Browsing by Author "Semoka, J. M. R."

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Assessment of soil fertility status for Bambara Groundnut Production in South-eastern Tanzania
(IJPSS, 2018-09-13) Tenga, J. J.; Semoka, J. M. R.; Msanya, B. M.
Intensive farming practised in the agro-ecological zones of Makonde plateau (C2) and Inland plain (E5) of south-eastern Tanzania without proper soil management has led to nutrient depletion. The objective of the study was to assess the fertility status of soils in Bambara groundnut growing areas of south-eastern Tanzania. Twenty-two farmers' field sites were sampled and composite samples of top soil at 0 – 20 cm depth were collected for physical and chemical analysis. The results indicate that the soils in the study area are sandy loam (64%), loamy sand (27%) and sandy clay loam (9%). About 28% of the soils in the study area had very low CEC values (< 6 cmol (+) kg soil). Soil pH was strongly acidic to moderately acidic (≤ 5.5) and slightly acidic (≥ 6.0) in the C2 and E5 agro- ecological zones, respectively. Total N was very low (< 0.1%) and organic carbon was very low to low (< 0.6%). Low levels of available P (<10 mg/kg), inadequate S (SO 4 -S) levels (< 10 mg/kg) were observed. The exchangeable K in the C2 zone was very low to low (< 0.05 cmol(+)/kg) while E5 zone had medium K level. The calcium level of C2 was low to medium (0.2 – 2.5 cmol(+)/kg) 2+ whereas that of E5 was medium to high (0.6 – 5.0 cmol(+)/kg). The exchangeable Mg levels were + very low to low (< 0.2 cmol(+)/kg) while Na was < 0.30 cmol(+)/kg soil indicating no sodicity problem. For > 90% of the studied soils extractable Zn was below critical level of 0.6 mg/kg. All soils had adequate extractable Fe whereas > 70% of the soils had high (> 5 mg/kg) extractable Mn. The study area generally indicated low fertility status in terms of N, P, K, S, Mg and Zn, calling for proper management for improving crop production.
Effects of nitrogen fertilizer rates and soybean residue management on nitrate nitrogen in sorghum-soybean intercropping system
(SCIENCEDOMAIN international, 2014-10-11) Kebeney, S. J.; Semoka, J. M. R.; Msanya, B. M.; Ng’etich, W. K.; Chemei, D. K.
An experiment was carried out in Busia County, Kenya at Emalomba (N 00°25′28.8″ E 034°15′ 51.9″), Nambale District to assess the effects of nitrogen fertilizer rates and legume management options on nitrate nitrogen (NO3-N) under intercropping system. Six soybean residue management options were considered: Sole sorghum, sorghum + soybean left to maturity, sorghum + soybean mulched, sorghum + soybean incorporated, sorghum + soybean exsitu and sorghum + soybean exsitu and plot tilled. Three levels of nitrogen (0kg N ha-1, 40kg N ha-1, and 80kg N ha-1 as urea were applied as top-dress and treatments arranged in randomized complete block design. Soil NO3-N was significantly high (P<0.0010) in topsoil with a notable leaching to subsoil due to precipitation. Control treatments had low soil NO3-N in comparison to other treatments implying that, use of inorganic fertilizers to supplement soil N is important. Fertilizer application at 40kg N ha- 1 with respect to on-farm soybean residue management was in relation to NO3-N supply was in the order: sorghum + soybean left to maturity > sorghum + soybean mulched = sorghum + soybean incorporated. Experimental plots with legume residues removed had significantly (P<0.001) low NO3-N. High leaf NO3-N observed points to transfer of N to sorghum by nitrogen fixation signifying importance of intercropping. There was no significant difference between nitrogen fertilizers applied at 40kg N ha-1 and 80kg N ha-1 irrespective of field managed legume residues. Sorghum intercropped with soybean left to maturity with nitrogen fertilizer applied at 40 kg N ha-1 reflected high (P< 0.001) soil NO3-N in comparison to the other management options. It is therefore recommended as a possible optimum rate and legume residue management option to improve soil NO3-N among small scale households with stretched socio-economic ability in Busia County.
Extent of seawater intrusion from Chwaka and Uzi bays into Jozani Groundwater Forest, Zanzibar, Tanzania.
(International Journal of Scientific & Engineering Research,, 2017) Said, M. S.; Maliondo, S. M.S.; Semoka, J. M. R.; Msanya, B. M.
The rise in the total dissolved solids (TDS) in a coastal land is among the signs of seawater intrusion into the land. In many cases, the magnitude of the effects of seawater intrusion depends upon the proximity of the land to the coast, amount, and patterns of freshwater recharging the aquifer underneath. The intention of this study was to determine the extent to which Jozani groundwater forest (JGWF) has been affected by seawater intrusion from Chwaka and Uzi bays. Rainfall data were collected from Tanzania Meteorological Agency (TMA). Spatial and temporal TDS values were collected from temporary wells (TWs) and local wells. Desk work divided JGWF length into 11 northern and 4 eastern gridlines. Along northern gridlines, three grid points were selected on which TWs were drilled for data collection. GARMIN etrex 10 GPS was used for geo-referencing the wells. Water samples were collected at about 0.1 m depth from water surface and were tested in situ using Hanna Combo HI 98129 tester. Water tests were done in the middle of Kiangazi, Masika, Kipupwe and Vuli seasons. The area of JGWF was estimated based on JGWF elevation map. The results showed that the average TDS values in JGWF ranged from 0.4 - 25 x 103 mg L-1. The least TDS values were recorded from the inner parts of JGWF while highest TDS values were recorded from the outmost parts. It was found that rainfall patterns: rainy and dry seasons affected TDS values and their spatial trends. The TDS severity in JGWF area was assigned five categories namely none: least-, slightly-, moderately- and severely-affected areas. The range of TDS values for these categories were 0 – 0.5, 0.5 – 2, 2 - 5, 5 - 10 and >10 x 103 mg L-1 and the areas of occupation were about 342.3 ha (58.2%), 61.8 ha (10.5%), 46.8 ha (8.0%), 47.4 ha (8.1%) and 89.4 ha (15.2%), respectively. In conclusion, it was found that about 77% of JGWF is free from intrusion effects, but there were some variations of TDS values between dry and rainy seasons that also in the long run cause TDS fluctuation between years
Influence of soybean residue management on nitrate nitrogen accumulation and subsequent sorghum yield in Kanhaplic Haplustults of Western Kenya
(Journal of Agriculture and Ecology Research International, 2017) Kebeney, S. J.; Semoka, J. M. R.; Msanya, B. M.; Ng’etich, W. K.
Crop residues are overlooked when making fertilizer recommendations, yet have potential to contribute to soil nitrogen in addition to mineral fertilizer use. A study was carried out in western Kenya to establish the contribution of soybean residues under varied management options and nitrogen fertilizer rates on nitrogen supply to subsequent sorghum crop. Six soybean residue management options were evaluated; sole sorghum, sorghum + soybean left to maturity, sorghum + soybean mulched, sorghum + soybean incorporated, sorghum + soybean exsitu and sorghum + soybean exsitu and plot tilled. Three levels of nitrogen (0 kg N ha -1 , 40 kg N ha -1 , and 80 kg N ha -1 ) as urea were applied as top-dress and treatments arranged in randomized complete block design. -1 Soybean left to maturity at 40 kg N ha indicated significant (P < 0.001) increase (56%) in soil NO 3 -N. Removal of soybean residues resulted in significantly (P < 0.001) lower soil NO 3 -N increase while control treatment and sole sorghum indicated the lowest soil NO 3 -N accumulation irrespective of nitrogen fertilizer rates. Soybean left to maturity indicated significant (P < 0.001) increase (43%) -1 in leaf NO 3 -N accumulation at 40 kg N ha while treatments with soybean residues mulched showed 39% increase and those with residues incorporated, 25% increase. Soybean residues ex- situ and ex-situ and till indicated a decrease (-6% and -7%) in leaf NO 3 -N accumulation, respectively. Sole sorghum had a uniform NO 3 -N increase of 4% irrespective of nitrogen fertilizer rates. It was observed that insitu soybean residues and nitrogen fertilizer application had no significant (P < 0.05) influence on sorghum yield. In conclusion, soil and leaf NO 3 -N accumulation by soybean residues in addition to nitrogen fertilizer does not translate to optimum nor potential research sorghum yields. There is need to research on sulphur and nitrogen to establish their interactive effects on sorghum yields.
Pedological characterization of some typical soils of Busia county, Western Kenya: soil morphology, physico-chemical properties, classification and fertility trends
(International Journal of Plant & Soil Science, 2014-09-06) Kebeney, S. J.; Msanya, B. M.; Ng’etich, W. K.; Semoka, J. M. R.; Serrem, C. K.
Standard soil survey was carried out in Western Kenya to establish representative research sites on the basis of landforms and other physiographic attributes. Soil profiles were characterized at Emalomba (Nambale District) designated (EMA-P1) and at Bukhalalire (Butula District) named BUMA-P1. Both pedons formed from in-situ weathering of granitic rocks under ustic moisture and iso-hyperthermic temperature regimes. Fourteen soil samples from genetic horizons were analyzed for physico-chemical properties. Both pedons had dark brown sandy clay and sandy clay loam topsoils overlying dominantly clayey subsoils. Both pedons indicate clay eluviation-illuviation as a dominant pedogenic process with strong acidic soil conditions and available phosphorus of < 7 mg/kg soil. Organic carbon (OC) is high in EMA-P1 and medium to very low in BUMA-P1 while total nitrogen is medium and low to very low. EMA-P1 and BUMA-P1 have C/N ratios of 8.6 - 9.6 and 12.9 - 24.8 respectively. Both pedons have low to very low exchangeable bases with cation exchange capacity (CEC) < 16 cmol(+)/kg soil. CEC clay values in both pedons are < 24 cmol(+)/kg with BUMA-P1 having < 10 cmol(+)/kg. Both soils are highly weathered with BUMA-P1 depicting more advanced stage of weathering. In the USDA Soil Taxonomy, EMA-P1 was classified as Kanhaplic Haplustults and BUMA-P1 as Typic Kandiustults, both corresponding to Haplic Cutanic Acrisols in WRB. As regards soil fertility trends, OC showed positive correlation with calcium and magnesium indicating organic matter as the main source of plant nutrients. The two pedons differed noticeably in terms of physico-chemical characteristics emphasizing the need to characterize soils before fertilizer recommendations are made. Organic fertilizers are recommended to increase organic matter content and intercropping of cereals with nitrogen fixing legumes to enhance nitrogen in the soils. Use of non-acidifying inorganic fertilizers and lime as soil amendments should also be considered to correct acidity.
Socioeconomic factors and soil fertility management practices affecting sorghum production in Western Kenya: a case study of Busia county
(American Journal of Experimental Agriculture, 2014-09-06) Kebeney, S. J.; Msanya, B. M.; Semoka, J. M. R.; Ng’etich, W. K.; Kipkoech, A. K.
Sorghum (Sorghum bicolor L. Moench), though ranked as the third most important staple food crop in Kenya, farmers still experience periodic crop failure and this is a threat to food and income security. This paper attempts to find the underlying factors responsible for low production and establish farmers’ perceptions on soil fertility management. A cross-sectional study was carried out in Busia County, to relate socioeconomic factors and soil fertility management aspects affecting sorghum yields. Structured interviews and observations were used for data collection, considering the variables: demographic factors, income, farmers’ perception on soil fertility replenishing options, access to agricultural advisory services and yields of sorghum. Results indicate that women are predominant (57.3%) sorghum producing farmers in the County. Literacy level reveals majority of the farmers (49.3%) have primary education as optimum suggesting sorghum production to be through hands-on experience. Individual land ownership was the norm with most farms being 1.5 to 2.0 hectares. Income among respondents is below USD 1.25 per day. Sorghum is ranked very important (56.7%) and is a resource against food shortage. Many farmers (41.3.0%) use traditional seed from previous harvests with 24.0% purchasing seed from agro-dealers or being provided by non-Governmental organizations/projects. Intercropping is associated with food security, improved yields and land inadequacy and not to soil fertility restoration. Inadequate knowledge on the role of legumes and crop residue recycling in soil fertility improvement exists and 38.7% of farmers have access to agricultural information. Gender, social norms, literacy, fertilizer use, accessibility to advisory services and farmers’ perception on soil fertility management options are concluded to impact on sorghum production in Busia County. The existing database on the alternative researched options to restore soil fertility and increase crop yields could be channeled through demonstration plots to farmers in a participatory manner in order to facilitate adoption.
Sulphur and zinc fertilization effects on growth and yield response of rice
(International Journal of Plant & Soil Science, 2016-06-03) Kalala, A. M; Amuri, N. A.; Semoka, J. M. R.
Information on critical concentration and optimum rates of fertilizers is very important in the correction of sulphur (S) and zinc (Zn) deficiencies. A study was carried in the screen house experiments to establish optimum rates and critical concentrations of sulphur and zinc in both soil and rice shoots using soils of Kilombero district, Tanzania. Two experiments were conducted, one with varied levels of S and the other with varied levels of Zn. The treatments were absolute control for both experiments, three levels of S namely 0, 20 and 40 mg kg -1 soil and three levels of Zn -1 namely 0, 5 and 10 mg kg soil. Rice (variety SARO-5) was grown in pots arranged in a randomized complete block design with three replications. The results indicated that soil critical concentration of S was 10.0 mg kg -1 and the S critical range in rice shoots was 0.18 to 0.25%. -1 Established critical level of soil Zn was 1.4 mg kg while the Zn shoots critical concentration was 22 -1 mg kg . Grain yield was significantly increased for plants grown in eight and three out of ten soils -1 tested due to an application of S and Zn, respectively. Rates of 20 mg S and 5 mg Zn kg soil were optimum rates for soils with low S and Zn, respectively. The results indicated that 17 and 6 out of 19 studied soils of Kilombero had S and Zn concentration below the critical level, respectively. It was concluded that sulphur deficiency was widely spread and its application and management is crucial, while Zn deficiency was an emerging problem in the paddy soils of Kilombero valley.