Browsing by Author "Mrema, J. P."
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Item Contribution of legume rotations to the nitrogen requirements of a subsequent maize crop on a rhodic ferralsol in Tanga, Tanzania(2013) Marandu, A. E. T.; Semu, E.; Mrema, J. P.; Nyaki, A. S.Industrial fertilizers are expensive for small-scale farmers who, as alternative, rely on legume crops for providing N for a subsequent maize crop. A legume-maize rotational experiment was carried out on a Rhodic Ferralsol at Mlingano Agricultural Research Institute in Muheza, Tanga, Tanzania, to evaluate the effects of legumes rotation in meeting the N fertilizer requirements of maize. The experimental site was located at 39o 52’E, 5o 10’S and 183 metres above sea level (m.a.s.l.). The experiment was conducted for two rotation cycles whereby cowpea, pigeonpea or greengram were grown during the short rains followed by maize during the long rains. The maize rotations were imposed on plots on which legumes had been grown during the previous legume rotation. Monoculture maize was grown with treatments of 0, 25, 50 and 100 kg N ha-1 imposed for purposes of plotting N fertilizer response curves. Based on the response curve lines, the effects of the legume rotation on maize yields were compared and translated as N fertilizer equivalency of the legumes in question. The grain and residue yields of the three legumes were significantly different (P<0.01), a fact which was attributed to the genetic differences of the legume species. The maize yields following rotation with each of the three legumes were significantly higher (P<0.05) than those under continuous maize. The effects of the rotations on increasing the maize yields were equivalent to application of 25, 19 and 16 kg N ha-1 for the cowpea, pigeonpea and greengram rotations, respectively. It was, however, concluded that the contributions of N by the legumes in the legume-maize rotations were not enough to satisfy the maize N requirements of 50 kg N/ha; hence supplementation with mineral N, in addition to the rotations, is necessary for increased yields.Item Developing a coffee yield prediction and integrated soil fertility management recommendation model for Northern Tanzania(International Journal of Plant & Soil Science, 2014-02-14) Maro, Godsteven, P.; Mrema, J. P.; Msanya, B. M.; Janssen, Bert, H.; Teri, James, M.The aim of this study was to develop a simple and quantitative system for coffee yield estimation and nutrient input advice, so as to address the problem of declining annual coffee production in Tanzania (particularly in its Northern coffee zone), which is related to declining soil fertility. The study was conducted between 2010 and 2013 at TaCRI Lyamungu, with source data taken from Hai and Lushoto districts, Northern Tanzania. An earlier model QUEFTS, developed for maize but under similar conditions as those of Arabica coffee (Coffea arabica) in the study areas was used as a benchmark. Secondary fertilizer trial data were used in model calibration for coffee, while adding two more steps related to balanced nutrition and the economics of integrated soil fertility management (ISFM). Primary soil analytical data and calculated yields on basis of tree number were used for model testing. The result was a new model which we hereby call SAFERNAC (Soil Analysis for Fertility Evaluation and Recommendation on Nutrient Application to Coffee). The model consists of three modules: SOIL (the soil properties of interest), PLANT (all the crop and crop management parameters such as physiological nutrient use efficiency, plant density, maximum yields per tree) and INPUT (nutrient inputs – organic and inorganic). It consists of two subsequent parts – a baseline approach (no input) for coffee land evaluation; and an integrated soil fertility management (ISFM) approach that involves application of nutrient inputs, for ISFM planning and design of fertilizer experiments. The model was checked for accuracy of the adjusted equations, and found to be capable of reproducing the actual yields by 80-100%. The new model is a useful tool for use in coffee farms.Item Exploring the nutrient release potential of organic materials as integrated soil fertility management components using SAFERNAC(International Journal of Plant & Soil Science, 2014-02-18) Maro, Godsteven, P.; Mrema, J. P.; Msanya, B. M.; Janssen, Bert, H.; Teri, James, M.The aim of this study was to establish the nutrient release potential of different organic materials and assess their role in integrated soil fertility management for coffee using the new coffee yield model SAFERNAC. It involved an incubation experiment conducted at TaCRI Lyamungu Screenhouse for 180 days between April and September 2011. Cattle manure, coffee leaves, pulp and husks, Albizzia leaves and four green manure plants – Mucuna pruriens, Lupinus albus, Canavalia ensiformis and Crotalaria ochroleuca were mixed with two soil types – Eutric Nitisols from Lyamungu, Hai district and Humi-Umbric Acrisols from Yoghoi, Lushoto district. The mixing ratio was 5% organic to soil, the mixture was moistened to FC and incubated in 10 litre plastic containers arranged in RCBD (10 treatments and 3 replications) at room temperature. Duplicate soil samples + were taken at day 0, 3, 8, 15, 26, 45, 74, 112 and 180 and analyzed for NH 4 -N, NO 3 -N, available P and exchangeable K. The cumulative N min , P and K values resulting from the treatments were used to estimate their relative contribution to the soil nutrient pool and later exposed to the new model SAFERNAC for yield estimation under different nutrient management options (1 to 10 tons organics per ha alone on one hand and supplemented with 160 kg N, 60 kg P and 160 kg K). The tested organics differed significantly (P<0.001) in their N min, P and K release in the two soil types. They also differed in their substitution values and therefore the amounts of nutrients each one can contribute to the soil nutrient pools. Green manures showed about ten times higher potential as compared to cattle manure. Four of them (Crotalaria, Mucuna, Canavalia and Lupine) were picked as best bets for inclusion in the coffee ISFM programme. SAFERNAC recommended a number of nutrient management options involving the test organics and the two soil types under organic and conventional coffee farming.Item Farmers’ perception of soil fertility problems and their attitudes towards integrated soil fertility management for coffee in Northern Tanzania(Journal of Soil Science and Environmental Management, 2013-09) Maro, Godsteven P.; Mrema, J. P.; Msanya, B. M.; Teri, James M.A study was conducted in Hai and Lushoto districts, Northern Tanzania to establish the farmers’ perception of soil fertility problems and their attitudes towards integrated soil fertility management (ISFM) for coffee, thereby identifying the appropriate intervention strategies. The study was based on a structured questionnaire involving 126 respondents. Both farmers’ awareness of the problem and their attitudes were highly significant (at p<0.01). Age, household size, and adoption of improved coffee varieties, affected farmers’ awareness significantly (p<0.05). As for farmers’ attitudes, six of the eight predictors were significant (p<0.05). Age, household size, adoption of new varieties and total farm income were highly significant (p<0.01). Age, total land under coffee and total off-farm income negatively affected farmers’ attitudes. As farmers get older, they tend to refrain from innovation. Larger farms are likely to exert more pressure on the available organic resources. With multiple farms, distant farms are likely to receive less attention. When off-farm income was considered, multiple ventures compete for the farmers’ time, resources and attention. For the two districts, ISFM interventions will make a better impact to younger and more energetic farmers with sufficient lands for commercial coffee production and to farmers who depend largely on this resource for their livelihood.Item Pedological characterization of typical soil of Dakawa Irrigation Scheme, Mvomero District, Morogoro Region, Tanzania(EXCELLENT PUBLISHERS, 2017) Mbaga, H. R.; Msanya, B. M.; Mrema, J. P.This study was conducted to characterize dominant soil type at Dakawa Irrigation Scheme (DIS), Tanzania. Typical soil at DIS was identified, excavated and described using FAO (2006) Guidelines. Six disturbed samples were taken from soil profile horizons together with three undisturbed core samples for laboratory analysis. The pedon developed from Neogene alluvial parent materials under ustic moisture and isohyperthermic temperature regimes. The pedon was very deep (> 150 cm), moderately well drained, with gray to very dark gray soil colours. CaCO3 concretions characteristic of calcic horizon were observed in subsoil. Soil texture was sandy clay loam throughout the pedon. pH was rated as medium (5.5 - 7.0) to very high (7.0 - 8.5) respectively for topsoil and subsoil. OC and N levels were very low; CEC and exchangeable bases were low to medium. Bulk densities were high (1.8 gcm-3) to very high (>1.9 gcm-3) for topsoil and subsoil, respectively. Study on moisture retention properties showed that subsurface (95 - 100 cm) and intermediate (45 - 50 cm) horizons retained more water than surface (0 - 5 cm) soil, congruent with increasing clay content with depth. According to Soil Taxonomy and World Reference Base for Soil Resources, pedon at DIS classified as Vertic Calciustepts and Haplic Vertic Cambisols, respectively. These taxa reflect properties that may guide use and management of soils at DIS including selection of crops and fertilizers and rates to use. Organic fertilizers were recommended to increase organic matter content in soil. Use of acidifying inorganic fertilizers and gypsum as soil amendments should also be taken onboard to correct emerging sodicity.Item Phosphorus adsorption and its relation with soil properties in acid soils of Western Kenya(Department of Soil Science Sokoine, University of Agriculture, Tanzania., 2014-10) Muindi, E. M.; Mrema, J. P.; Semu, E.; Mtakwal, P. W.; Gachene, C. K.; Njogu, M. KLow available phosphorus (P) is one of the major hindrances to crop production in acid soils of western Kenya. Although considerable work has been done to establish P levels in the region, there is paucity of information on which to base fertilizer recommendations due to potential crop production differences caused by different soil types and climate. Phosphorus adsorption capacity and its relationship with some soil properties were evaluated in acid soils from nine locations of western Kenya. Adsorption data was obtained by equilibrating the nine soil samples with 30m1 of KH2PO4 in 0.01 M CaCl2, containing 0, 80, 150 and 300 pg m1-1 for 48 hours with shaking for 30 minutes at intervals of 8 hours. Langmuir, Freundlich and Tempkin adsorption models were fitted to the test results and relationship between P adsorption and soil properties determined by correlations. The result of this study showed that the soils were strongly to extremely acidic (pH 4.83 - 3.76), had high exchangeable Al3+ (>2 cmol Al kg-1), Al saturation of (> 20% Al) and calculated maximal phosphorous adsorption varied from 770.83 to 1795.83 mg kg' soil. Comparing the models, Freundlich linear model showed a better fit to the tested soils compared to Langmuir and Tempkin models. The regression coefficients (R2) for the fitted Freundlich P adsorption isotherms was highly significant ranging from (0.995- 1.000) for all tested soils. Analysis of relationship between adsorption maximum and soil attributes revealed that adsorption maximum positively correlated with clay content, exchangeable P, exchangeable acidity and Aluminium saturation and negatively correlation with organic matter and electrical conductivity. Due to differences in maximal P sorption capacities within the tested area, blanket P fertilizer recommendation may affect crop productivity in some sites. There is therefore need for further research to determine optimal Phosphorus requirements for soils in each research site.Item Quantification of atmospheric n2 fixed by cowpea, pigeonpea and greengram grown on ferralsols in Muheza District, Tanzania(2010) Marandu, A. E. T.; Semu, E.; Mrema, J. P.; Nyaki, A. S.Legume crops are usually intercropped with cereals in small-scale farming systems in Tanzania. This aims at taking advantage of legumes to replenish soil nitrogen (N due to legumes’ N2 fixation). Glasshouse pot experiments and field trials were carried out atMlingano Agricultural Research Institute in Tanga, Tanzania, with the objective to find out how much N2 can be fixed by cowpea, pigeonpea and greengram using native Rhizobia, thus substituting for the use of N-mineral fertilizers in maize production on Ferralsols. In the glasshouse pot experiment, the legumes were grown in 5L plastic pots for 40 days in soil sampled from 0 – 20 cm layer. The field experiment was maize – legumes intercropping whereby the N2 fixation assessment was done 35 days after planting. In both cases, maize (Katumani variety) was the non- N2- fixing reference crop. The legumes formed effective nodules with the native Rhizobia. Different quantities of N2 gas were fixed by the different legumes, the differences being attributed to the legumes’ differences in their genetic characteristics. In the field, monocropped cowpea, pigeonpea and greengram fixed 38, 21, and 49 kg N2, respectively. In the intercrop system cowpea, pigeonpea and greengram fixed 16, 4, and 24 kg N2, respectively. In both cases, the quantities of N2 fixed were less than 50% of their total N accumulation. It was concluded that in Muheza, maize grown in association with the legumes would continue to need supplementation of mineral N fertilizer to maximize its yields.Item Response of rice to nitrogen and phosphorus applied on typical soils of Dakawa Irrigation Scheme, Morogoro, Tanzania(Imperial Journal of Interdisciplinary Research (IJIR), 2017) Mbaga, H. R.; Mrema, J. P.; Msanya, B. M.A screen-house pot experiment was conducted at Sokoine University of Agriculture, Morogoro, Tanzania to assess response of rice variety TXD 306 growth parameters to nitrogen and phosphorus applied to the dominant soil type at Dakawa Irrigation Scheme (DIS) Morogoro, Tanzania. The study was prompted by low rice yields and the need to find out the soil constraints to high rice production at the scheme. Based on physical, chemical and biological properties of composite soil sample, the soil had low total N, OC, exchangeable Ca and Mg, hence rated as marginally to moderately suitable for rice production. N and P rates adopted were 0, 50,100, 150, 200 kg N ha-1 and 0, 40, 80, 120, 160 kg P ha-1, respectively. Sources of N and P were (NH4)2SO4 and Ca(H2PO4)2, respectively applied in a 52 factorial in CRBD. Number of tillers increased significantly (p < 0.05) with N and P levels from P0N0 kg ha-1 to P80N200 kg ha-1. Biomass weight (g) increased significantly (p<0.05) from 10.99 g pot-1 to 93.04 g pot-1 at P0N0 kg ha-1 and P160N200 kg ha-1, respectively. Grain yield (g) increased significantly (p<0.05) from 2.24 g pot-1 to 33.06 g pot-1 for the absolute control and P160N200 kg ha-1, respectively. Thus, for optimum grain yield of TXD 306 on Cambisols at DIS, 80 kg P ha-1 should be applied as basal and N in two splits i.e. 100 kg N ha-1 close to tillering and 100 kg N ha-1 at panicle initiation. For appropriate N and P recommendations, field studies should be conducted to take onboard integrated soil fertility management strategies, principles and practices in rice cultivation based on soil types to allow extrapolation of the results to other similar soils and areas.Item Soil acidity management by farmers in the Kenya highlands(2016-11) Muindil, E. M.; Semu, E.; Mrema, J. P.; Mtakwa, P. W.; Gachene, C. K.Declining soil fertility attributed to soil acidity is a major soil productivity problem in sub-Saharan Africa. A study was carried out in nine counties across the Kenya highlands, namely Meru, Embu, Kerugoya, Nyeri, Kiambu, Kinangop, Siaya, Busia and Eldoret, where the problems associated with soil acidity are prominent. The study aimed at assessing farmers' awareness of soil acidity, and establishment of common acidity management practices following administration of structured questionnaires. From the information gathered through personal interviews via questionnaires, <37% of the farmers were attached to a farmers training group in all study sites; among them, <4% were aware of soil acidity problems and <8% had carried out chemical analysis of their soils. The farmers who had applied lime at least once on their farms were <3% in all sites. Most farmers (>80%) used both inorganic fertilizers and manure on their farms, with the majority using DAP, CAN and farmyard manure. On cultural soil fertility management, choice of subsequent crop was dictated by sustainability rather than cropping system like rotation. There was a significant (P<0.05) negative relationship between livestock keeping and soil fertility management, with <30% of the farmers returning crop residues back to the farm. Most of them fed crop residues to their livestock. Only 8% of the farmers incorporated crop residues into the soil. There was a significant (Ps 0.05) positive correlation between education level and inorganic fertilizer use in crop production. Farmer's age and maize yields correlated negatively with each other. Additionally, farmers' training programmes and frequencies positively influenced choice of inorganic fertilizers and levels of application. Training is therefore one of the most significant issues affecting soil fertility management in the Kenya highlands. To further enhance the understanding of soil acidity and fertility management in Kenya highlands, farmers training should be prioritized.Item Soil acidity management by farmers in the Kenya Highlands(Sokoine University of Agriculture, Tanzania., 2015-10-10) E. M. Muindi, E. M.; Semu, E.; Mrema, J. P.; Mtakwa, P. W.; Gachene, C. K.Declining soil fertility attributed to soil acidity is a major soil productivity problem in sub-Saharan Africa. A study was carried out in nine counties across the Kenya highlands, namely Meru, Embu, Kerugoya, Nyeri, Kiambu, Kinangop, Siaya, Busia and Eldoret, where the problems associated with soil acidity are prominent. The study aimed at assessing farmers' awareness of soil acidity, and establishment of common acidity management practices following administration of structured questionnaires. From the information gathered through personal interviews via questionnaires, <37% of the farmers were attached to a farmers training group in all study sites; among them, <4% were aware of soil acidity problems and <8% had carried out chemical analysis of their soils. The farmers who had applied lime at least once on their farms were <3% in all sites. Most farmers (>80%) used both inorganic fertilizers and manure on their farms, with the majority using DAP, CAN and farmyard manure. On cultural soil fertility management, choice of subsequent crop was dictated by sustainability rather than cropping system like rotation. There was a significant (P<0.05) negative relationship between livestock keeping and soil fertility management, with <30% of the farmers returning crop residues back to the farm. Most of them fed crop residues to their livestock. Only 8% of the farmers incorporated crop residues into the soil. There was a significant (Ps 0.05) positive correlation between education level and inorganic fertilizer use in crop production. Farmer's age and maize yields correlated negatively with each other. Additionally, farmers' training programmes and frequencies positively influenced choice of inorganic fertilizers and levels of application. Training is therefore one of the most significant issues affecting soil fertility management in the Kenya highlands. To further enhance the understanding of soil acidity and fertility management in Kenya highlands, farmers training should be prioritized.Item Soil fertility evaluation for coffee (Coffea arabica) in Hai and Lushoto districts, Northern Tanzania(International Journal of Plant & Soil Science, 2014-05-14) Maro, Godsteven, P; Msanya, B. M.; Mrema, J. P.The aim of this study was to evaluate the soil fertility status of selected coffee growing districts of Northern Tanzania and recommend immediate and long term soil management intervention strategies. The study was conducted in Hai and Lushoto Districts, between May and September, 2011. A total of 116 soil augerings and 10 soil profiles were described, and soil samples analyzed for the key fertility parameters. These were evaluated qualitatively by assigning scores against the requirements of Arabica coffee, and quantitatively by calculating the total soil-available nitrogen, phosphorus and potassium. Spatial assessment of the total soil-available nutrients was done using ArcView GIS 3.2 and ArcGIS 9.3. Soil fertility was found to be considerably low in the study areas, much lower in Lushoto than in Hai. Limitations common to both districts are low P and micronutrients, while the additional ones specific for Lushoto are low cation exchange capacity and exchangeable K. Spatial interpretation revealed interesting trends, which could be explained from the topography of the area and/or the farming practices common in the area. The results are discussed in this paper, and recommendations on appropriate integrated soil fertility management strategies are put forward.