Department of Soil and Geological Sciences

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Agronomic evaluation of some industrial wastes as alternative sources of plant nutrients in Morogoro District, Tanzania
(Sokoine University of Agriculture, 2001) Ndaki, Stephen Mhoja Mashauri
A study’ was conducted at Magadu. Morogoro. Tanzania to evaluate the industrial wastes as alternative sources of plant nutrients and/or soil conditioners. The soil of Magadu was classified by Kaaya (1989) as Oxic Haplustult. The soil was characterised in this study for its physical and chemical properties prior to planting of the test crop. The analytical data showed that the soil was strongly acidic with a pH of 5.1. Total N. available P. %OC, exchangeable Ca and Na. CEC. and DTPA extractable Zn were in the low range. Exchangeable Mg was in the medium range, while exchangeable K. DTPA extractable Fe, Mn and Cu were high. In the field a randomised complete block design was used to evaluate the wastes using maize as test crop. The rate of waste application were 5.24 4.8, 4.25, 4.5 and 3.7 tonnes/ha of waste tea, wattle bark chippings, waste tobacco, wood ash and saw dust respectively. Prior to soil incorporation, the wastes were analysed for their chemical properties. Maize dry matter yields were significantly higher in plots which received 5.24 tonnes/ha of waste tea followed by plots which received 4.25 and 4.5 tonnes/ha of waste tobacco and wood ash respectively. Maize grain yields were significantly higher in waste tea and wattle bark chippings amended plots than in the other waste amended plots. At the end of the growing season the soil was analysed to evaluate the residual effect of wastes on soil properties. Soil pH, available water capacity, available P, % OC, total N, exchangeable bases, CEC, DTPA extractable Zn and Cu in waste amended plots increased in the top 15 cm of soil relative to the control plots. DTPA extractable Fe and Mn, exchangeable Al and acidity were significantly reduced in all waste treatments. Total N and % OC in wood ash and saw dust amended plots were at par with those found in control plots. The results from the field suggested that when applied at agronomic rates, industrial wastes can produce satisfactory plant growth and yields. The results revealed further that waste application on a long term basis will allow good build up of soil organic matter and plant nutrients which in turn will improve on soil productivity. It is recommended that N supplement to wood ash which is rich in almost all macro and micronutrients (except N) would balance its nutrient supply to plants. A glasshouse decomposition experiment was carried out with some wastes including sawdust and wattle bark chippings in perforated plastic litter bags. The wastes were either surface applied or buried to 10 cm depth in wooden troughs. The decomposition process which was monitored at 0. 3, 6, 9, and 12 weeks of incubation revealed that soil incorporated wastes decomposed and released nutrients faster than surface applied ones.
Agronomic management strategies for adaptation to the current climate variability: the case of North-Eastern Tanzania
(2014) Tumbo, Siza D.; Rwehumbiza, Filbert B.; Kahimba, Frederick C.; Enfors, Elin; Mahoo, Henry F.; Mbilinyi, Boniface P.; Mkoga, Zacharia; Churi, Ayubu
Rainfed agriculture in semi-arid areas of sub-Saharan Africa faces a great challenge due to increasingly high variability and unreliability of rainfall. Two of the effective adaptive responses to reduce the vulnerability to the changing climate are through use of soil and water conservation technologies and employment of improved agronomic practices. A study was conducted to quantify the risk and profitability of agronomic management strategies for maize using long-term climatic data and a crop simulation model. APSIM model was used to perform long-term simulations of different management strategies. Simulated maize grain yield for different cultivars and sets of management strategies were evaluated to establish the associated risks and benefits. Results indicate that planting Situka or SC401 during Masika season instead of Kito or other cultivars, gives a yield of more than 1 ton/ha under conventional methods. Maize yield increases to 2t/ha or even higher with the use of fertilizers and recommended management practices. The cost benefit analysis indicated that income greater than USD 700 per ha could be obtained when recommended practices are applied, with Situka and SC401 as the maize varieties planted. Based on the results of the study, it is recommended that farmers should employ improved agronomic management practices only when the seasonal forecast indicates above normal rainfall. The early availability of seasonal rainfall forecast is thus vital. Alternatively, farmers are much safer if they continue to employ their conventional approaches of farming because these have lower risks.
Anthropogenic soils and land use patterns in relation to small mammal and flea abundance in plague endemic area of Western Usambara Mountains, Tanzania
(Tanzania Journal of Health Research, 2014-07) Kimaro, D. N.; Msanya, B. M.; Meliyo, J.; Hieronimo, Proches; Mwango, Sibaway; Kihupi, N. I.; Gulinck, Hubert; Deckers, Jozef, A.
Heterogeneity in the landscapes of West Usambara Mountains on land use and human activities has been reported. However, the interface of land use patterns and human modified soils with small mammal and flea abundance for possible explanation of plague has not been explored. This study was carried out to determine the link between anthropogenic soils and land use patterns on small mammal and flea abundance and the occurrence of reported plague in the Western Usambara Mountains in Tanzania. Standard soil survey methods were used to identify and describe soils and land use patterns on lower slopes and valley bottoms on which the surrounding villages are reported to have high and medium plague frequencies. The identified soils were characterised in terms of their morphological and physico-chemical properties and classified according to FAO-World Reference Base for Soil Resources. Small mammals were trapped on the same landscape positions and identified to genus/species level. Fleas were removed from the trapped small mammals, counted and identified to species level. In total 57 small mammals were captured from which 32 fleas were collected. Results show that human settlements and mixed cultivation on lower slopes and continuous vegetable cropping in the valley bottoms are dominant land use types. Intensive use of forest soils, manuring and irrigation on farms in the studied landscapes have contributed to the development of uniquely human modified soils namely Hortic Anthrosols in the lower slopes and Plaggic Irragric Hortic Anthrosols in valley bottoms. The identified anthropogenic soils and land use patterns are associated with high abundance of small mammals (Mastomys natalensis) and flea species (Xenopsylla brasiliensis and Dinopsyllus lypusus). This phenomenon is vividly apparent in the villages with medium to high plague frequencies. The study suggests that plague surveillance programmes should consider the existing relationship between anthropogenic soils, land use patterns, small mammal and flea abundance.
Assessing drivers of soil properties and classification in the West Usambara mountains, Tanzania
(Elsevier, 2017-10-16) Massawe, B. H. J.; Winowiecki, L.; Meliyo, J. L.; Mbogoni, J. D. J.; Msanya, B. M.; Kimaro, D.; Deckersf, J.; Gulinck, H.; Lyamchai, C.; Sayula, G.; Msokah, E.; Vagen, T.; Brush, G.; Jelinskii, N. A.
Improved soil information in tropical montane regions is critical for conservation, sustainable agricultural management, and land use planning, but is often challenged by topographic and land-use heterogeneity. The West Usambara mountains are a part of the Eastern Arc chain of mountains of Tanzania and Kenya, a globally important tropical montane ecoregion made up of isolated fault-block mountain complexes characterized by high biological endemism, population density, and agronomic productivity. We synthesized novel and legacy soil data from published and unpublished studies to better understand the drivers of soil property distributions and soil diversity in the West Usambaras, and to serve as a foundation for improved soil mapping efforts across the Eastern Arc. Analysis of the resulting dataset of 468 sites (ranging in elevation from 1040 to 2230 m.a.s.l.) revealed that soil properties varied more significantly by land use and topography than by soil type, suggesting that future mapping efforts in the region should focus primarily on soil property prediction and secondarily on soil classification. Sites under cultivated land uses had the lowest topsoil soil organic carbon (SOC) concentrations and highest pH values, and SOC generally increased with increasing elevation. Valley soils had significantly lower surface SOC concentrations but higher exchangeable bases and pH values than all other landscape positions. Soil pH decreased by an average of 3.5 units across the entire elevation gradient and decreased by 1 unit with elevation even after SOC, land use and landscape position were included in multiple regression models. The relationship of cation exchange capacity (CEC) to SOC and clay content varied by landscape position. Therefore, particularly in montane regions where soils can vary significantly over short distances, multiple functions may be necessary to produce improved estimates of parameters such as CEC. Soil classification was driven most strongly by topography, with Acrisols (WRB Reference Group) and Ultisols (U.S. Soil Taxonomy (ST)) as the dominant soil types, located primarily on mid slope, upper slope and crest landscape positions, making up 47% and 75% of observed profiles, respectively. However, five ST Orders and seven WRB Reference Groups were present in the dataset, with the highest soil diversity occurring at lower slope landscape positions. Conclusions drawn from this large dataset support previous work in the West Usambaras and provide a conceptual foundation from which to build improved soil maps across the Eastern Arc and in other tropical montane systems throughout the world.
Assessment of bat guano as source of nutrients for rice production
(Sokoine University of Agriculture, 2018) Hatibu, A. A.
Rice production in Tanzania is generally low and continuing to decline partly due to low soil fertility. Smallholder farmers are continuing cultivating in the same area with little or without use of fertilizer due to limited access to costly industrial fertilizers. This trend results into continuous mining of plant nutrients such as phosphorous (P) and other essential nutrients elements which are needed by rice for growth and development; and consequently decline in soil fertility and hence rice production. The country has several bat guano deposits, but none of them are adequately exploited as alternative source of plant nutrients and soil amendment to improve the soil properties because of lack of information on their potential suitability. This study, therefore, aimed to evaluate the agronomic potential of selected bat guano for enhancing soil fertility and improving rice production. Selected bat guano in Tanzania were studied in a laboratory incubation experiment for 112 days to assess P release patterns and establish the pick periods of P mineralization in Department of Soil and Geological Sciences (DSGS) laboratory. Guanos used in this study were from Kisarawe cave A (BGK-A), Kisarawe cave B (BGK-B) and Sukumawera cave (BGS) with 8.55, 7.03 and 3.45 % total P, respectively. Guano from each deposit was mixed with soil at varying rates of 0, 10, 20, 40 and 80 mg P 200 g -1 soil. The incubation experiment was arranged as a 3x5 factorial experiment in randomized complete design (RCD) with three replications. In addition to incubation experiment pot experiment was setup to evaluate the response of rice to selected bat guano as a source of phosphorous. The experiment was carried out in a screen house at Sokoine University of Agriculture (SUA). The experiment was a 4 × 6 factorial in a Randomized Complete Block Design (RCBD) replicated three times. The treatments were three bat guano from Kisarawe cave A (BGK-A), cave B (BGK-B), and Sukumawera (BGS) and Triple Super Phosphate (TSP) as standard fertilizer all at six application rates (absolute control, 0, 10, 20, 40 and 80 mg P kg -1 soil). Bat guano was supplemented with urea (CO (NH 2 ) 2 ) which was applied at a rate of 400 mg N kg -1 and zinc sulphate (ZnSO 4 ) was applied at a rate of 2.5 mg Zn kg -1 . Rice SARO variety (TXD 306) was grown as a test crop. From the incubation experiment, results showed gradual increase of extractable/available P from 28 days to 84 days followed by a decrease in P release up to 112 days of incubation. In all days of incubation there was a highly significant interaction effect of P- sources and application rates (P < 0.05) on P released from guano applied at the rate of 80 mg kg -1 . The soil pH showed a very strong negative correlation with phosphorus released (r > 0.8) from the first day to 112 th days of incubation. The pot experiment results indicated that there was a significant (P < 0.05) effect of all three guano and standard P fertilizer (TSP) on dry matter accumulation at maturity in the order TSP > BGK-A > BGS > BGK-B. There was a significantly (P < 0.05) higher effect of P at 80 mg P kg -1 for all P sources on dry matter accumulation at maturity. Interaction effect of P sources and P rates was highly significant (P < 0.05) on dry matter accumulation at maturity. Plant physiological parameters (number of tillers, plant height, panicle height and number of panicles per plant), as well as rice grain yield were also significantly higher for plants receiving 80 mg P kg -1 for all P sources. Positive correlation between grain yield and other yield components was observed indicating better crop response to P sources and P rates applied. Both incubation and pot experiment results indicated guano to have similar effect to TSP in releasing P for rice; hence the potential for application as alterative P source. It was further observed that at application rate of 80 mg P kg -1 of guano, the studied guanos would release adequate phosphorous for plant growth. Because these results were obtained under controlled environment field trials are recommended to evaluate the response of rice and other crops to soil applied guano for meaningful recommendations to farmers.
Assessment of copper and zinc status of some soils of Iringa district
(Sokoine University of Agriculture, 1992) Mkangwa, Chaboba Zaid
The objectives of this study were to select suitable extractants for determining available copper and zinc in soils of Iringa district and to assess the fertility status of the two nutrients in the district. Two sets, each of ten soils for one element, were selected for glasshouse studies using maize as a test crop. The soils were treated with 0 and 5 kg ha' of either copper or zinc in their respective trials. Three extractants, viz: 0.1M EDTA-(NH.)jCO;, 0.005M DTPA and 0.1NHC1 were tested for their suitability to extract these elements. The concentrations of these elements in maize shoots were also determined. A total of 61 samples were collected from the district and analyzed for copper and zinc using the methods found to be suitable. Copper and zinc application slightly increased dry matter in four and eight soils, respectively, out of the ten soils tested. However, the increase was not statistically significant. The 0.1N HC1 extractant was superior to the other two in extracting zinc but none of the methods was suitable for copper. The tentative critical concentration for zinc was found to be 0.28ppm. Application of either of these elements in the soils, significantly increased their concentration in the plants. The tentative critical 6.30ppm. copper concentration in maize shoots was For zinc, the critical concentration in shoots was not determined because all the values obtained were above critical concentration extractant, range reported elsewhere. zinc concentration Using the 0.1N HC1 in the soil ranged from 0.14 to 27.30 ppm. For zinc, two fertility classes: medium and high were obtained. The proportions of soils which fell in the medium and high zinc fertility classes were 8.20 and 51.80%, respectively.
Assessment of in-situ rainwater harvesting techniques for improving smallholder maize production in semi arid areas of Morogoro, Tanzania
(Sokoine University of Agriculture, 2003) Bwana,Thomas Nestory
A study was conducted at Morogoro, Tanzania during long rains ('Masika') to evaluate the effect of in~situ rainwater harvesting (RWH) techniques in improving maize yield. Three commonly used techniques, ridging after planting (RA), ridging before planting (RJB), and tied ridging (TR) were tested against a no tillage practice locally known as "kuberega" (K) on an Oxic Paleustalf soil with maize (Zea maize L.) variety TMV1 as the test crop. Daily rainfall was recorded and the total rainfall received during the 2001/02 growing season was 562 mm with a series of dry spells. Moisture content at 0-15 and 15-30 cm depth was measured twice weekly. Significantly (p<0.05) higher soil moisture variation and lower moisture content were noted in treatment K than in the other treatments. Treatments RB and TR had lower moisture variations and higher moisture content throughout the season. Grain yield, biomass, plant height, bulk density, infiltration rates (on the ridge and in the furrow), runoff and soil loss were also measured. Significant differences were observed among the treatments (p<0.05) in runoff, soil loss, on ridge infiltration, grain yield, and biomass. The maize yield ranged between 2.97 Mg/ha and 3.89 Mg/ha for treatments K and RB, respectively. The runoff loss was highest for K and least for TR. Treatments K and RA did not differ significantly from each other but differed significantly from RB and TR (p<0.05). Soil loss had a similar trend as that of runoff. More runoff loss was recorded early than late in the season. On ridge infiltration was not significantly different for treatments TR, RA, and RB but was significantly higher than the control (K) at (p<0.05). On furrow infiltration, however, had a reverse order with K having higher rates. Bulk density in both depths (0-15 and higher bulk density. The results show that ridges are effective in-situ rainwater harvesting technique that conserves water and soil and improves productivity.However, ridging after planting is inferior to both ridging before planting and tied ridging.15-30 cm) was not statistically different (p<0.05), however treatment K had slightl
Assessment of nitrate levels in water and soils for agriculture and human utilization in Singida district, Tanzania
(Sokoine University of Agriculture, 2016) Lwiza, M. L.
Population growth in urban areas has caused increase in demand of good quality water for domestic use. Due tohigh nitrate levels in water sources reported by District water authoritiesin Singida District, this study was carried to determine sources, levels and distribution of nitrates in water and soils for agriculture and human utilization. Firstly, a reconnaissance survey was carried to identify water sources with high, medium and low levels of nitrates and determine nitrate levels in surrounding soils. Surface water, underground water and surrounding surface soils samples were randomly collected and analysed for nitrate levels.Their results assisted in identifying areas with high, medium and low nitrate levels where detailed soil sampling and analyses for nitrate levels in soils was carried out.Analysis of soils and water resources revealed high levels of nitrates in water samples ranging from 105 to 476mgL-1and25.2 to 114.8mgkg-1in soils.The distribution of soil nitrates along transects indicated that higher levels were recorded at lower slopes whilelower levels were recorded in the upper slopes. The distribution of nitrate with soil depth was quite variable. In some areas the soil nitrate levels increased with increasing soil depth while in other areas nitrate levels decreased with increasing depths.The nitrate levels in water found to beabove the tolerable limits of 20 mgL-1 and 50 mgL-1set by TBS (2005) and WHO (2007),respectively. Nitratelevels in soils are within the tolerable limits forcrop production. Due to observed high nitrate levels in water, more researchis required to generate sufficient data on the suitability of water for human consumption. The study on the dynamics ofnitrate in soils and water is recommended in orderto come up with strategies of reducing nitrate levels in water.
Assessment of nutrient and biomass yield of medium and long duration pigeon pea in a pigeon pea-groundnut intercropping system in Malawi
(Journal of Sustainable Society, 2013) Phiri, Austin Tenthani; Msaky, John J.; Mrema, Jerome; Kanyama-Phiri, George Yobe; Harawa, Rebbie
Preliminary assessment of the performance of the medium and long duration pigeon pea in a pigeon pea- groundnut intercropping system was conducted at Chitedze Agricultural Research Station (S 13 0 59’ 23.2”, E033 0 38’ 36.8”) in the 2011/2012 cropping season. An experiment involving eight treatments replicated three times in a randomized complete block design was established. Two pigeon pea varieties, long (ICEAP 04000) and medium duration (ICEAP 00557) and groundnut (CG 7) were grown as monocultures and intercrops. The intercrops involved planting either of the pigeon pea varieties with groundnut. Baseline soil data indicate that the soil pH was acid to moderately acid both in the top (mean=5.4-5.7) and the sub soil (mean=5.4-5.6) in all the treatment plots, with mostly low to marginally adequate total nitrogen content both in the top (mean=0.08- 0.14%) and the sub soil (mean=0.09-0.13%). The soil organic carbon content was medium in the top soil (mean=0.9-1.6%) as well as sub soil (mean=1.1-1.6%) across the treatment plots. At the same time soil phosphorus was low to marginally adequate in the top soil (mean=16.8-27.6 mg kg -1 ) and marginally adequate in the sub soil (mean=20.8-25.6 mg kg -1 ), suggesting low soil fertility. The assessment of the above ground groundnut biomass indicate a mean yield range of 479-656 kg ha -1 . While the assessment of the total biomass yield of the pigeon pea varieties indicate a mean yield range of 2,034-2,593 kg ha -1 . In terms of estimated nitrogen yields returned to the soil, the medium duration pigeon pea-groundnut intercrop (mean=50.6 kg N ha -1 ) and the long duration pigeon pea-groundnut intercrop (mean=49.6 kg N ha -1 ) gave significantly (p<0.05) higher yields than by the monocultures of long duration pigeon pea (mean=41.1 kg N ha -1 ) and medium duration pigeon pea (mean=41.0 kg N ha -1 ). Statistically (p<0.05), the lowest amount of estimated nitrogen yield was generated by the groundnut sole crop (mean=12.8 kg N ha -1 ). Overall, the intercrops showed yield advantage (total LER >1.0) compared with the monoculture on equal land area. For the Malawian smallholder farmers, this suggests that mineral N supplementation in a legume-cereal rotation system for enhanced crop productivity might be less in the double legume-cereal rotation mode than in a legume monoculture-cereal rotation system.
Assessment of salt-affected soil in selected rice irrigation schemes in Tanzania: understanding salt types for optimizing management approaches
(Frontiers in Soil Science, 2024-04-23) Omar Moh’d, M.; Massawe Boniface, H. J.; Shitindi Mawazo, J.; Pedersen Ole; Meliyo Joel, L .; Fue Kadeghe, G.
Salt-affected soils have serious implications for agricultural land quality and productivity, leading to a reduction in the net cultivable area available for food production. This issue has emerged as one of the foremost global challenges in recent years, impacting both food security and environmental sustainability. This research focuses on soil characterizations conducted in three irrigation schemes to understand the types, distribution, and nature of salt-affected soils. Auger observations served as the basic methodology for soil unit delineation in this study. Twelve representative soil pits with a depth of more than 160 cm were described, and undisturbed and disturbed samples were collected and analyzed for physical and chemical properties. The schemes were characterized by low levels of available phosphorus, organic carbon, and total nitrogen, as well as variations in exchangeable bases. Furthermore, 37.5% of the analyzed horizons highlighted the presence of salt-affected soils. Sodium was the predominant cation, followed by magnesium, potassium, and calcium. Likewise, HCO3− was the dominant anion, followed by Cl− and SO42−. The results of this study reveal the existence of two types of salt-affected soil. Uturo irrigation scheme had sodic soils, while the Ndungu irrigation scheme had saline-sodic soils. Additionally, both sodic and saline-sodic soils have been discovered in the Mawala irrigation scheme. The root cause of this challenge is inherent soil conditions, exacerbated by inadequate drainage infrastructure. Therefore, measures such as the application of gypsum followed by salt leaching, improving soil drainage by incorporating organic matter, improving drainage infrastructure, and using rice-tolerant varieties are recommended to mitigate salt stress and improve soil fertility. It is imperative to establish a robust framework for continuous monitoring and regular assessment of soil health to enable timely interventions and informed decisions for sustainable agricultural management.
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.
Assessment of soil fertility status of three soils after four years of continuous application of different nutrients
(Sokoine University of Agriculture, 2004) Mbanzibwa,Deusdedith
A study was undertaken to assess the fertility status of three soils following four years of continual application of different nutrients. The three soils were from Mlingano, Nkundi and Sasanda, which are classified as Rhodic Kandiustox, Acruoxic Kandiustult and Dystrict Haplustand, respectively. The study was conducted under both field and glasshouse conditions. For the pot experiment conducted at the SUA glasshouse all three soils were used whereas field experiment was conducted only at Nkundi site. Soils for pot experiment were taken from absolute control plots and from plots treated with TSP and MPR at the rate of 120 kg P/ha. Under field study one more treatment, namely control for P was included. The results showed that application of different nutrients, except nitrogen, led to build up in levels of applied nutrients. Application of MPR or TSP increased levels of Bray 1-P from low to medium and high levels, respectively, in Nkundi and Mlingano soils. In Sasanda soil, Bray 1-P remained below 5 mg P/kg despite application of TSP and MPR. This was attributed to high P fixation capacity of Sasanda soil. In Nkundi soil, MPR application raised Bray 1-P from 5.0 mg P/kg to 41.7 mg P/kg whereas in Mlingano soil Bray 1-P was raised from 2.6 mg P/kg to 39.4 mg P/kg. Application of TSP raised Bray 1-P to above 105 mg P/kg in Mlingano and Nkundi soils but only to 4.7 mg P/kg in Sasanda soil. Zinc and copper increased to sufficient levels in all soils due to application of zinc sulphate and copper sulphate fertilizers. Use of TSP or MPR decreased soil pH in Mlingano and Nkundi soils but the decrease was less in soil treated with MPR. For instance in Mlingano soil, pH decreased from 5.5 to 5.4 and 5.0 for soils treated with MPR and TSP, respectively. However in Sasanda soil MPR increased soil pH from 5.0 to 5.3 and there occurred no shift in pH in plots treated with TSP. Residual P increased significantly (P = 0.05) the maize dry matter and grain yields in plots treated with TSP and MPR. The increase in dry matter and grain yields due to residual P from MPR and TSP were comparable. In Mlingano and Nkundi soils, diy matter yields ranged between 7.29 and 64.77 g/pot whereas in Sasanda soil it ranged between 2.12 and 22.10 g/pot. At Nkundi site, residual P from MPR and TSP gave yields of 4.23 and 4.73 t ha'1,respectively. Yield in absolute control and control for P treatments were 1.03 and 1.83 t ha'’, respectively. It was concluded that residual P from MPR and TSP had comparable effects on maize production.
Assessment of soil N, P, and K status of selected paddy growing areas of Tanzania
(2000) Semoka, J.M.R.; Mnguu, Y.O.
Suitable diagnostic criteria to assess the N, P and K status of rice growing areas particularly in developing countries like Tanzania are required. The objective of this study was to develop such criteria in selected rice growing areas of Tanzania and relate nutrient levels to rice response to fertilizer appli cation; Soil samples from 10 paddy growing areas of Tanzania were testedfor N, P and K using selected indices. Nitrogen supply was assessed by organic carbon (OC), total Nand alkaline-KMn04-N while P was assessed by Olsen, Bray-1 and the iron oxide coated-filter paper strip (Pi) methods. Potassium was extracted by neutral 1 N NH40Ac. Extractable nutrients were correlated with DM Yields and nutrient uptakefrom a glasshouse experiment which was also used to assess response of rice to these nutrients. OJ the three Nindices evaluated, only OC correlated significantly (r = 0.73, P< 0.05) with n'ce DMyield thus serving as a good index of N supply. Asfor P indices, Olsen P gave a highly significant correlation with rice DM yield (r = 0.85, P < 0.01) while the relationships with the other two methods gave lower correlation coefficients. All the soils tested were deficient in N and thus no criticallevelfor N could be established while six soils out of 10 were deficient in P. The critical soil P level for Olsen method was estimated to be 20 mg Ikg. The extracted K values were all found to be higher than critical values established elsewhere. Therefore; Nand P are important constraints to rice production in Tanzania and appropriate recommendations should be drawn and demonstrated to farmers.
Assessment of suitability of the soils of madura research institute, Arusha, Tanzania, for the production of soybeans and mungbeans
(Sokoine University of Agriculture, 2001) Mlahagwa, Moses Raphael
A field study was conducted to assess the suitability of the soils of Madiira Research Institute farm for the introduction of growing and production of vegetable soybeans and mungbeans in Tanzania. The specific intention was to assess the fertility status of the soils, determine the plant uptake of the essential nutrient elements from the soils, and try to suggest measures and soil fertility management strategies for the sustainable and optimal production of vegetable soybean and mungbean production. Composite soil samples for the determination of the physical and chemical properties were sampled from two sites selected on the farm. About 400 m2 of land for each site was plowed and then harrowed and each site was divided into three 8 m x 6 m plots/blocks for four soybeans and for five mungbeans, grown at a spacing of 30 cm x 10 cm and replicated three times respectively. Just before flowering nine plants of each line and from each block were harvested for dry matter yield determinations and total plant nutrient analysis. The other plants were left on the field to grow to maturity for grain yield determinations. The soils were found to be medium acidic, with medium CEC, OC, exchangeable Ca, and Mg, low levels of total N, and high levels of exchangeable K and Bray-1 P. The DTPA extractable Fe and Cu were above the critical limit, while Zn and Mn were medium. The plant analysis for soybeans showed that P and Zn correlated positively with the dry matter yields while total N, Ca, Mg, K, Fe, Cu and Mn correlated negatively with the same. Nitrogen, Mg, K, Fe, Cu and Mn correlated positively with grain yields while Ca, Zn and P correlated negatively with the same. The plant analysis for mungbeans showed that N, Mg, K, Zn and Cu correlated positively with dry matter yields while P, Ca, Fe and Mn correlated negatively with the same. Nitrogen, Mg, K, Zn, Cu and Mn correlated positively with grain yields while Ca, Fe and P correlated negatively with the same. The soybean performances based on fresh grain yields were in the following order: GC 84051-32-1 AGS 338 > AGS 329 > AGS 292 corresponding to 14730.0, 8861.6, 6447.0, and 6364.3 kg/ha respectively, while mungbean performances were: VC 6173(b-10) VC 6148(50-12) > VC 6372(45-8) > VC 6379(232-1) > KANTI corresponding to 11178.0, 10549.3, 9167.6, 8547.0 and 6553.3 kg/ha respectively. The soils analytical data indicate that the soils are of medium fertility status, that is medium levels of CEC (16.2-16.8 cmol (+)/kg soil), OC (1.3-1.5%), Ca (8.0-8.1 cmol (+)/kg soil), Mg (2.7-3.0 cmol (+)/kg soil) and low levels of total N (0.190.22%), hence can support the growth of soybeans and mungbeans in the short-term period. Recommendations are made to publicise the production of the best two high yielding soybean lines (i.e. GC 84051-32-1 and AGS 338) and mungbean lines (i.e. VC 6173(b-10) and VC 6148(50-12). Seed inoculation for effective Ni-fixation is recommended. On-site incorporation of the legume vegetable crop residues into the soils and further experiments and use of fertilizer rates are recommended for the sustainable soybean and mungbean production.
Assessment of the fertility status of soils of rice growing areas of Same District, Kilimanjaro Region, Tanzania.
(Sokoine University of Agriculture, 2003) Amur, Nyambilila
This study was conducted to assess the fertility status of the soils of rice growing areas of Same district. Thirty soil samples were collected from ten different sites where rice is grown. Following laboratory analysis, three bulk soil samples were collected from Kisiwani, Ndungu and Kihurio for pot experiments. The laboratory analysis included determination of total N, organic carbon, P by Bray 1 and Olsen methods, and exchangeable bases by ammonium acetate saturation. The micronutrients were determined by extracting with 0.005M DTPA at pH 7.3. The response of rice (Oryza saliva L) variety super SSD5 to N, P and K, as well as to different levels of Zn were assessed in a glasshouse experiment where plants were grown for 56 days. The harvested plant samples were analysed for N, P, K, Ca, Mg, Zn and Fe using the HNO3-H2O2 wet digestion procedure. The results showed that all the soils in this study were deficient in N. About 53% of the soils had low available P. All the soils had adequate levels of K, Ca, Mg and Na, with the exception of soils from Ndungu, which had a low K, supply. Also, most of the soils had low Zn levels, and only two sites had adequate Zn levels. Soils from Mbugani had low Fe while the rest had adequate Fe and Cu. The glasshouse experiments showed that application of N, P and K increased rice dry matter yields in all the soils used. It was further revealed that Zn supplementation in addition to NPK also increased rice dry matter yields further. The results also indicated that the uptake of each nutrient applied was consistent with the dry matter yields increases. It was concluded that most of the soils under rice cropping in the district were deficient in N, P and Zn and required fertilisation using these nutrients. Iron was also required in Mbugani soils, whichiii were deficient of this element. Field experiments are recommended to confirm these initial findings.
Assessment of the impacts of climate variability and change on rainfed cereal crop productivity in central Tanzania
(Sokoine University of Agriculture, 2015) Msongaleli, Barnabas M.
Though production of cereal crops in Tanzania could succumb to the projected climate change, research has mainly focused on maize (Zea mays L), the main staple crop for the country, and just little work has been done to analyse climate change impacts specifically on sorghum [Sorghum bicolor (L) Moench]. This study analysed the nature and sources of vulnerability on sorghum production by smallholder farmers due to climate variability and change and evaluated possible farm-level adaptation options that can enhance the adaptive capacity of smallholder farmers in the face of increased climate variability and long-term change in climate. The study was conducted in Dodoma and Singida regions in central Tanzania. Local famers‟ management practices from databases and surveys were combined with field experimentation and simulation modelling. The Agricultural Production Systems SIMulator (APSIM) and Decision Support System for Agro-technological Transfer (DSSAT) models were calibrated and validated to predict growth and yield of sorghum under rainfed conditions in the case study regions. Three sorghum varieties: Macia, Pato and Tegemeo were used. The models were parameterized using different agronomic parameters (phenological development, dry matter accumulation and grain yield) and climatic data. Efficiency of the models were tested using model validation skill scores including d-stat, root mean square error (RMSE) and regression coefficient (R 2 ). To understand the nature of vulnerability, long term historical rainfall data were analysed. Simulations were conducted to evaluate the impacts and interactions of adaptation options, namely: staggered planting dates, recommended planting density, and variable fertilizer rates on sorghum and maize yields under long-term climate change towards the mid-century. The long-term rainfall analysis shows that total annual rainfall has so far notiii changed, but variability in the rainfall distribution within seasons has increased. Experimentation in this study demonstrated that the tested sorghum varieties had variable maturity dates and different responses to prolonged dry spells. Thus, the early maturing variety Macia (102 days) was able to avoid terminal drought versus Pato (118 days) and Tegemeo (114). Statistical analysis show a significant (at 0.05 level) inter-seasonal effect on grain yield and total biomass of the sorghum varieties. Agricultural production systems in semi-arid central Tanzania are projected to be affected by expected changes in climatic conditions over the next decades and century. Simulation results show that Macia will not be affected by climate change. In contrast, early maturing maize variety Situka was not able to compensate for the decline in yield under climate change. However, fertilizer application increased Situka yield significantly under future climates particularly when early planting was adopted. Coupled with increasing population pressure and declining soil fertility, climate variability and change are relentless driving forces to reduce agricultural productivity in the near future. Because agriculture causes a variety of benefits and challenges, impacts of climate change on agricultural systems are of importance from an economic but also from a social and environmental point of view. Assessment of impacts and potential adaptation supports the decision making processes of farmers, governments, and other stakeholders. Adaptation options such as changes in sowing dates, changes in planting density and fertilizer application were evaluated. To adapt to the changing climate, early sowing and increasing plant density per hectare and fertilizer application would be feasible options. The selection of an earlier sowing date for maize, for instance, would be the appropriate response to offset the negative effect of increased temperature. This change in planting date would allow for the crop to develop during a period of the year with loweriv temperatures, thereby decreasing developmental rates and increasing the growth duration, especially the grain filling period. The study also found that site specific agro-ecological conditions such as soil type characterize farmers‟ responses to decisions on the type of crop and/or crop variety to grow in a given season. This is partly due to their perceptions on soil fertility status among soil types taking spatial variability across the fields into account. Other socio-economic factors ranging from food tastes and preferences to markets and prices, variably but strongly influence decisions on continued adoption of drought tolerant crops (sorghum and millets) versus the susceptible maize. The results show that these factors and associated challenges have the potential to bring negative externalities, therefore, efforts to minimize the impacts from climate variability and change should go alongside with addressing the reported perception and preference challenges. Soil fertility management is therefore likely to be a major entry point for increasing the adaptive capacity of smallholder farmers to climate change and increased climate variability. However, management of other factors related to improved varieties, nutrient resource access and socio-economic factors is critical for rainfed cereal production under changing climate. This dissertation addresses impacts and adaptation to climate change on sorghum production (with some comparison with maize) in the central zone of Tanzania. An overview over different approaches of modelling climate change impacts on crop production as well as a review of studies that analyse climate change impacts on agriculture in sub-Saharan Africa and Tanzania in particular are given in the introductory Chapter 1. Chapter 2 describes the evaluation of the performance of three sorghum varieties at the field level and assessment of their performance over a long-term period using biophysical modelling. In Chapter 3, an approach that integrates the biophysical modelsv DSSAT and APSIM model with GCMs is used to analyse the impact of climate change on sorghum and maize production. Chapter 4 investigates the influence of driving factors separate from impacts of climate change on the production of sorghum relative to other cereals important in the zone. General discussion and conclusions are given in Chapter 5.
Assessment of the nitrogen and phosphorus needs and use efficiencies for enhanced maize yields in Mbozi district of Tanzania
(Sokoine University of Agriculture, 2014) Liduke, L.
A study was conducted in Lumbila, Senjele, Mbimba and Ihowa villages of Mbozi district, Tanzania during 2012 – 2013 cropping season to assess the fertility status of the soils and response of maize to N and P as a strategy for enhanced and sustainable maize production. This study was triggered by the low maize yield in Tanzania due to many factors which include declining soil fertility, soil N and P being the major constraints to maize production. The search for the most appropriate rate of N and P fertilizers in relation to maize that would result in optimum yields prompted this research to be conducted. The experiment was laid as Randomized Complete Block Design with three replications. Maize variety used was “UH 615” with fertilizer treatments of Urea (46%N) and TSP (46% P2O5). Based on the soils analytical data, the major soil limitations for increased and sustainable maize production at the study areas include the deficiencies of N, P, Ca, Zn and low in OM. Application of 80 kg N ha-1 + 20 kg P ha-1 and 120kg N ha-1 + 20 kg P ha-1 significantly (P ≤ 0.05) enhanced maize growth and yield more than other treatments, however, the effect was insignificant on harvest index of maize. Application of N at the rates of 40, 80 and 120 kg ha-1 and combining each rate with 20, 40 and 60 kg P ha-1 reduced NUE while increased PUE of maize in all experimental sites. These findings suggest that as NUE decreased the PUE is increased. This could be related to the increase in N and P imbalances in soils as the rates of N applied increased. Results also indicated an inverse relationship between the higher doses of fertilizer application and benefit cost ratio. Application of 80 kg N ha-1 + 20 kg P ha-1 and 120kg N ha-1 + 20 kg P ha-1 produced the highest maize yields equivalent to 4.4 and 4.2 t ha-1 with the gross return of 2,112,000/= TSh and 2,020,800/= Tsh ha-1 with respect to BCR, respectively. This study further confirmed the role of N and P fertilizers in increasing growth and grain yield in maize production. From these results application of 120kg N ha-1 + 20 kg P ha-1 may be recommended for increasing maize yields particularly in the study areas. However, application of 80 N ha-1 + 20 kg P ha-1 can also increase in the yield of maize. This will greatly benefit farmers in Mbozi district where the supply of N fertilizer is low and cases where farmers cannot afford the cost of high fertilizer input. It is also recommended that while there is a wide-scale adoption of blanket fertilizer recommendation there is a need for site-specific nutrient management for balanced fertilization.
Assessment of the potential of Siam weed (Chromolaena odorata) in enhancing soil fertility status in Serengeti District, Tanzania
(Sokoine University of Agriculture, 2015) Mbalila, Schola
Siam weed (Chromolaena odorata) is a plant that has infested a large area of agricultural land in Serengeti district and has adversely reduced crop land and crop yields. It is encroaching land and especially in the famous Serengeti National Park. The weed has been reported to contain high amount of plant nutrients in its tissue, hence its probable use as an organic soil amendments, with aspect to soil fertility improvement. A study was, therefore, conducted to address the Siam weed growth requirements, nutrient contents in its tissue and its suitability and use as an organic amendments as a way to manage the weed accordingly and appropriately. Soil and Siam weed plant sampling was done in the Serengeti district (Mara Region), an analysis was done in the Soil Science laboratory at SUA, Morogoro. Composite topsoil (0 – 20 cm) samples were collected and analysed for physico-chemical properties hence shows to have slightly acidity with pH (5.8 to 6.5), low to high CEC (11.6 - 29.4 cmol (+) kg −1 ) and very low to very high soil organic carbon (0.36 - 3.69%). Three soil profiles on a toposequence from the infested soil were excavated, described and sampled for soil laboratory analysis, hence shows medium acidic to medium alkaline (pH 5.84 to 7.93), low to high CEC (10.12 - 35.20 cmol (+) kg -1 ), low to medium SOC (0.11 - 1.97%) and high exchangeable bases 24.45 cmol (+) kg −1 based on the rating by Landon (1991). Using the morphological and laboratory data the soils were classified to the subgroup level of the USDA Soil Taxonomy as Ustic Torripsamments on sloping land, as Haplic plinthustults on midslope and as Plinthaquic paleudalfs on low land and to Tier-2 of WRB as Rendzic Lithic Leptosols (Eutric, Dystric, Tephric) on sloping lands, as Gleyic Plinthic Acrisols (Ferric, Humic) on midslope and as Haplic Stagnic Gleyic Luvisols (Chromic) on low or flat areas. Incubation study was done by incorporation of different parts of Siam weed plant with soil for 16 weeks. As a result of mineralization after incubation, the leaves released N (0.292%) and Fe (64.15 mg kg -1 ); bulbs released P (12.39 mg kg -1 ) and Mg (0.87Cmol (+) kg -1 ); stems released K0.22 cmol (+) kg -1 ) and Ca (5.13 cmol (+) kg -1 ) and roots released Cu (6.01 mg kg -1 ), Mn (77.18 mg kg -1 ) and Zn (1.65 mg kg -1 ). Nutrients released were increasing from the 0 to 12 th week and started to decrease at week 16 after incubation. Therefore, from incubation results, it is recommended that, farmers should grow their crops before the 12th week following incorporation of Siam weed biomass into soils for plants to absorb nutrients from the Siam weed.
Assessment of uranium levels in selected soils and its uptake by rice, maize and millet in Bahi district, Tanzania
(Sokoine University of Agriculture, 2014) Makoti, Clavery Atiianas
This research aimed to determine levels of uranium (U) contamination in selected agricultural soils of Bahi District and its uptake by food crops in order to enhance public awareness and safety. The research involved determination of spatial distribution of U in agricultural soils, its uptake and translocation in plant/crop tissues. Soil, plant and water samples were collected randomly from farmers' fields and water sources, respectively. Laboratory sample analysis was done at the Government Chief Chemist Laboratory in Dar es Salaam and Soil Science Laboratory at the Sokoine University of Agriculture. Substantial differences of U concentrations in soils, plants and water were determined. The highest U level in soil profiles was 74.8 pg kg’1 at Mpamantwa and the lowest was18.3 pg kg’1 at Hindi. Along the studied transects, the highest U level was 743 pg kg’1 at Bahi and lowest was 13.6 pg kg’1 at Hindi. Uranium concentrations in maize and rice were below detectable limit (<10 pg L"1) except for finger millet where U accumulation levels ranged from 10.4 to 32.0 pg kg‘l. The concentration of U in water differed from village tovillage. The highest U level of 1233 pg L’1 was found in Hindi village at Hindi Playa Lake whereas in Bahi the highest U concentration was 62.9 pg L’1 found in one of the Bubu tributaries under the bridge. The concentrations of U in water in Hindi and Bahi villages were more than 30 pg L’1 the tolerable limit set by WHO for human and animal consumption. The levels of U in soils and crops were within the tolerable limit for agricultural use and the environment. Further studies should be carried out for other types of crops that are grown in the Bahi District villages to assess their safety for human consumption.
Assessment of uranium levels in waterand soils and its uptake by sorghum and sunflower in Singida Urban District, Tanzania
(Sokoine University of Agriculture, 2016) Kaishwa, S. J.
In Tanzania, uranium deposits have recently been found in Bahi and ManyoniDistricts. Due to suspected high uranium levels in water sources as reported by District water authoritiesin Singida District, this study was carried out to determine levels of uranium in soils, and water and its uptake by commonly grown food cropsfor enhancing public awareness and safety to the residents of Singida Urban District. Rock, soil and plant samples were collected randomly from farmer’s field.Water samples were collected from various water sources in Singida Urban District. Laboratory analyses of soil, rock and plant samples werecarried out at the Geological Survey of Tanzania in Dodoma and Soil Science laboratory at Sokoine University of Agriculture while water samples were analysed atthe Government Chief Chemist Laboratory in Dar es Salaam. Results foundin soil, water, and rocks. The highest U level in soil of 15.4mg kg-1was obtained at Burudani area and the lowest level of<0.01mg kg-1was obtained at Kwa Askofu area. The concentration of uranium in rocks ranged from 20.1 to 31.5 mg kg-1, which in some places washigher than the critical level of 23 mg kg-1 recommended for agricultural land use. Uranium concentrations in sorghum and sunflower grainswere found torange from 1.4 to 5.2 mgkg -1, while in leaves it was less than 2.3 mgkg -1. Uranium concentrations in water ranged from 0.058 to 1.097 mgL-1, the values which were higher than 0.03 mgL-1tolerable limit set by WHO for human and animal consumption. It was concluded that uranium contents found in soils are within the tolerable limit set for agricultural use and consequently sorghumand sunflower grown in the District are safe for human and animal consumption. Most water sources in the District had higher levels of Uranium and thus, should not be used for safety reasonsunless they are treated to reduce uranium concentration. Further studies are recommended to assess uranium concentration in fish, and soda ash,which are produced from lakes and in Singida Urban District.

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