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Effect of tillage, farmyard manure and potassium rates on the perfomance and profitability of cassava in selected districts of Kagera, Tanzania
No full textDissertationIn Tanzania cassava (Manihot esculenta, Crantz) is the second most important food
security crop after maize. Its roots produce at least 30% of starch on dry weight basis,
which is the major source of dietary energy, different industrial products like sugar,
pharmaceutics, alcohol, textile products and animal feeds. In the Lake zone of Tanzania,
cassava is grown in all regions, which account for 23.7% of the total cassava production in
the country. Despite the importance of cassava in food systems there is decreasing yield.
For example, the national average root yield is 10 MT ha -1 compared to the potential yields
of 25 - 80 MT ha -1 , whereas in Kagera region, average yield in farmers’ fields is about 7.80
MT ha -1 .
The low yield is due to, among others, increased susceptibility of the crop to cassava
mosaic disease (CMD) and cassava brown steak disease (CBSD), declining soil fertility
and poor agronomic practices. In the Lake zone, cassava is planted on ridges or on flat
tillage but little information exists on the performance of cassava when planted on ridges
or on flat tillage. In addition, cassava responds well to farmyard manure and inorganic
fertilizers. But scant information exists on the performance of cassava upon use of different
rates of FYM and potassium fertilizer, specifically based on Kagera region climate and
soils. This study, therefore, aimed to determine the effects of tillage methods and
application of different rates of FYM and potassium fertilizers on the performance and
profitability of cassava in Bukoba, Missenyi and Biharamulo districts of Kagera region.
The specific objectives of this study were to: (i) characterize and classify the soils of the
study area and assess their suitability for cassava production, (ii) assess the current soil
fertility status of farmers’ fields in the study sites, (iii) determine the effects of tillage
methods, farmyard manure and potassium rates on soil moisture conservation and relationship with cassava root yield, (iv) determine the effects of tillage methods, FYM and
potassium rates on cassava growth, yields and root quality, and (v) evaluate the economics
of using farmyard manure and potassium fertilizer rates in cassava production in the study
area.
To achieve objective i, pedological characterization, which involved reconnaissance field
survey in Bukoba, Missenyi and Biharamulo Districts was carried out. Soil profile
description and soil sampling for laboratory analysis were done according to the FAO
Guidelines for Soil Description. The soils of the study sites were classified to the family
level of the USDA Soil Taxonomy and to tier-2 of the FAO World Reference Base for Soil
Resources. Soil suitability assessment of the experimental sites was done using a simple
limitation method based on the FAO Framework for Land Evaluation. The results revealed
that the soils of Bukoba and Biharamulo sites had similar morphological properties, which
were different from Missenyi site. But all differed in their physical, chemical and generic
properties. Based on the USDA Soil Taxonomy, Bukoba and Biharamulo sites were
classified as “Typic Kandiudults”.and as “Haplic Ferralic Acrisols”, and “Chromic
Ferralic Acrisols” respectively according to FAO World Reference Base for Soil
Resources. Missenyi site was classified as “Typic Endoaquolls” and “Fluvic Gleyic
Phaeozems” according to USDA Soil Taxonomy and FAO World Reference Base for Soil
Resources, respectively. Moreover, Missenyi and Biharamulo sites were evaluated as
marginally suitable and the Bukoba site as moderately suitable for cassava production.
Therefore, soil fertility management strategies are recommended in each studied site for
optimum cassava yields.
To achieve objective ii, two wards and one village in each ward were selected in Bukoba,
Missenyi and Biharamulo districts. A total of thirty-three fields were selected (five farmers' fields in each village and one experimental field in each district). Composite soil samples
at 0- 20 cm depth were taken using a using a zigzag pattern over the whole field's area and
analyzed. Correlation analyses among soil chemical properties were performed using IBM
SPSS Statistic 20 statistical package. Soil fertility index (SFI) and identification of limiting
nutrients were used to assess the fertility status of selected farmers’ the fields. Results
indicate that the studied fields had poor fertility to good fertility. Phosphorus and
potassium deficiencies were widely spread in Bukoba district while N and S deficiencies
were widely spread in Missenyi district and N, P and K deficiencies were widely spread in
Biharamulo district. There were positive and negative and significant (p≤ 0.05) and highly
significant (p≤ 0.01) correlations among the soil chemical properties in each district.
Therefore, site specific soil fertility management practices are recommended based on
limiting nutrients.
To achieve objective iii, one cassava field trial was established in each selected district
(Bukoba, Missenyi and Biharamulo) during 2018/19 and 2019/20 cropping seasons using
the split-plot design. The treatments were arranged in Randomized Complete Block Design
(RCBD) with three replications. Tillage methods (flat tillage, open ridging and tied
ridging) were the main plots and fertilizer types and rates [farmyard manure (FYM) alone
at 4 MT ha -1 or FYM alone at 8 MT ha -1 , nitrogen (40 kg N ha -1 ) + phosphorus (30 kg P ha -
1
) + potassium at 40, 80 or 120 kg K ha -1 and the combination of FYM alone at 4 MT ha -1
or FYM alone 8 MT ha -1 + potassium at 40, 80 or 120 kg K ha -1 ] were the sub-plots. Soil
moisture was monitored starting from 1 week after the last rain event at an interval of 2
weeks up to the first rain event of the following season. The soil samples in cores were
weighed and placed in the drying oven at 105 o C to constant weight. The soil moisture
content (%) in each soil sample was determined gravimetrically. The results showed that
tie and open ridges conserved significantly (p≤0.05) more soil moisture ranging from 24 to 58% (Bukoba district), 10 to 45% (Missenyi district) and 10 to 32% (Biharamulo district)
than flat tillage ranging from 22 to 43% (Bukoba district), 8 to 37% (Missenyi district) and
7 to 27% (Biharamulo district) in both cropping seasons. However, tied ridges conserved
significantly (p≤0.05) more (11 to 58%) soil moisture than open ridges (10 to 47%) in the
medium and high rainfall areas as opposed to the low rainfall area. The results also indicate
that the use of FYM significantly (p≤0.05) conserved more soil moisture (16.54 to 63.48%)
than inorganic N, P and K fertilizers (12.27 to 53.60%). In addition, use of FYM alone at 8
MT ha -1 conserved significantly (p≤0.05) more soil moisture (19.94 to 62.16%) than FYM
alone at 4 MT ha -1 (16.80 to 58.33%). Moreover, there was a significant (p≤0.05)
association between soil moisture conservation and changes in cassava root yields.
Therefore, planting cassava on ridges together with use of high rates of FYM (8 MT ha -1 ) is
indispensable for adequate soil moisture conservation and improving cassava root yields.
To achieve objective iv, data on daily rainfall (mm) were collected in each experimental
site. Data on root and biomass yields (MT ha -1 ) were collected from the net plot from
established trials described in objective ii above. About 500 g of cassava roots from each
treatment were peeled and oven dried at 105 o C to constant weight for determining dry
matter content gravimetrically and root starch content in each treatment was determined. In
addition, the post-harvest soil samples and cassava leaf samples were collected from the
control plots and the plots that received the combination of FYM at 8 MT ha -1 and
potassium (K) at 40 or 120 kg ha -1 for determining the concentration of Nitrogen,
phosphorus and K and soil pH. The results indicate that planting cassava on ridges gave
significantly (p≤0.05) higher (18.98 - 34.84 MT ha -1 ) cassava fish root yield than on flat
tillage (16.86 - 29.74 MT ha -1 ). However, use of ridges or flat tillage did not show
significant (p≤0.05) difference in starch and dry matter contents in cassava roots, soil pH,
and concentration of N, P and K in the soil and cassava leaves and sprouting of cassava plant. Combined use of FYM at 4 MT ha -1 or FYM at 8 MT ha -1 and potassium at 40, 80 or
120 kg K ha -1 significantly (p≤0.05) improved cassava growth and increased cassava fresh
root yields (14.56 - 39.94 MT ha -1 ). Also, combined use of FYM at 4 MT ha -1 or FYM at 8
MT ha -1 and potassium at 40, 80 or 120 kg K ha -1 ; significantly (p≤0.05) improved cassava
growth and increased cassava fresh biomass yields (9.36 - 32.86 MT ha -1 ). Combined use
of FYM at 8 MT ha -1 and potassium at 120 kg K ha -1 or FYM at 8 MT ha -1 and potassium
at 40 kg K ha -1 increased the concentration N, P and K in the soil and N and K in cassava
leaves. Therefore, planting cassava on ridges and combined use of FYM at 4 MT ha -1 and
potassium at 80 or 120 kg K ha -1 is desirable for improving cassava growth, increasing
biomass and root yields and increasing root quality. Combined use of farmyard manure at
8 MT ha -1 and potassium at 120 kg K ha -1 is desirable for increasing the concentration of N
and K in the soil and in cassava leaves. However, for the resource-poor farmers who
cannot afford the high rate of K, combined use of farmyard manure at 8 MT ha -1 and
potassium at 40 kg K ha -1 can be used.
To achieve objective v, yields data collected from the established trials as described in
objective iii above were used to perform partial budget analysis, whereby, the gross values
were estimated using the adjusted yields at market price for cassava and fertilizers. Costs
and benefits were calculated on a hectare basis. All variable costs were summed up to give
total variable cost (TVC). Thereafter, the net benefits (NB) ha -1 of the tested treatments
were calculated and used to assess the profitability of each treatment. In addition, benefit-
cost ratios (BCR) of the tested treatments were compared to the acceptable value of greater
than 2 for the technology to be adopted by farmers. The results indicate that in both
cropping seasons, and at all studied sites, all tested fertilizer rates gave acceptable BCR of
greater than 2, implying that all the fertilizer types and rates tested in this study could be
used in cassava production in the study areas. In addition, the results on net benefit indicate that use of combination of FYM at 8 MT ha -1 and potassium at 80 kg K ha -1 gave higher net
benefit than the other fertilizer types and rates, and is therefore, desirable for increasing
cassava root yield and economic benefit in the study area. However, for the resource-poor
farmers, combined use of farmyard manure at 8 MT ha -1 and potassium at 40 kg K ha -1 can
still be adopted in the study area because, for some reason, not all the famers can afford the
best treatment.
The major conclusions drawn from this study are that the soils of Bukoba and Biharamulo
sites have similar morphological properties, which are different from Missenyi site.
However, all soils differ in their physical, chemical and generic properties. According to
the USDA Soil Taxonomy, the soils of both Bukoba and Biharamulo sites were classified
as “Typic Kandiudults” and as “Haplic Ferralic Acrisols” and “Chromic Ferralic
Acrisols”, respectively, according to FAO World Reference Base for Soil Resources. The
soil of Missenyi site was classified as “Typic Endoaquolls” according to USDA Soil
Taxonomy and as “Fluvic Gleyic Phaeozems” according to FAO World Reference Base for
Soil Resources. Missenyi and Biharamulo sites were both evaluated as marginally suitable
while Maruku site was evaluated as moderately suitable for cassava production due to soil
fertility constraints and hence sustainable cassava production in these areas would need
interventions for soil fertility improvement.
The soil fertility status of the studied fields ranged from poor fertility to good fertility
whereas, P and K deficiencies were widely spread in Bukoba district while N and S
deficiencies were widely spread in Missenyi district and N, P and K deficiencies were
widely spread in Biharamulo district. Use of ridges conserved more soil moisture than use of flat tillage, and use of farmyard
manure at 8 MT ha -1 conserved more soil moisture than combined use of inorganic N, P
and K fertilizers or use of farmyard manure at 4 MT ha -1 . Moreover, plating cassava on
ridges together with combined use of FYM at 4 MT ha -1 and potassium at 40, 80 or 120 kg
K ha -1 improved cassava growth and increases cassava root and biomass yields than use of
flat tillage together with the same fertilizer rates.
Combined use FYM at 8 MT ha -1 and potassium at 80 or 120 kg K ha -1 or combined use of
inorganic N at 40 kg ha -1 , P at 30 kg ha -1 and K at 120 kg ha -1 increased the contents of
starch and dry matter in cassava roots and combined use of FYM at 8 MT ha -1 and
potassium at 40 80, or 120 kg K ha -1 increased concentration of N, and K in the soil and
cassava leaves.
In terms of profitability, combined use of FYM at 8 MT ha -1 and potassium at 80 kg K ha -1
gave higher net benefit than the other fertilizer types and rates tested in this study and is
therefore, desirable for increasing cassava root yield and economic benefit in the study
area. However, for the resource-poor farmers, who cannot afford the best treatment,
combined use of farmyard manure at 4 MT ha -1 and potassium at 80 kg K ha -1 can still be
adopted.Alliance for Green Revolution in Africa (AGRA
Effect of phosphate rock placement methods and incorporation of organic residues on phosphorus availability and maize yields in two soils with different phosphorus fixing capacities
No full textDissertationA study was conducted under pot and field conditions to evaluate the effects of
Minjingu phosphate rock (MPR) placement methods and organic residues on MPR
dissolution, P availability and maize yields in two soils with different P fixing
capacities. Observations from two field experiments, one at Sasanda, Mbeya and
another at Magadu, Morogoro were continued to evaluate the effect of continued
addition of organic materials (OM) banded with MPR on MPR dissolution, P
availability and maize yields. One field experiment was carried out at Sasanda to
evaluate the effects of different rates of OM applied together with MPR on MPR
dissolution, P availability and maize yields. For the continued experiments, the
treatments tested were control, broadcasted MPR, 2 to 5 cm width strip banded MPR,
20-cm wide MPR band incorporated to 10 or 20 cm depth, and 20-cm MPR band +
O.M incorporated down to 10 or 20 cm depth. These were tested only in the field.
For the new experiment the treatments tested were control, broadcasted MPR, 2 to 5
cm width strip banded MPR, 20-cm wide MPR band incorporated to 20 cm, and 20-
cm band MPR + OM applied together at 2, 4, 6 and 8 t/ha and incorporated down to
20cm depth. Field experiments were laid using Randomized Complete Block Design
(RCBD) with four replications while pot experiment was laid using Complete
Randomized Design (CRD) with three replications. Dry matter yields (DM) yields, P
uptake, P concentrations, extractable P and grain yields were used to assess the
effects of these treatments. The results showed that continued incorporation of OM
banded together with MPR significantly (P=0.05) improved MPR dissolution, P
availability, and increased grain yields. This was supported by highest maize grain
yield (3.01 t/ha) obtained from these continued observations, which was higher than the maximum (2.27 t/ha) obtained in the previous study from the MPR + OM
incorporated down to 20 cm depth. The results of the new experiment showed that
banding of MPR together with OM at the rates of 2, 4 6 and 8 t/ha significantly
(P=0.05) increased MPR dissolution, P availability, and maize grain/ dry matter
yields. The increase was in proportion to the increased rates of OM. For example, in
the pot experiment, MPR + OM increased DM yields from 14.14 to 76.17 g/pot and
4.10 to 70.87 g/pot in Magadu and Sasanda soils, respectively. In the field
experiment, MPR + OM at 2, 4 and 6 t/ha increased extractable P in the soil from
0.18 to 0.47 mg/kg and maize grain yields from 0.36 to 3.38 t/ha. The increase was
also proportional to the increased rates of OM. The highest extractable P (0.47
mg/kg) and grain yields (3.38 t/ha) were observed from MPR + 6 ton OM/ha.Minjingu rock phosphate utilization project-DANID
Effect of phosphate rock placement methods and incorporation of organic residues on phosphorus availability and maize yields in two soils with different phosphorus fixing capacities
No full textDissertationA study was conducted under pot and field conditions to evaluate the effects of
Minjingu phosphate rock (MPR) placement methods and organic residues on MPR
dissolution, P availability and maize yields in two soils with different P fixing
capacities. Observations from two field experiments, one at Sasanda, Mbeya and
another at Magadu, Morogoro were continued to evaluate the effect of continued
addition of organic materials (OM) banded with MPR on MPR dissolution, P
availability and maize yields. One field experiment was carried out at Sasanda to
evaluate the effects of different rates of OM applied together with MPR on MPR
dissolution, P availability and maize yields. For the continued experiments, the
treatments tested were control, broadcasted MPR, 2 to 5 cm width strip banded MPR,
20-cm wide MPR band incorporated to 10 or 20 cm depth, and 20-cm MPR band +
O.M incorporated down to 10 or 20 cm depth. These were tested only in the field.
For the new experiment the treatments tested were control, broadcasted MPR, 2 to 5
cm width strip banded MPR, 20-cm wide MPR band incorporated to 20 cm, and 20-
cm band MPR + OM applied together at 2, 4, 6 and 8 t/ha and incorporated down to
20cm depth. Field experiments were laid using Randomized Complete Block Design
(RCBD) with four replications while pot experiment was laid using Complete
Randomized Design (CRD) with three replications. Dry matter yields (DM) yields, P
uptake, P concentrations, extractable P and grain yields were used to assess the
effects of these treatments. The results showed that continued incorporation of OM
banded together with MPR significantly (P=0.05) improved MPR dissolution, P
availability, and increased grain yields. This was supported by highest maize grain
yield (3.01 t/ha) obtained from these continued observations, which was higher than the maximum (2.27 t/ha) obtained in the previous study from the MPR + OM
incorporated down to 20 cm depth. The results of the new experiment showed that
banding of MPR together with OM at the rates of 2, 4 6 and 8 t/ha significantly
(P=0.05) increased MPR dissolution, P availability, and maize grain/ dry matter
yields. The increase was in proportion to the increased rates of OM. For example, in
the pot experiment, MPR + OM increased DM yields from 14.14 to 76.17 g/pot and
4.10 to 70.87 g/pot in Magadu and Sasanda soils, respectively. In the field
experiment, MPR + OM at 2, 4 and 6 t/ha increased extractable P in the soil from
0.18 to 0.47 mg/kg and maize grain yields from 0.36 to 3.38 t/ha. The increase was
also proportional to the increased rates of OM. The highest extractable P (0.47
mg/kg) and grain yields (3.38 t/ha) were observed from MPR + 6 ton OM/ha.Minjingu rock phosphate utilization project-DANID
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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