Browsing by Author "Merumba, Mgeta Steven"

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Effect of tillage methods, farmyard manure and potassium rates on some soil chemical properties and nutrient contents in cassava in Kagera, Tanzania
(Journal of Agriculture and Ecology Research International, 2023) Merumba, Mgeta Steven; Semoka, Johnson Mashambo; Semu, Ernest; Msanya, Balthazar Michael; Kibura, Jojianas Kokulamka
A study was conducted in Bukoba, Missenyi and Biharamulo districts, Tanzania for the objective of determining the effect of tillage methods, farmyard manure (FYM) and potassium rates on soil pH and the concentrations of N, P and K in the soils and cassava leaves. The treatments were arranged in the Randomized Complete Block Design (RCBD) using the split-plot design with three replications. Tillage methods (flat tillage, open ridging and tied ridging), were the main plots, and the fertilizer rates [farmyard manure (FYM) alone at 4 MT ha-1 alone 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] and the control, were the sub-plots. The inherent and post-harvest composite soil samples for determining soil pH and the concentration of N, P and K in each site were collected, processed and analysed. Post-harvest soil samples and cassava leaf samples were collected from the control plots and plots that received the combination of FYM at 8 MT ha-1 and potassium at 40 or 120 kg K ha-1 during the second cropping season. The leaf samples were oven dried at 70oC, grounded to pass through 0.5 mm sieve and analyzed. The results indicate that there was no a significant (P = .05) difference in the soil pH and the concentrations of N, P and K in the soils and cassava leaves among the tillage methods. There was a significant (P < .001) difference in the soil pH and the concentrations of N, P and K in the soils and cassava leaves between the control and the combined use of FYM and potassium rates. However, there was no a significant (P =.05) difference in the concentrations of N, P and K in the soils among the combined use of FYM and potassium rates, but there was a significant (P < .001) difference in the concentrations of N and K in cassava leaves among the combined use of FYM and potassium rates. The combined use of FYM at 8 MT ha-1 and potassium at 40 kg K ha-1, and the combined use of FYM at 8 MT ha-1 and potassium at 120 kg K ha-1 significantly (P < .01) increased the soil pH and the concentration of N and K in the soil. However, the combined use of farmyard manure at 8 MT ha-1 and potassium at 120 kg K ha-1 gave significantly (P < .001) higher concentrations of N and K in cassava leaves than the combined use of farmyard manure at 8 MT ha-1 and potassium at 40 kg K ha-1. Therefore, 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, the combined use of farmyard manure at 8 MT ha-1 and potassium at 40 kg K ha-1 could be used.
Effect of tillage, farmyard manure and potassium rates on the perfomance and profitability of cassava in selected districts of Kagera, Tanzania
(Sokoine University of Agriculture, 2022) Merumba, Mgeta Steven
In 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.
Pedological characterization and suitability assessment for cassava production in Bukoba, Missenyi and Biharamulo Districts, Tanzania
(Science Publishing Group, 2020) Merumba, Mgeta Steven; Msanya, Balthazar Michael; Semu, Ernest; Semoka, Johnson Mashambo
A study was conducted in Bukoba, Missenyi and Biharamulo Districts, Tanzania with the objectives of characterizing, classifying and assessing the suitability of the study area for cassava production. A reconnaissance field survey using transect walks and auger observations was done in the study sites, which were geo-referenced in terms of international coordinates using Global Positioning System. Soil profiles representative of the study sites were excavated and named as MARU-P1, MISSE-P1 and BIHA-P1 for Bukoba, Missenyi and Biharamulo Districts, respectively. Soil profile description and data on the morphological features of the representative soils were collected according to the FAO Guidelines for Soil Description. Disturbed and undisturbed soil samples were collected from genetic soil horizons, processed and analyzed in a soil laboratory. Data on site characteristics, climate, soil morphological features and soil physical and chemical properties were used to classify the soils 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 reveal that Pedons MARU-P1 and BIHA-P1 have similar morphological properties, which are different from pedon MISSE-P1. However, the studied pedons differ in their physical and chemical properties, implying differences in their use and management. The climate of the study sites is semi-humid with Udic soil moisture regime, which is generally favourable for crop production. According to the USDA Soil Taxonomy, pedons MARU- P1 and BIHA-P1 were classified as “Typic Kandiudults”. In addition, according to FAO World Reference Base for Soil Resources, pedons MARU-P1 and BIHA-P1 were classified as “Haplic Ferralic Acrisols” and “Chromic Ferralic Acrisols”, respectively. Pedon MISSE-P1 was classified as “Typic Endoaquolls” according to USDA Soil Taxonomy and as “Fluvic Gleyic Phaeozems” according to FAO World Reference Base for Soil Resources. Pedons MISSE-P1 and BIHA-P1 were both evaluated as marginally suitable while MARU-P1 pedon was evaluated as moderately suitable for cassava production due to soil fertility constraints. We recommended specific soil fertility management strategies in each studied site for optimum cassava yields.
Profitability of using different rates of farmyard manure and potassium fertilizer for cassava production in Bukoba, Missenyi and Biharamulo districts, Tanzania
(ResearchGate, 2022-08-10) Merumba, Mgeta Steven; Semu, Ernest; Semoka, Johnson Mashambo; Msanya, Balthazar Michael; Kibura, Jojianas Kokulamka; Blandes, Joyce Siima
The resolution of using or not using a particular technology in crop production is governed by the profitability of that technology being used. A study was conducted in Bukoba, Missenyi and Biharamulo districts in the Kagera region during the 2018/19 and 2019/20 cropping seasons to determine the economic benefit of using different rates of farmyard manure (FYM) and potassium (K) fertilizer in cassava production. One village potential for cassava production was selected in each district for establishment of cassava trials. Three tillage methods [flat tillage, tied ridging and -1 -1 open ridging] and eleven fertilizer rates [FYM at 4 or 8 MT ha , N40P30 + K at 40, 80 or 120 kg ha , FYM at 4 or 8 MT ha-1 + K at 40, 80 or 120 kg ha-1] and the control, were arranged in a Randomized Complete Block Design (RCBD) with three replications using a split-plot design. Tillage methods were the main plots and fertilizer rates were the subplots. Cassava yields (MT ha-1) were collected at harvesting (12 months after planting). Partial budget analysis was carried out to estimate the gross values using the adjusted yields at market price for cassava and fertilizers. Costs and benefits -1 -1 were calculated on a hectare basis, in Tanzania Shillings (TShs) ha , and converted to USD ha based on the prevailing exchange rate of 1 USD, equivalent to 2 300 TShs. All variable costs were summed up to total variable cost (TVC). The net benefits (NB) [gross benefit (GB) - TVC] ha-1 of the tested treatments were calculated and used to assess the profitability of each treatment. Moreover, the benefit-cost ratios (BCR) [net benefit ÷ TVC] of the tested treatments were compared to the acceptable value of greater than 2 for the technology to be adopted by farmers. The results indicated that in both cropping seasons, and in all studied sites, all the tested fertilizer types and rates gave acceptable BCR of greater than 2, implying that all the fertilizer types and rates could be used for cassava production in the study area. The results on net benefit indicated that the combined use of FYM at 8 MT ha-1 and potassium fertilizer at 80 kg K ha-1 gave higher net benefit (3 020 500 – 9 168 000 TShs ha-1 (1 313.3 – 3 986.1 USD ha-1) than the other fertilizer types and rates (1 915 000 – 9 024 500 (832.6 – 3 923.7 USD ha-1) and is therefore, desirable for increasing cassava root yield and net benefit. However, for the resource-poor farmers, the combined use of farmyard manure at 8 MT ha-1 and potassium fertilizer at 40 kg K ha-1 can still be adopted because, for some reason, not all the famers can afford the best treatment.
Soil fertility status in Bukoba, Missenyi and Biharamulo Districts in Kagera Region, Tanzania
(Science Publishing Group, 2020) Merumba, Mgeta Steven; Semu, Ernest; Semoka, Johnson Mashambo; Msanya, Balthazar Michael
The study was conducted in three Districts of Kagera Region, Tanzania to assess the inherent soil fertility status of farmers' fields. Thirty-three fields, located three to five km apart, were selected and soil samples (0 – 20 cm depth) were taken, mixed thoroughly, air-dried, ground, sieved through 2 mm sieve, and analyzed in the soil laboratory based on standard laboratory analytical procedures. Correlation analyses among soil chemical properties were performed using IBM SPSS Statistic 20 and the mean values were calculated using Excel spreadsheet statistical package. Soil fertility index (SFI) and limiting nutrients were used to assess the fertility status of the fields. The results indicated that soil textures ranged from sandy clay loam to sandy clay, clay loam, clay to sandy. Soil pH ranged from strongly acid (5.1) to slightly acid (6.1) while EC levels were very low (0.03 - 0.17 dS m-1). Total TN ranged from very low to medium (0.04 - 0.41%), extractable P ranged from low to high (0.44 - 86.44 mg kg-1) and Exchangeable K ranged from very low to medium (0.08 - 0.98 cmol(+) kg-1). Exchangeable S ranged from low to medium (2.27 - 12.14 mg kg-1) while CEC ranged from very low to medium (5.20 - 23.00 cmol(+) kg-1), extractable Zn ranged from medium to high (0.85 - 18.41 mg kg-1), Cu from medium to high (0.47 - 2.81 mg kg-1), and Mn and Fe were medium (2.24 - 70.34 mg kg-1) and high (37.50 - 473.21 mg kg-1), respectively. The results also indicated both positive (r=+ve) and negative (r=-ve) and both significantly (p≤0.05) and highly significantly (p≤0.01) correlations among the soil chemical properties in each districts. Based on SFI, the soil fertility status of the studied fields ranged from poor fertility to good fertility. The results on the limiting nutrients across the studied fields indicated that N and K were the most limiting nutrients (67%) followed by P (52%), S (32%), Mg and OC (18%) and the least was Ca (15%). The results also indicated that N and P were the most limiting nutrients in Bukoba District while N and S were the most limiting nutrients in Missenyi District and N, P and K were the most limiting nutrients in Biharamulo District. Therefore, specific soil fertility management practices are recommended based on limiting nutrients in those fields having inadequate levels of plant nutrients together with training of farmers on proper use of the appropriate soil fertility management practices.