varieties gave a
yield above average with exception of three varieties; WAB 880-14, WAB
880-29, WAB 880-21, NERICA 6 and NERICA 3 (Table 1). Hence there were no
significant differences observed in yield. Two varieties however, NARIC
1 which is the local check and NERICA 7 gave the highest yields of 7.0
and 6.9 t/ha. Related to yield was the 50% days to flowering where a
mean of 78.6 days was obtained. All varieties appear to have a similar
range of flowering date ranging between 76 and 79. The earliest of all
of them was NERICA 5 with 73.7 days followed by FOFIFA 4129 with only
74.7 days. NERICA 7 was the longest maturing variety with 88 days
followed by NERICA 1 (Table 1). The highest yielder, NARIC 1 was the
third in attaining 50% days to flowering. The mean obtained for panicle
length was 22.8 cm and the differences were not significantly different.
Variety FOFIFA 4355 had the shorted panicle measuring 20.7 cm followed
by NERICA 2 with 21.6 cm (Table 1). It was commonly observed that
varieties with long panicles had more grains but not all grains were
well filled. Since varieties showed significant differences in weight of
empty grains, it was felt important to estimated the loss due to poor
grain fill. Grain obtained from harvested area per plot was put in a
bucket of water and the poorly filled together with empty grains floated
while the well filled grain settled at the bottom. Well filled and empty
grains were dried and latter weight but each lot was handled separately.
The percentage of empty grain was obtained using the formula:
Grain loss= ((Weight of
well filled grain – Weight of empty grain)/Weight of well filled
grain)*100%
Varieties showed
significant (P=0.01) differences in grain loss due to poor filling/empty
grain, with WAB 880-21, which was one of the lower yielders gave the
highest grain loss of 33.0%, followed by WAB 880-14 which again was the
second lowest yielder. The lowest grain loss was obtained from five
varieties (NERICA 1, NERICA 6, NERICA 5, FOFIFA 4129 and NARIC 2) with a
range of 7.0 to 7.8%. Poor grain filling is usually attributed to bird
damage, drought at flowering, or abortion.
Analysis from
Pearson correlation showed a strong positive correlation between
percentage grain loss and weight of empty grains (Table 2). What it
means is that as the number of empty grains or weight of empty grains
continue going up, the yield loss increases. The other positive
correlation was observed between grain weight and culm length. The
longer the culm the longer it takes to attain 50% flowering as reflected
by a positive correlation.
YIELD PERFORMANCE OF 3
NERICAS ON FARMERS’ FIELDS
NARIC 3 which is
NERICA 4 is the only NERICA variety on market and therefore being grown
by farmers. It takes 120 days to mature as compared to some other
NERICAs which mature earlier. WARDA which developed NERICAs still has a
problem of raising enough seed to satisfy the demands of various
national programs, non-governmental organization and community based
organizations.
In this small
trial because of limited amount of seed, three NERICAs, namely NERICA 1,
NERICA 2, NERICA 4 and NERICA 5 plus 2 checks NARIC 1 and NARIC 2 were
evaluated on two farms in Masindi district. The trial was arranged in a
randomized complete block design with three replications. Each plot
measured 5 meters long with 6 rows. Fertilizer application and general
crop management was as in the above trial.
The average yield
on the 2 farms was 6.2 t/ha. The performance of the varieties was not
consistent. At Mr. Kisembo’s farm the yields were higher with NARIC 1
the local check giving the highest yield of 7.8 t/ha followed by NERICA
5 with 7.2 t/ha (Figure 1). While at Mr. Magona’s farm NARIC 2 gave the
highest yield of 6.5 t/ha followed by NERICA 1 with 6.4 t/ha. NARIC 1
which was the best at Mr. Kisembo’s farm was the fourth at Magona’s.
Overall, the NERICAs performed as equally good as the non- NERICAs. This
explains why some farmers prefer non- NERICAs like NARIC 1 and NARIC 2
as opposed to NARIC 3 (NERICA 4). Farmers should be encouraged to grow
varieties of their choice even if they are not NERICAs. From this work
also more seed for other trials like the Mother and Baby will be
obtained to enable putting up more trials.
RESPONSE OF RICE
VARIETIES TO LEVELS OF NITROGEN
Methodology
The response of rice
varieties was evaluated in the major rice growing districts of Luweero,
Masindi, Iganga, Wakiso and Mubende. Four varieties of rice; NARIC 1,
NARIC 2, NARIC 3 and Superica 2 were evaluated against 4 levels of
nitrogen: 0 kg N, 40 kg N, 80 kg N and 120 kg N/ha. Four trials were
established per district on farmers’ fields and during analysis each
farmer was considered a replication.
A reference trial was
established at Namulonge Research Institute whereby the four varieties
planted on-farm were also planted in a manner similar to when it was
planted on-farm. There was a drought in most of the districts at the
beginning of panicle development which reduced the effect of the
treatments. In Mubende district, the dry spell that started before
flowering continued until the end of the season to the extent that no
yield data was obtained. For instance at Namulonge Research Institute,
as shown in Figure 2, flowering occurred in May and rainfall was
characteristically low.
Results and discussion
Varieties did not
show any significant difference in the yield and noe were the nitrogen
levels (Table 3). All the rates of nitrogen applied significantly
increased the number of grains per panicle in all the 4 varieties
(P<0.001). However, application of 80 kg N resulted in the highest grain
number per panicle and 0 nitrogen had the lowest number of grains. There
was a significant difference in the number of grains per panicle among
the varieties with NARIC 3 and Superica 2 having the highest number of
grains per panicle. Besides, application of nitrogen at the rate of 80
kg N/ ha resulted in the longest panicle which was longer than in other
rates. NARIC 3 had the longest panicle which was significantly longer
than that of other varieties. Increasing nitrogen rate to 120kgN/ha
significantly decreased the panicle length.
ON FARM TRIALS
On farm trials
were established in to identify variety x nitrogen interactions and help
advise farmers on the rates to use for particular varieties. The results
from on-farm trials were analyzed for grain yield, the length of the
panicle and the grain number per panicle.
In Wakiso, the
highest yielding variety was NARIC 2 followed by NARIC 3 (Table 3).
There was little response to the applied nitrogen. The greatest response
was when 40 kg N/ha was applied.
There was a
slight reduction in yield when nitrogen was applied at the highest level
of 120 kg N/ha. The inversion of the yield due to application of high
nitrogen level could be associated with the observed delay in maturity
at the high nitrogen level which resulted in the crop being affected by
the dry spell more. This could be associated with the number of grains
per panicle.
In Luweero
district, the interaction between varieties and nitrogen levels was
significant although the main effect of nitrogen and varieties were not
significant (Table 4). The grain yield of NARIC 1 increased with
increasing nitrogen level up to 80 kg N/ha. Increasing nitrogen applied
to 120 kg N had the lowest yield. NARIC 2 had the lowest yield when
there was no nitrogen applied after which there was a small but
progressive decrease in yield with increasing rates of nitrogen.
The yield
response of NARIC 3 was similar to that of NARIC 2. Grain Yield of
Superica 2 was highest at 40 kg N /ha. There was a highly significant
difference among farms (replicates) and a highly significant farm x
variety interaction suggesting that other farm specific factors
interacted with the varieties.
The highest
number of grains per panicle was obtained when nitrogen was applied at
the rate of 40 kg N/ha. Increasing the level of nitrogen beyond 80 kg
N/ha depressed the number of grains per panicle. The reduction was
related to the unfilled spikelets as the panicle length was not as much
affected. All the varieties had similar number of grains per panicle
except for NARIC 1 which had a significantly lower number than the
others.
In Masindi,
application of 40 kg N/ha increased rice yield by 17 % and the
application of 120 kg N/ha increased the yield by 44% (6.92 t/ha vs.
4.80 t/ha) as indicated in Table 6. NARIC 3 and Superica 2 which are the
NERICA varieties had the lowest yield when nitrogen was not applied but
they had the best response to the low rate of 40 kg N per ha. To the
extent that their yields were similar to those of NARIC 1 and NARIC 2 at
this rate. Their yields were marginally higher at the highest rate of
nitrogen applied. The length of the panicle was only slightly
increased by the level of nitrogen applied.
RESPONSE OF
NERICA TO LEVELS OF NITROGEN, PHOSPHORUS AND POTASSIUM - NAARI 2005A
Background
Upland rice
production is a relatively new venture in the Ugandan farming. It is
being promoted when the nutrient status level of our soils is not
updated. The capacity of the soils to supply the macro-nutrients is not
known. There is also a possibility that the requirements of NERICA are
different from those of Oryza sativa suggesting that any
information about O. sativa might not be sufficient for Nerica
and yet most farmers in the country have shown interest for the new rice
It is therefore necessary to establish the fertility requirement of the
rice type as a recommendation to go with the varieties. Soil fertility
is location specific depending on the history of the field in relation
to the length of cropping after fallow and the overall management. It
will also depend on the inherent soil fertility of the field. There can
therefore be no data generated at a location that can be directly
applied to another location. Soils information therefore is best
generated at the farms within a region. Work carried out on-station,
however is necessary to establish the range within which to test on
farmers’ fields. It was against this background that the trial was
conducted on the response of NERICA to levels of N, P, and K at
Namulonge Research Institute.
Methodology
The performance
of NARIC 3 (NERICA 4) was evaluated at four nitrogen levels, 3
phosphorus levels and three levels of potassium at Namulonge Research
Institute during the 2005A season. The nitrogen levels were; 0, 40, 80
and 120 kg N/ha, phosphorus was applied at the rates of 0, 20 and 40 kg
P/ha and potash was applied at 0, 20 and 40 kg K/ha. The design was
randomized complete block with treatments in a factorial arrangement.
The nitrogen source was urea, phosphorus was supplied by triple Super
Phosphate (TSP) and Potassium was supplied by Muriate of potash.
Phosphorus was applied and incorporated in the seedbed before planting
and half the nitrogen and all the potassium were applied at three weeks
after planting the rice. The rest of the nitrogen was applied as side
dressing at 8 weeks after planting at about the time of maximum
tillering.
The individual
plot size was 3 m x 4 m. The weather was generally conducive for rice
production in the early part of the season. It was however dry during
the reproductive phase which is likely to have affected the number of
panicles per unit area and the number of spikelets per panicle. It was
however, better during the grain filling phase.
Results and
Discussion
There were
responses to the applied nutrient especially when nitrogen was applied
(Table 5). The results obtained indicate that there were no significant
differences among treatments. Some differences would have been expected
especially among nitrogen levels. The possible reason why the treatments
had no significant effect was related with the moisture stress during
the heading of the crop. Although NARIC 3 is fairly resistant to water
deficit stress, it is not resistant enough to severe moisture stress.
RESPONSE OF
RICE VARIETIES TO NITROGEN WHEN PLANTED AT DIFFERENT SEED RATES
Background
Rice, like many
species of the Poaecea (gramineae) family, has the capacity to tiller.
The tillering capacity is greatly influenced by the rice type, the
variety and the amount of nutrients especially nitrogen available to the
plant during the vegetative phase. The availability of a nutrient to the
plant depends on its availability in the soil and the number of plants
that compete for it. The tillering ability of upland rice varieties in
Uganda is not documented. It is also not known whether there is a
difference between the Oryza sativa and NERICA rice as regards
the tillering ability. Farmers plant rice in fields with varying soil
fertility and apply different levels of nutrient. The fertility of
fields decline after seasons of cropping. It is important to know the
response of varieties and/or types to fertility dynamics of the soil
with the changes and find ways to respond. The objective of the study is
to determine the response of rice types to nitrogen when the seed rate
varies.
Methodology
Two varieties of
rice were planted at four seed rates at Namulonge Research Institute.
They were subjected to four levels of nitrogen. The varieties planted
were NARIC 2 representing Oryza sativa and NARIC 3 representing
the Nerica type. They were planted at seed rates of 30, 60, 90 and 120
kg of seed per hectare. Nitrogen was applied to the rice at the rates of
0, 40, 80 and 120 kg of nitrogen per ha. One thousand seeds of NARIC 2
weighed 31 g and that of NARIC 3 weighed 27 g. The crop was planted in
rows 30 cm apart and the appropriate seed quantity was drilled into
shallow furrows and covered lightly with soil. It was planted on March
10, 2005 when it was assumed that the rains had become stable. The trial
was a factorial randomized complete block design in a split-split plot
arrangement with the varieties as the main plot, the nitrogen rates as
the sub-plot and the seed rates sub-sub plot. The individual plot was
1.5 m x 4 m. There was a slight moisture shortage at the beginning of
the season which had a negative effect on crop germination and
establishment, the rest of the vegetative phase except for a brief
moisture shortage about the time of flowering. The grain filling phase
had enough moisture for the crop. Data collected included; tiller count,
number of panicles per unit area and the grain yield and its components
Results
There was a
significant contribution of the dry spell at the time of panicle
formation on the yield outcome (Table 4a). NARIC 2 variety yielded 26 %
higher grain than NARIC 3 ( 5.03 t/ha compared with 3.99 t/ha) as per
table 4. NARIC 2 flowered about 10 days earlier than NARIC 3. NARIC 3 is
likely to have been affected by the dry spell than NARIC 2 which could
have escaped the severity of the dry spell. The trial needs to be
repeated to verify the results obtained. There was a significant
increase in yield associated with the application of nitrogen.
Application of 40 Kg of nitrogen increased grain yield by 36%. Nitrogen
application did not increase rice yield with higher rates of
application.
Application of
nitrogen affected the tiller production which was associated with the
variety (data not indicated). Planting rice varieties at different seed
rates and applying varying levels of nitrogen had a significant effect
on the number of tillers that survived to form panicles (Table 9). The
moisture stress at the time of flowering is likely to have an effect on
the number of tillers that headed thus affecting the number of panicle
per unit area.
In conclusion,
it can be said that the results obtained from the study suggest some
trends although they must have been influenced by the bad weather at the
time of heading. The trial will be repeated to confirm the results
obtained.
CHEMICAL WEED
CONTROL FOR RICE
Introduction
Weeds are a
major production constraint in rice production. This is especially so if
the weeds are grass weeds which look like rice in their seedling stage.
The rice seedling is weak and therefore not likely to compete with the
aggressive broadleaf weeds. Hand weeding is time consuming and laborious
and this tends to limit the farm size under rice for the smallholder
farmer using family labour. Some farmers have abandoned whole fields
because they cannot cope up with weeds. Others have used it as the
excuse to clear forests for rice production claiming that the crop is
less weedy if the land was virgin land (Plate 1). Though the use of
herbicides is likely to be expensive, it could be used by farmers who
would otherwise abandon rice production due to a lot of weeds. The
objective of the study was to evaluate the efficacy of herbicides in the
country that have been recommended for weed control in rice.
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