Peter Mtakwa | Sokoine University of Agriculture (original) (raw)

Papers by Peter Mtakwa

Hydrological Processes, 1987

ABSTRACT

The inclusion of legume crops in cropping systems has been shown to improve soil fertility and pr... more The inclusion of legume crops in cropping systems has been shown to improve soil fertility and productivity, but the adoption rate is low among many smallholder farmers. A study to determine the perceptions of the smallholder farmers on groundnut production, use of inputs and cropping systems was conducted in Chisamba District, Zambia. Using a multi-stage sampling technique, 164 farmers from 20 villages within 11 agricultural camps in two agricultural blocks were randomly chosen for the study. Questionnaires were administered to only smallholder farmers who cultivated groundnuts. Results showed that the cropping systems used by smallholder farmers in Chisamba District were crop rotation (90%), mixed-intercropping (5%) and sole-cropping (5%). Groundnut production was mainly undertaken by female smallholder farmers (71%) on land averaging 1.68 ha. However, there was non-significant relationship between gender of the household head and adoption of cropping system (χ 2 (2) = 1.726; p = 0.414). Fifty-seven percent of the smallholder farmers perceived the groundnut variety Natal Common to be most suitable for the study area (χ 2 (4) = 9.745; p = 0.045). It was concluded that particular traits of varieties affected the perceptions and hence adoption decisions of smallholder farmers in Chisamba District.

Low available phosphorus (P) is one of the major hindrances to crop production in acid soils of w... more Low 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 30ml of KH 2 PO 4 in 0.01 M CaCl 2 , containing 0, 80, 150 and 300 µg ml -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 Al 3+ (>2 cmol Al kg -1 ), Al saturation of (> 20% Al) and

American Journal of Experimental Agriculture, 2015

The study was conducted to evaluate effects of conservational tillage on vegetable production on ... more The study was conducted to evaluate effects of conservational tillage on vegetable production on the north-eastern part of Uluguru Mountains in Tanzania. Six treatments such as control conservational tillage; conservational tillage with manure; conservational tillage with insitu composting; control traditional tillage; traditional terrace with manure and traditional tillage with in situ composting were examined. Nutrient levels were determined from soil before and after harvest and from plant samples after harvest. Soil losses were assessed by collecting runoff using polyethylene troughs for each treatment. Analysis of variance and Multiple range test (P=0.05) was done to test the effect of the treatments. The differences (P=0.05) on soil loss, plant nutrient status and vegetable yield were observed. All conservational treatments gave high fresh yield (4.3 - 44.7 ton/ha), high nutrient retention (N% 0.11 - 0.14, P% 5.17 - 16.33, K% 0.33 - 0.36) and experienced low soil losses (0.49,...

Groundwater first started to be used as a source of water supply for the Dar-es- Salaam City in 1... more Groundwater first started to be used as a source of water supply for the Dar-es- Salaam City in 1943. However, many of the existing boreholes in Dar-es-Salaam were drilled in 1997 after Tanzania experienced a severe drought; since then groundwater use in the city shows an increasing trend and currently over 50 percent of residents in Dar es Salaam City relies on groundwater supply. Today, there are more than 10000 boreholes for domestic, water supply and industrial purposes. Demand and reliance on groundwater from a growing population along the coast raises the need to increase efforts to protect and manage the resource. In the coastal aquifer of Dar-es-Salaam, groundwater quality is influenced by various potential sources of salinity that determine the composition of water extracted from wells. The results show that the origin of salinity in the area is strongly influenced by: groundwater ascending from deep marine Miocene Spatangid Shales through faults, saltwater intrusion on the...

International Journal of Plant & Soil Science, 2015

Among the various soil erosion processes threatening sustainable agriculture, soil losses due to ... more Among the various soil erosion processes threatening sustainable agriculture, soil losses due to root, tuber and bulb harvesting are poorly documented, particularly in tropical environments. A study was thus conducted in two villages with contrasting agro-ecological conditions on Acrisols and Fluvisols in Western Usambara Mountains, Tanzania. The aim was to investigate the mass of soil and nutrients lost and the factors influencing variation of soil loss due to crop harvesting (SLCH) for Carrot (Daucus carrota), Onion (Allium cepa L.) and Potato (Solanum tuberosum L.) Mwango et al.; IJPSS, 4(1): 18-28, 2015; Article no. IJPSS.2015.002 19 under low input agriculture. A total of 108 farm plots were sampled from the two villages. The mean SLCH values were significantly higher for carrot (7.1 Mg/ha/harvest) than for onion (3.8 Mg/ha/harvest) than for potatoes (0.7 Mg/ha/harvest). Soil nutrient losses in kg/ha/harvest were higher for carrot than for onion and potatoes (e.g. 30 N, 0.1 P, 1.5 K for carrot vs 6.3 N, 0.04 P, 0.2 K for onion) in Majulai village. SLCH was greater in Migambo (humid cold) than in Majulai (dry warm) for all the studied crops. Soil water content at harvest time played a significant (P = .05) role in inducing SLCH for onion while bulk density for carrot, whereas for potato they were not significantly influenced by soil water content and bulk density. Soil texture played only a minor role to SLCH of the studied crops. The observed soil and nutrient losses in the current study are substantial and pose a challenge that calls for immediate attention to the harvesting practices in the study area. However, combating water erosion is far more urgent.

Land Degradation & Development, 2014

ABSTRACT Soil erosion is a major threat to food security in rural areas of Africa. Field experime... more ABSTRACT Soil erosion is a major threat to food security in rural areas of Africa. Field experiments were conducted from 2011 – 2014 in Majulai and Migambo villages with contrasting climatic conditions in Usambara Mountains, Tanzania. The aim was to investigate the effectiveness of mulching in reducing soil erosion and restoring soil fertility for productivity of maize (Zea mays) and beans (Phaseolus vulgaris) under miraba, a unique indigenous soil conservation measure in the area. Soil loss was significantly higher (p < 0.05) under miraba sole than under miraba with mulching e.g. 35 vs 20 and 13 vs 8 Mg ha-1 year-1 for Majulai and Migambo villages, respectively, in 2012. Soil fertility status was significantly higher (p < 0.05) under miraba with Tughutu mulching than under miraba sole e.g. 0.35 vs 0.25 % total N, 37 vs 22 mg kg-1 P and 0.6 vs 0.2 cmol (+) kg-1 K for Majulai village; 0.46 vs 0.38 total N, 17.2 vs 10.2 mg kg-1 P and 0.50 vs 0.2 cmol (+) kg-1 K for Migambo village. Maize and bean yields (Mg ha-1) were significantly higher (p < 0.05) under miraba with Tughutu mulching than under miraba sole, 2.0 vs 1.3 for maize and 0.9 vs 0.8 for beans in Majulai; 3.8 vs 2.6 for maize and 1.0 vs 0.8 for beans in Migambo village in 2012. This implies that Tughutu mulching is more effective in improving crop yield than Tithonia, though both could potentially protect the arable land from degradation caused by water erosion under miraba. This article is protected by copyright. All rights reserved.

International Journal of Plant & Soil Science, 2014

ABSTRACT Plant roots may have a strong erosion-reducing effect. However, little is known about ro... more ABSTRACT Plant roots may have a strong erosion-reducing effect. However, little is known about root characteristics of tropical plants used for erosion control. A study was thus conducted in the Western Usambara Mountains, Tanzania to investigate rooting characteristics of Guatemala grass (Tripsacum andersonii), Napier grass (Pennisetum purpureum) and Tithonia shrub (Tithonia diversifolia), also referred to as wild sunflower, and to evaluate their potential for erosion control. For each plant species, mean root diameter (D), root density (RD), root length density (RLD) and root area ratio (RAR) were assessed for six plants in each species and relative soil detachment rate (RSD) predicted. Mean RD values in the 0 - 0.4 m soil depth for Majulai village and Migambo village respectively were 50.9 and 58.6 kg/m3 for Guatemala grass, 30.4 and 31.3 kg/m3 for Napier grass and 22.1 and 23.0 kg/m3 for Tithonia shrub. RLD values were 35.9 and 45.0 km/m3 for Guatemala grass, 31.3 and 150.0 km/m3 for Napier grass and 10.5 and 6.4 km/m3 for Tithonia shrub. Predicted RSD values were 4.43*10-12 and 1.20*10-14 for Guatemala grass, 6.10*10-5 and 2.74*10-4 for Napier grass and 4.43*10-3 and 2.24*10-4 for Tithonia shrub in the 0 - 0.4 m soil depth. The results indicate that Guatemala grass has a higher potential to reduce soil erosion rates by concentrated flow as compared to Napier grass or Tithonia shrub in the 0 - 0.4 m soil depth. These findings have implications on the selection and use of appropriate plants for soil erosion control.

Advances in Research, 2015

The Usambara Mountains in Tanzania are severely affected by soil erosion which has led to deterio... more The Usambara Mountains in Tanzania are severely affected by soil erosion which has led to deterioration of soil properties and reduced crop productivity. Indigenous soil erosion control measures such as miraba which are widely practised in the area have yielded little success. Field plot experiments were laid down in Majulai and Migambo villages from 2011 -2014 on typical soils of the

Journal of Agriculture and Ecology Research International, 2015

ABSTRACT Indigenous soil conservation measures such as miraba have been widely used in Usambara M... more ABSTRACT Indigenous soil conservation measures such as miraba have been widely used in Usambara Mountains for controlling soil erosion but with little success. On-farm runoff experiments were set from 2011–2014 on Acrisols in Majulai and Migambo villages with contrasting agro-ecological conditions in the Usambara Mountains, Tanzania. The aim was to investigate the effectiveness of miraba and miraba with various mulching materials in reducing runoff, soil and nutrient losses and improving productivity of maize (Zea mays) and beans (Phaseolus vulgaris). Results show that mean annual runoff coefficients (mm mm-1) ranged from 0.72 for cropland with no soil conservation measure (control) to 0.15 for cropland with miraba and Tithonia (Tithonia diversifolia) mulching in Majulai village and respectively from 0.68 to 0.13 in Migambo village. Soil loss was significantly (P = .05) higher under control than under miraba with either Tughutu (Vernonia myriantha) or Tithonia mulching e. g. 184 vs. 20 in Majulai and 124 vs. 8 Mg ha-1 year-1 in Migambo village in 2012. The Pfactors were significantly (P = .05) higher under miraba sole than under miraba with mulching in Majulai village (0.18 vs. 0.11) and in Migambo village (0.10 vs. 0.05).The annual nutrient losses in kg ha-1yr-1 were significantly (P = .05) higher under control than under miraba with mulching 367 vs. 37 total N, 0.8 vs. 0.1 P and 14 vs. 4 K for Majulai village; 474 vs. 26 total N, 0.7 vs. 0.1 P and 20 vs. 1.2 K for Migambo village in 2012. Maize and bean yields were significantly (P = .05) higher under miraba with Tughutu mulching than under control (e.g. 2.0 vs. 0.7 Mg ha-1 for maize in Majulai in 2012). Thus miraba with Tughutu mulching is more effective in improving crop yields than miraba with Tithonia and miraba sole.

Journal of Scientific Research and Reports, 2015

ABSTRACT Indigenous soil and water conservation (SWC) technologies such as miraba (rectangular gr... more ABSTRACT Indigenous soil and water conservation (SWC) technologies such as miraba (rectangular grass strip bounds that do not necessarily follow contours) and micro ridges have been used widely in the Usambara Mountains, Tanzania. However, their strengths and limitations to crop productivity have not been investigated. This study aimed to determine soil fertility and crop yield variability under miraba, micro ridges and bench terraces as a way to explore and compare these SWC technologies. A survey was carried out in Majulai watershed (with Acrisols as dominant soils) which is highly affected by soil degradation due to water erosion. Composite soil samples were collected from 0 - 30 cm depth in upper, middle and lower segments within bench terraces, micro ridges and miraba at the upper, mid and lower slopes of the watershed. Contents of most soil nutrients (e.g. available P, K+, Ca2+ and Mg2+) and maize grain yields varied significantly (P=.05) between SWC technologies, with the trend: bench terraces > micro ridges >miraba>control (fields with no SWC measures). Similarly under all SWC technologies soil fertility and maize grain yields varied significantly (P=.05) with slope position, showing the trend: lower slopes > mid slopes > upper slopes. Moreover, soil fertility and maize grain yields varied significantly (P=.05) between segments of the studied SWC technologies except for bench terraces. The trends for both soil fertility and maize grain yields were as follows: lower segments > middle segments > upper segments under micro ridges; lower segments > upper segments > middle segments under miraba. These observations call for management strategies and technological adjustments that would reduce pattern and magnitude of spatial variations of soil nutrients and crop yields under miraba and micro ridges for improved crop production in the Usambara Mountains.

International Scholarly Research Notices, 2014

A field study was carried out to evaluate the effects of tillage practices on soil physical prope... more A field study was carried out to evaluate the effects of tillage practices on soil physical properties in Mwala district, Eastern Kenya, during the long rains (LR) and short rains (SR) of 2012/13. The treatments were disc ploughing (DP), disc ploughing and harrowing (DPH), ox-ploughing (OX), subsoiling-ripping (SSR), hand hoeing with tied ridges (HTR), hand hoeing only (H). These were investigated under three cropping systems of sole maize, sole bean, and maize-bean intercrop in a split-plot design with four replications. Soil physical properties were monitored at different weeks after planting (WAP) throughout the growing seasons.

Journal of Agricultural Science, 2014

Soil water conservation through tillage is one of the appropriate ways of addressing soil moistur... more Soil water conservation through tillage is one of the appropriate ways of addressing soil moisture deficit in rainfed agriculture. This study evaluated the effects of tillage practices on soil moisture conservation and crop yields in Mwala District, Eastern Kenya during the long rains (LR) and short rains (SR) of 2012/13. Six tillage systems: Disc plough (MB), Disc plough and harrowing (MBH), Ox-ploughing (OX), Subsoiling -ripping (SR), Hand hoe and Tied Ridges (HTR) and Hand hoe only (H) and, three cropping systems namely, sole maize, sole bean and maize -bean intercrop, were investigated in a split-plot design with four replicates. Data on soil water content was monitored at different weeks after planting and the crop yields at end of each growing season. A three-season average shows that soil water content and crop yields were higher in conventional tillage methods compared to the conservation tillage methods. Long term tillage experiments are thus required at different locations, under various environmental and soil conditions to validate the study findings.

International Journal of Plant & Soil Science, 2015

A soil profile representative of typical soils of Mwala District, Kenya, was dug to study its mor... more A soil profile representative of typical soils of Mwala District, Kenya, was dug to study its morphology, soil physico-chemical characteristics and to classify it using two internationally known soil classification systems. Disturbed and undisturbed soil samples were taken from designated pedogenic horizons for physical and chemical analysis in the laboratory. Soil morphological observations revealed that the pedon is well drained and very deep with dark brown to dark yellowish brown topsoil overlying brown to strong brown sandy clay loam to sandy clay subsoil.

Soil and Tillage Research, 1996

Experiments were carried out to study which soil physical factors, if any, would restrict germina... more Experiments were carried out to study which soil physical factors, if any, would restrict germination and emergence of sorghum (Sorghum bicolor (L.) Moench.) and cowpea (Vigna unguiculata (L.) Walp.), under field conditions in Tanzania. The study also aimed to consider the usefulness of mulching as a strategy to overcome such problems, and to contribute to the development of a strategy for modelling seedling emergence in seedbeds in the field.

Soil and Tillage Research, 2004

ABSTRACT

Land Degradation & Development, 2005

Land degradation has been identified as a serious problem in Tanzania since the 1920s. Among the ... more Land degradation has been identified as a serious problem in Tanzania since the 1920s. Among the factors normally cited as contributing to land degradation are deforestation, overgrazing and inappropriate farming practices. Several attempts by the government to arrest the problem have been based on top-down approaches. Indigenous-based interventions are among the alternative practices adopted by the Soil Conservation and Agroforestry Project in Arumeru District, Tanzania. The main objective of this study was to assess the impact of the indigenous-based interventions on land conservation. More specifically the study intended to assess farmers' perception of land degradation, the adoption rate of indigenous-based interventions, the impact of those interventions, and lastly the sustainability of those interventions. Data for the study were collected through Participatory Rural Appraisal (PRA) techniques and a questionnaire survey. The Statistical Package for Social Sciences (SPSS 1 ) was used to analyse quantitative data and Content and Structural-Functional Analyses were used for qualitative data. The study found that the rate of land degradation was perceived by respondents to be rather severe. The study also revealed that indigenous-based interventions, which require minimal labour and capital, have been highly adopted by many farmers while labour/capital intensive ones have been taken up by fewer farmers. In general, indigenous-based interventions appear to have eased farm operations and contributed towards increased crop yield, improved soil fertility and increased income. Success in some of the indigenous interventions warrants their wider promotion beyond the project area.

European Journal of Soil Science, 1995

A filter-paper technique that can be used to measure the matric potential of field soil is descri... more A filter-paper technique that can be used to measure the matric potential of field soil is described in detail. When a calibrated batch of filter papers is used, the precision is limited by the variability between individual papers and the limitation of weighing to the nearest mg. The absolute accuracy is also limited by the instruments used for calibration. There was reasonable agreement between batches of the same type of paper, suggesting that our generalized calibration curves can be used for Whatman No. 42 filter papers where accuracy is not paramount.

Animal Feed Science and Technology, 2007

Studies to evaluate the effects of feeding rice straw treated with wood ash extract (WAE) on dry ... more Studies to evaluate the effects of feeding rice straw treated with wood ash extract (WAE) on dry matter (DM) intake, in vivo nutrient digestibility and mineral concentrations in the blood and urine were conducted using 12 Boran steers. The steers were randomly assigned to three treatments consisting of untreated, urea treated and WAE treated rice straws in a completely randomised design to estimate the voluntary DM intake. All animals were supplemented with 2 kg of concentrate. An in vivo digestibility trial was performed and pH and mineral contents determined in the urine and blood samples.

Hydrological Processes, 1987

ABSTRACT

The inclusion of legume crops in cropping systems has been shown to improve soil fertility and pr... more The inclusion of legume crops in cropping systems has been shown to improve soil fertility and productivity, but the adoption rate is low among many smallholder farmers. A study to determine the perceptions of the smallholder farmers on groundnut production, use of inputs and cropping systems was conducted in Chisamba District, Zambia. Using a multi-stage sampling technique, 164 farmers from 20 villages within 11 agricultural camps in two agricultural blocks were randomly chosen for the study. Questionnaires were administered to only smallholder farmers who cultivated groundnuts. Results showed that the cropping systems used by smallholder farmers in Chisamba District were crop rotation (90%), mixed-intercropping (5%) and sole-cropping (5%). Groundnut production was mainly undertaken by female smallholder farmers (71%) on land averaging 1.68 ha. However, there was non-significant relationship between gender of the household head and adoption of cropping system (χ 2 (2) = 1.726; p = 0.414). Fifty-seven percent of the smallholder farmers perceived the groundnut variety Natal Common to be most suitable for the study area (χ 2 (4) = 9.745; p = 0.045). It was concluded that particular traits of varieties affected the perceptions and hence adoption decisions of smallholder farmers in Chisamba District.

Low available phosphorus (P) is one of the major hindrances to crop production in acid soils of w... more Low 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 30ml of KH 2 PO 4 in 0.01 M CaCl 2 , containing 0, 80, 150 and 300 µg ml -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 Al 3+ (>2 cmol Al kg -1 ), Al saturation of (> 20% Al) and

American Journal of Experimental Agriculture, 2015

The study was conducted to evaluate effects of conservational tillage on vegetable production on ... more The study was conducted to evaluate effects of conservational tillage on vegetable production on the north-eastern part of Uluguru Mountains in Tanzania. Six treatments such as control conservational tillage; conservational tillage with manure; conservational tillage with insitu composting; control traditional tillage; traditional terrace with manure and traditional tillage with in situ composting were examined. Nutrient levels were determined from soil before and after harvest and from plant samples after harvest. Soil losses were assessed by collecting runoff using polyethylene troughs for each treatment. Analysis of variance and Multiple range test (P=0.05) was done to test the effect of the treatments. The differences (P=0.05) on soil loss, plant nutrient status and vegetable yield were observed. All conservational treatments gave high fresh yield (4.3 - 44.7 ton/ha), high nutrient retention (N% 0.11 - 0.14, P% 5.17 - 16.33, K% 0.33 - 0.36) and experienced low soil losses (0.49,...

Groundwater first started to be used as a source of water supply for the Dar-es- Salaam City in 1... more Groundwater first started to be used as a source of water supply for the Dar-es- Salaam City in 1943. However, many of the existing boreholes in Dar-es-Salaam were drilled in 1997 after Tanzania experienced a severe drought; since then groundwater use in the city shows an increasing trend and currently over 50 percent of residents in Dar es Salaam City relies on groundwater supply. Today, there are more than 10000 boreholes for domestic, water supply and industrial purposes. Demand and reliance on groundwater from a growing population along the coast raises the need to increase efforts to protect and manage the resource. In the coastal aquifer of Dar-es-Salaam, groundwater quality is influenced by various potential sources of salinity that determine the composition of water extracted from wells. The results show that the origin of salinity in the area is strongly influenced by: groundwater ascending from deep marine Miocene Spatangid Shales through faults, saltwater intrusion on the...

International Journal of Plant & Soil Science, 2015

Among the various soil erosion processes threatening sustainable agriculture, soil losses due to ... more Among the various soil erosion processes threatening sustainable agriculture, soil losses due to root, tuber and bulb harvesting are poorly documented, particularly in tropical environments. A study was thus conducted in two villages with contrasting agro-ecological conditions on Acrisols and Fluvisols in Western Usambara Mountains, Tanzania. The aim was to investigate the mass of soil and nutrients lost and the factors influencing variation of soil loss due to crop harvesting (SLCH) for Carrot (Daucus carrota), Onion (Allium cepa L.) and Potato (Solanum tuberosum L.) Mwango et al.; IJPSS, 4(1): 18-28, 2015; Article no. IJPSS.2015.002 19 under low input agriculture. A total of 108 farm plots were sampled from the two villages. The mean SLCH values were significantly higher for carrot (7.1 Mg/ha/harvest) than for onion (3.8 Mg/ha/harvest) than for potatoes (0.7 Mg/ha/harvest). Soil nutrient losses in kg/ha/harvest were higher for carrot than for onion and potatoes (e.g. 30 N, 0.1 P, 1.5 K for carrot vs 6.3 N, 0.04 P, 0.2 K for onion) in Majulai village. SLCH was greater in Migambo (humid cold) than in Majulai (dry warm) for all the studied crops. Soil water content at harvest time played a significant (P = .05) role in inducing SLCH for onion while bulk density for carrot, whereas for potato they were not significantly influenced by soil water content and bulk density. Soil texture played only a minor role to SLCH of the studied crops. The observed soil and nutrient losses in the current study are substantial and pose a challenge that calls for immediate attention to the harvesting practices in the study area. However, combating water erosion is far more urgent.

Land Degradation & Development, 2014

ABSTRACT Soil erosion is a major threat to food security in rural areas of Africa. Field experime... more ABSTRACT Soil erosion is a major threat to food security in rural areas of Africa. Field experiments were conducted from 2011 – 2014 in Majulai and Migambo villages with contrasting climatic conditions in Usambara Mountains, Tanzania. The aim was to investigate the effectiveness of mulching in reducing soil erosion and restoring soil fertility for productivity of maize (Zea mays) and beans (Phaseolus vulgaris) under miraba, a unique indigenous soil conservation measure in the area. Soil loss was significantly higher (p < 0.05) under miraba sole than under miraba with mulching e.g. 35 vs 20 and 13 vs 8 Mg ha-1 year-1 for Majulai and Migambo villages, respectively, in 2012. Soil fertility status was significantly higher (p < 0.05) under miraba with Tughutu mulching than under miraba sole e.g. 0.35 vs 0.25 % total N, 37 vs 22 mg kg-1 P and 0.6 vs 0.2 cmol (+) kg-1 K for Majulai village; 0.46 vs 0.38 total N, 17.2 vs 10.2 mg kg-1 P and 0.50 vs 0.2 cmol (+) kg-1 K for Migambo village. Maize and bean yields (Mg ha-1) were significantly higher (p < 0.05) under miraba with Tughutu mulching than under miraba sole, 2.0 vs 1.3 for maize and 0.9 vs 0.8 for beans in Majulai; 3.8 vs 2.6 for maize and 1.0 vs 0.8 for beans in Migambo village in 2012. This implies that Tughutu mulching is more effective in improving crop yield than Tithonia, though both could potentially protect the arable land from degradation caused by water erosion under miraba. This article is protected by copyright. All rights reserved.

International Journal of Plant & Soil Science, 2014

ABSTRACT Plant roots may have a strong erosion-reducing effect. However, little is known about ro... more ABSTRACT Plant roots may have a strong erosion-reducing effect. However, little is known about root characteristics of tropical plants used for erosion control. A study was thus conducted in the Western Usambara Mountains, Tanzania to investigate rooting characteristics of Guatemala grass (Tripsacum andersonii), Napier grass (Pennisetum purpureum) and Tithonia shrub (Tithonia diversifolia), also referred to as wild sunflower, and to evaluate their potential for erosion control. For each plant species, mean root diameter (D), root density (RD), root length density (RLD) and root area ratio (RAR) were assessed for six plants in each species and relative soil detachment rate (RSD) predicted. Mean RD values in the 0 - 0.4 m soil depth for Majulai village and Migambo village respectively were 50.9 and 58.6 kg/m3 for Guatemala grass, 30.4 and 31.3 kg/m3 for Napier grass and 22.1 and 23.0 kg/m3 for Tithonia shrub. RLD values were 35.9 and 45.0 km/m3 for Guatemala grass, 31.3 and 150.0 km/m3 for Napier grass and 10.5 and 6.4 km/m3 for Tithonia shrub. Predicted RSD values were 4.43*10-12 and 1.20*10-14 for Guatemala grass, 6.10*10-5 and 2.74*10-4 for Napier grass and 4.43*10-3 and 2.24*10-4 for Tithonia shrub in the 0 - 0.4 m soil depth. The results indicate that Guatemala grass has a higher potential to reduce soil erosion rates by concentrated flow as compared to Napier grass or Tithonia shrub in the 0 - 0.4 m soil depth. These findings have implications on the selection and use of appropriate plants for soil erosion control.

Advances in Research, 2015

The Usambara Mountains in Tanzania are severely affected by soil erosion which has led to deterio... more The Usambara Mountains in Tanzania are severely affected by soil erosion which has led to deterioration of soil properties and reduced crop productivity. Indigenous soil erosion control measures such as miraba which are widely practised in the area have yielded little success. Field plot experiments were laid down in Majulai and Migambo villages from 2011 -2014 on typical soils of the

Journal of Agriculture and Ecology Research International, 2015

ABSTRACT Indigenous soil conservation measures such as miraba have been widely used in Usambara M... more ABSTRACT Indigenous soil conservation measures such as miraba have been widely used in Usambara Mountains for controlling soil erosion but with little success. On-farm runoff experiments were set from 2011–2014 on Acrisols in Majulai and Migambo villages with contrasting agro-ecological conditions in the Usambara Mountains, Tanzania. The aim was to investigate the effectiveness of miraba and miraba with various mulching materials in reducing runoff, soil and nutrient losses and improving productivity of maize (Zea mays) and beans (Phaseolus vulgaris). Results show that mean annual runoff coefficients (mm mm-1) ranged from 0.72 for cropland with no soil conservation measure (control) to 0.15 for cropland with miraba and Tithonia (Tithonia diversifolia) mulching in Majulai village and respectively from 0.68 to 0.13 in Migambo village. Soil loss was significantly (P = .05) higher under control than under miraba with either Tughutu (Vernonia myriantha) or Tithonia mulching e. g. 184 vs. 20 in Majulai and 124 vs. 8 Mg ha-1 year-1 in Migambo village in 2012. The Pfactors were significantly (P = .05) higher under miraba sole than under miraba with mulching in Majulai village (0.18 vs. 0.11) and in Migambo village (0.10 vs. 0.05).The annual nutrient losses in kg ha-1yr-1 were significantly (P = .05) higher under control than under miraba with mulching 367 vs. 37 total N, 0.8 vs. 0.1 P and 14 vs. 4 K for Majulai village; 474 vs. 26 total N, 0.7 vs. 0.1 P and 20 vs. 1.2 K for Migambo village in 2012. Maize and bean yields were significantly (P = .05) higher under miraba with Tughutu mulching than under control (e.g. 2.0 vs. 0.7 Mg ha-1 for maize in Majulai in 2012). Thus miraba with Tughutu mulching is more effective in improving crop yields than miraba with Tithonia and miraba sole.

Journal of Scientific Research and Reports, 2015

ABSTRACT Indigenous soil and water conservation (SWC) technologies such as miraba (rectangular gr... more ABSTRACT Indigenous soil and water conservation (SWC) technologies such as miraba (rectangular grass strip bounds that do not necessarily follow contours) and micro ridges have been used widely in the Usambara Mountains, Tanzania. However, their strengths and limitations to crop productivity have not been investigated. This study aimed to determine soil fertility and crop yield variability under miraba, micro ridges and bench terraces as a way to explore and compare these SWC technologies. A survey was carried out in Majulai watershed (with Acrisols as dominant soils) which is highly affected by soil degradation due to water erosion. Composite soil samples were collected from 0 - 30 cm depth in upper, middle and lower segments within bench terraces, micro ridges and miraba at the upper, mid and lower slopes of the watershed. Contents of most soil nutrients (e.g. available P, K+, Ca2+ and Mg2+) and maize grain yields varied significantly (P=.05) between SWC technologies, with the trend: bench terraces > micro ridges >miraba>control (fields with no SWC measures). Similarly under all SWC technologies soil fertility and maize grain yields varied significantly (P=.05) with slope position, showing the trend: lower slopes > mid slopes > upper slopes. Moreover, soil fertility and maize grain yields varied significantly (P=.05) between segments of the studied SWC technologies except for bench terraces. The trends for both soil fertility and maize grain yields were as follows: lower segments > middle segments > upper segments under micro ridges; lower segments > upper segments > middle segments under miraba. These observations call for management strategies and technological adjustments that would reduce pattern and magnitude of spatial variations of soil nutrients and crop yields under miraba and micro ridges for improved crop production in the Usambara Mountains.

International Scholarly Research Notices, 2014

A field study was carried out to evaluate the effects of tillage practices on soil physical prope... more A field study was carried out to evaluate the effects of tillage practices on soil physical properties in Mwala district, Eastern Kenya, during the long rains (LR) and short rains (SR) of 2012/13. The treatments were disc ploughing (DP), disc ploughing and harrowing (DPH), ox-ploughing (OX), subsoiling-ripping (SSR), hand hoeing with tied ridges (HTR), hand hoeing only (H). These were investigated under three cropping systems of sole maize, sole bean, and maize-bean intercrop in a split-plot design with four replications. Soil physical properties were monitored at different weeks after planting (WAP) throughout the growing seasons.

Journal of Agricultural Science, 2014

Soil water conservation through tillage is one of the appropriate ways of addressing soil moistur... more Soil water conservation through tillage is one of the appropriate ways of addressing soil moisture deficit in rainfed agriculture. This study evaluated the effects of tillage practices on soil moisture conservation and crop yields in Mwala District, Eastern Kenya during the long rains (LR) and short rains (SR) of 2012/13. Six tillage systems: Disc plough (MB), Disc plough and harrowing (MBH), Ox-ploughing (OX), Subsoiling -ripping (SR), Hand hoe and Tied Ridges (HTR) and Hand hoe only (H) and, three cropping systems namely, sole maize, sole bean and maize -bean intercrop, were investigated in a split-plot design with four replicates. Data on soil water content was monitored at different weeks after planting and the crop yields at end of each growing season. A three-season average shows that soil water content and crop yields were higher in conventional tillage methods compared to the conservation tillage methods. Long term tillage experiments are thus required at different locations, under various environmental and soil conditions to validate the study findings.

International Journal of Plant & Soil Science, 2015

A soil profile representative of typical soils of Mwala District, Kenya, was dug to study its mor... more A soil profile representative of typical soils of Mwala District, Kenya, was dug to study its morphology, soil physico-chemical characteristics and to classify it using two internationally known soil classification systems. Disturbed and undisturbed soil samples were taken from designated pedogenic horizons for physical and chemical analysis in the laboratory. Soil morphological observations revealed that the pedon is well drained and very deep with dark brown to dark yellowish brown topsoil overlying brown to strong brown sandy clay loam to sandy clay subsoil.

Soil and Tillage Research, 1996

Experiments were carried out to study which soil physical factors, if any, would restrict germina... more Experiments were carried out to study which soil physical factors, if any, would restrict germination and emergence of sorghum (Sorghum bicolor (L.) Moench.) and cowpea (Vigna unguiculata (L.) Walp.), under field conditions in Tanzania. The study also aimed to consider the usefulness of mulching as a strategy to overcome such problems, and to contribute to the development of a strategy for modelling seedling emergence in seedbeds in the field.

Soil and Tillage Research, 2004

ABSTRACT

Land Degradation & Development, 2005

Land degradation has been identified as a serious problem in Tanzania since the 1920s. Among the ... more Land degradation has been identified as a serious problem in Tanzania since the 1920s. Among the factors normally cited as contributing to land degradation are deforestation, overgrazing and inappropriate farming practices. Several attempts by the government to arrest the problem have been based on top-down approaches. Indigenous-based interventions are among the alternative practices adopted by the Soil Conservation and Agroforestry Project in Arumeru District, Tanzania. The main objective of this study was to assess the impact of the indigenous-based interventions on land conservation. More specifically the study intended to assess farmers' perception of land degradation, the adoption rate of indigenous-based interventions, the impact of those interventions, and lastly the sustainability of those interventions. Data for the study were collected through Participatory Rural Appraisal (PRA) techniques and a questionnaire survey. The Statistical Package for Social Sciences (SPSS 1 ) was used to analyse quantitative data and Content and Structural-Functional Analyses were used for qualitative data. The study found that the rate of land degradation was perceived by respondents to be rather severe. The study also revealed that indigenous-based interventions, which require minimal labour and capital, have been highly adopted by many farmers while labour/capital intensive ones have been taken up by fewer farmers. In general, indigenous-based interventions appear to have eased farm operations and contributed towards increased crop yield, improved soil fertility and increased income. Success in some of the indigenous interventions warrants their wider promotion beyond the project area.

European Journal of Soil Science, 1995

A filter-paper technique that can be used to measure the matric potential of field soil is descri... more A filter-paper technique that can be used to measure the matric potential of field soil is described in detail. When a calibrated batch of filter papers is used, the precision is limited by the variability between individual papers and the limitation of weighing to the nearest mg. The absolute accuracy is also limited by the instruments used for calibration. There was reasonable agreement between batches of the same type of paper, suggesting that our generalized calibration curves can be used for Whatman No. 42 filter papers where accuracy is not paramount.

Animal Feed Science and Technology, 2007

Studies to evaluate the effects of feeding rice straw treated with wood ash extract (WAE) on dry ... more Studies to evaluate the effects of feeding rice straw treated with wood ash extract (WAE) on dry matter (DM) intake, in vivo nutrient digestibility and mineral concentrations in the blood and urine were conducted using 12 Boran steers. The steers were randomly assigned to three treatments consisting of untreated, urea treated and WAE treated rice straws in a completely randomised design to estimate the voluntary DM intake. All animals were supplemented with 2 kg of concentrate. An in vivo digestibility trial was performed and pH and mineral contents determined in the urine and blood samples.