Agricultural Engineering and Land Planning Collection

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Development of a procedure for determination of sub-models for crop and land management factors for soil loss prediction under Morogoro conditions
(Sokoine University of Agriculture, 1997) Shayo, August Joachim
Sub-models crop, Land management, Soil loss prediction, Morogoro one of the most useful means of ameliorating land degradation through sediment losses is by application of soil prediction models. These associates all sources of information including soil physical characteristic data, long term weather data as well as crop management data into a prescribed categorization effective in conservation. Weather and significantly soil physical characteristic data regional-wise, accumulation on regional basis specific models. The purpose varies this necessitates their so as to develop regional of this study was to develop a procedure for determining crop and land management factor(s) sub-models for soil loss prediction under Morogoro condition. A pascal program was employed in determination of the procedure. The procedure involved calculation of the C (Cover and Management factor) and P (Support practice factor) and then compared the obtained results with desired management factors set for the specified location. Weather data, soil data and crop canopy (%) were considered in determination of effective parameters for soil loss prediction. There between soil loss was a and rainfall intensity, good correlation rainfall amount, canopy cover, all rainfall organic carbon content as well as runoff for events and coefficient ranged from treatments. 0.50 the correlation to 0.99. The correlation coefficient for average runoff and sediment loss was found to be 0.86, 0.95 and 0.99 for cropped, bare plots respectively. The overall coefficient of natural vegetated and correlation for runoff and sediment losses at different storms ranged from 0.83 to 0.98. The correlation coefficient intensity was found to be for soil loss and rainfall 0.64, 0.50 and 0.60 for cropped, natural vegetated and bare plots respectively. It was further revealed that rainfall intensity, rainfall amount, canopy cover, soil organic carbon as well as runoff variables correlated better concluded that with soil losses. The later the parameters mark effects in determining crop and land management factor(s) sub-models. Determination of the relationship existing between soil loss and runoff variables indicated a linear relationship.
Development of crop functions for estimating crop and soil management factors of the universal soil loss equation for soil erosion prediction under Tanzanian conditions
(Sokoine University of Agriculture, 2000) Mgina, Christian Alphonce
One of the appropriate tools for predicting soil erosion in planning for soil conservation measures is by the application of soil erosion predictive equations or models. Although many equations do exist for use in soil erosion prediction, they cannot be directly applied to Tanzanian conditions since their developments were done in conditions different from the ones existing in Tanzania. Therefore, it is increasingly acknowledged that such equations are inapplicable for use in predicting soil erosion for Tanzanian conditions. This study was conducted at SUA farm runoff plots with the aim of developing crop functions, as useful data in estimating the crop and soil management factor, C, of the USEE or its revised version (The RUSLE) for its adaptation for use under Tanzanian conditions. Crop height development and canopy curves for maize and sorghum crops were developed using the data collected during the 1998 season and functions relating crop height and crop canopy cover with yield for a three year period (1994, 1995 and 1998) were developed. All the equations developed gave relatively high coefficients of determination (0.72 - 0.99) which were significant at the 95 % level (a = 0.05). The equations developed show that there exists a relationship between crop canopy cover and crop height with yield for both maize and sorghum crops (equations 4.4 to 4.6). Moreover, there exists a relationship between maximum crop height attained by each crop with die final crop canopy cover (equations 4.8 and 4.9). The predicted seasonal crop and soil management factor, C for 1998 season wasestimated using the sub-factor method. The predicted and measured C factor values for maize crop for the 1998 season were 0.147 and 0.086, respectively. For sorghum crop. the values obtained were 0.158 and 0.100. respectively (Table 4.3). Also, a crop development curve was estimated from the developed functions relating yield and crop growth parameters (canopy cover and crop height) and the average curve which related the crop development ratios to crop growth period ratios. This curve was used to estimate the long term C factor value. From the growth curve, the value of 0.136 was estimated (Table 4.4). This value was reasonable when compared to the estimated C factor values for individual years. This suggests that the method can be used to establish average crop growth curves in terms of height and cover for any given crop yield level useful in predicting the crop and soil management factor, C. However, prediction of the crop and soil management factor, C, is appropriate provided that sufficient data bank is available. Thus, research to collect such information is required if soil loss prediction equations are to be locally applicable for their use for practical soil conservation planning in Tanzania.
Performance of physically based models in designing rain water harvesting crop systems
(Sokoine University of Agriculture, 1996) Kamugisha, Stephen Shubila
Three physically based models were used to simulate the effects of rain water harvesting on Sorghum yield in semi-arid Hombolo, Dodoma, Tanzania over three seasons. The models are Runoff estimation Model (THIRST) Crop Growth Model (PARCH) Soil water availability Model Different components of the. models relevant to rain water harvesting were combined to form a complete model to estimate runoff, soil moisture content and crop yield. Rain water harvesting with storage was simulated by supplying runoff collected and stored in reservoirs as supplementary irrigation water for days when soil moisture content was below the allowable value. The performance of the models was tested by comparison between estimated and measured values using regression analysis. There is a fairly good agreement between observed and simulated runoff for a 10 x 20 m catchment with r: = 0.804. .2 For a 10 x 40 m catchment the correlation between measured and estimated runoff is relatively low with r2 = 0.712.3 The simulated moisture trend is the same when compared to the measured soil moisture with correlation coefficient r2 = 0.607, however the model tends to overpredict the soil moisture content. The trend of simulated sorghum yields direct show relationship of increase in yield due to increase in water quantity and distribution with a correlation coefficient 0.622. r2 the model show. inadequacy in predicting the upper limit of water input and hence the effects of water logging on crop yield. From the study it is recommended that: the runoff sub-model. Should incorporate a subroutine for simulating surface depression storage resulting from the changing surface micro relief. rain intensity files should be provided where possible for more reliable results, and further work should be done on the simplified rainfall disaggregate to develop more reliable results. validation of Raws and Brakensiek (1989) pedo transfer functions for soils of semi-arid areas is required. The soil water balance sub-model of modified to PARCH should be simulate the lateral soil water flows, infiltration and drainage with greater perfection. the PARCH model should develop the ability to simulate the effects of anaerobic in the root zone with greater perfection by either reducing establishment during early growth, or by reducing root uptake of water during later growth stages.
Assessment of soil erosion and loss in soil productivity in Mbinga district: a case study of Mahenge village
(Sokoine University of Agriculture, 2000) Haule, Cosmas Benedict Mabalika
The study was conducted at Mahenge village, Mbinga District, Tanzania. The objective of this study was to investigate the magnitude of soil erosion and its impact on soil productivity. Data on soil loss, evaporation, pan coefficient (kpan), rainfall, soil physical and chemical properties, crop growth and yield, crop coefficient (kc) soil and topographical maps from field investigation and various documents were collected. Erosion hazard assessment was done using the USLE and mapped by ARC INFO and ARC VIEW GIS packages, whilst the "erosion induced loss in soil productivity was evaluated using SEPIM. Soil loss for different periods of crop growth showed significant difference between bare plots and ngolo plots. The same relation was shown between bare plots and bench terraces. ANOVA for crop development showed statistical difference between ngolo and bench terrace, with DMRT indicating ngolo to be superior in performance compared to the later. In addition ngolo had lower reduction in yield with cumulative soil loss than bench terraces. The results from the soil erosion hazard mapping indicated that accelerated soil erosion by water was a serious problem in agricultural land in Mahenge village. In the absence of support practice Dystric Cambisols had higher erosion rates (258.69 t/ha/year) while Ferrallic Cambisols had lowest average erosion rates (63.28 t/ha/year) in the village. However, in general soil loss tended to vary with varying soil credibility, support practice, crop cover and topographic factors. Evaluation of PI and SEPIM models at the experimental site showed that SEPIM had more explanation power than PI although the explanation was highly variable. Analysis of available data using the SEPIM indicated that Haplic Phaeoezem soils had higher production potential (0.80) than other soils. In contrast Haplic Acrisols had the lowest production potential (0.44) mainly due to low soil pH. The simulation results showed that Haplic Phaeozem could lose 24 percent of its production potential after 25 years of continued erosion. On the other hand, Haplic Acrisols improved its production potential by more than 100 percent after 25 years of soil loss. The results showed that reduction in soil productivity due to erosion depended on the properties of the exposed subsoil.
The system of rice intersification (SRI) as a climate change adaptation strategy: a case study of Mkindo area in Morogoro, Tanzania
(Sokoine University of Agriculture, 2013) Kombe, Ebenezer Elia
The System of Rice Intensification (SRI) is one way in which farmers practicing irrigation in rice fanning can cope with the effects of climate change by reducing water used for paddy rice production while increasing the yields. System of rice intensification, developed in Madagascar, is a system approach to increase rice productivity through proper management of fewer inputs such as irrigation water, transplanting protocol, and seeds. Field experiments using SRI techniques were conducted in Mkindo irrigation scheme in Mvomero District during the wet season (March- July 2011) and dry season (September 2011- January 2012). One rice variety TXD 306 (SARO) was planted on plots in a randomized complete block design with five treatments based on SRI technique and conventional method where effects plant spacing (in cm) of 20x20 for T1 and T2, 25x25 for T3, 30x30 for T4, and 40x40 for T5 were evaluated. Parameters such as plant height, root depth, tillerig, biomass and grain yields, irrigation water use, and wetting and drying interval were evaluated and the results were statistically analyzed using GenStat software. Results revealed that highest grain yield was achieved in T3 and T4. The mean grain yield for two seasons for T3 and T4 were 4.76 tons/ha and 4.68 tons/ha, respectively. The grain yield obtained from SRI on Farmer Field School (FFS) trials during the wet season were 6.30 t/ha for T3, 4.93 t/ha for T4, and 3.37 tons/ha for T5. The percentage yield increase of the treatments with respect to the reference T1 from the mean of two seasons obtained was 24.28% in T3 and 22.19% in T4. With respect to water productivity, SRI method registered the highest water productivity of 0.47kg/m3 and 0.46 kg/m3 for T4 and T3 respectively. Statistically at p<0.05, water productivity at T1 was significantly different from all other treatments T2, T3, T4 and T5. Under SRI practice, 62.51%, 63.64%, 64.67%, and 64.07% water saving were noticed for T2, T3, T4 and T5 respectively compared to TI. SRI practice for planting space 25x25 and 30x30 cm, wetting and dryinginterval of three days, and younger seedling (<14days) are recommended as good combination for SRI practice in Mkindo area.
Evaluation of pedo-transfer functions for the estimation of hydraulic properties in some Morogoro soils, Tanzania
(Sokoine University of Agriculture, 2002) Mdemu, Makarius Victor Chogimembe
A study was conducted to evaluate some selected pedotransfer functions (PTFs) for soil water retention (SWR) and saturated hydraulic conductivity (Ks) using soils from Sokoine University of Agriculture (SUA) farm. Laboratory methods were used in analysis of collected samples for soil texture, organic carbon (OC), bulk density (BD), total porosity (p) and SWR characteristics (soil WRC). The Ks values were determined using the double ring and tension infiltrometer methods. Existing PTFs for soil WRC and Ks were selected from the literature for evaluation depending on their usability from the obtained soil data, easiness to apply them and their predictive capacity. Representative soil physical properties (RSPPs) for each soil profile studied were calculated using the ratios of individual soil profile horizons depths divided by the total depth of the soil profile. The RSPPs were used in evaluating PTFs for Ks estimation based on field measured Ks. The pedotransfer functions of Tomasella and Hodnett (1998), and PTFs of Ahuja et al. (1984), Campbell (1985), Vereecken, et al. (1990) and Jabro (1992) for SWR and or Ks were evaluated using obtained soil physical properties. Good estimates of SWR were obtained by Tomasella and Hodnett (1998) PTFs. Estimates of Ks proved unreliable by the evaluated PTFs. Simple linear multiple regression models were developed for SWR and Ks using determined soil physical properties following similar procedures to the evaluated PTFs. This was done for SWR so as to include important soil physical properties such as BD and OC, which were not included in evaluated PTFs. Soil texture, BD and OC contributed significantly (p < 0.05) to the developed regression equations for SWR characteristics at different matric potentials. Retained soil water contents significantly (p < 0.05) correlated to percentage clay, OC and BD in most developed regression equations. Estimates of AWC by the developed regression equation were not good enough compared to other estimated soil WRC. Only representative percentage clay had a significant (p < 0.05) contribution to the developed regression equation for Ks estimation. The correlation coefficient for the developed regression equation was high (r = 0.94). Generally, the Ks values estimated using the developed models matched measured values well with mean differences not significantly different from zero. The root of mean squared differences between measured and estimated SWR and Ks were 0.055 cm3cm'3 and 0.198 mm/h respectively. The developed PTFs for soil WRC and Ks gave good estimates compared to evaluated PTFs. It is recommended that more PTFs for soil hydraulic properties be developed using large soil samples under variable soil conditions for reliable estimations of the properties.
The effects of selected levels of mechanization on small-scale rice production systems: a case study of central Luzon in the Philippines
(Sokoine University of Agriculture, 1983) Kigalu, Julius Malimi
This study was tailored to assess the impact of selected levels of mechanization on crop yields, cropping intensity, labor use and energy utilization in rice production in Central Luzon, Philippines. Labor use was partitioned into labor for land preparation, preharvegt tasks and total post production operations. weeding, other Farm households representing three levels of mechanization, namely fully mechanized (using two wheel (using four-wheel tractors), partially mechanized tractors or power human and animal power), were tillers), and unmechanized (using selected at random from eight villages. Three cropping parentheses): seasons (with number 1979/80 wet season (318), wet season of households planting rice in 1980 dry season (211), and 1980 (302) were investigated. The study uses data obtained from the Consequences of the Small Rice Farm Mechanization (CSRFM) project conducted by the International Rice Research Institute (IRRI). Four of the eight villages contained rainfed farms while the remaining four were irrigated. Patterns documented between using farm mechanization and other three approaches: analysis of variables variance were (ANOVA), analysis of covariance models. ANOVA was (ANACOVA) and production function analysis used to compare variances among different mechanized farms while the ANACOVA models were employed to study variations within different mechanized farms. The production function model investigates the combined effects of was used to several explanatory variables on farm productivity: level of fertilizer used, total labor used, others cash expenses, farm size, and dummy variables mechanization and irrigation. The results revealed a statistical representing level of association of high levels of farm mechanization with high yields intensity, low labor used. per hectare, high cropping high level of fertilizer used. high hired labor expenses and high cash expenses. Irrigation, however, more significant effect on showed a cropping intensity than mechanization. The effect of level of mechanization on energy utilization in rice production was also investigated. mechanized farms had higher output mechanized farms during the Results showed that to input 1979/80 wet and energy ratios 1980 dry partially than fully seasons. reverse was observed during the 1980 wet season. The Fully mechanized farms produced both high rice yields (output) and energy output equivalent of paddy and rice to chemicals and labor hours. Irrigation. The study also accounted for high revealed that energy seed, input in rice production. It was thus concluded that farm mechanization is profitable despite the present high prices of commercial fuel energy.
Relating erosivity factors to soil loss: a case study of Hombolo and Morogoro sites.
(Sokoine University of Agriculture, 1996) Ngalesoni, Gabriel Simon
This study was conducted at Morogoro and Hombolo, as part of the ongoing research under the department of Agricultural Engineering and Land Planning.This report acts as interim findings of the research. Ten run off plots were established, four at Hombolo and the rest at Morogoro. Five erosivity factors were regressed to ascertain the best fit on the soil loss.The plots had different treatments of canopy cover for each of the seven rainstorms recorded during the cropping season. El 30 compound erosivity factor and runoff mination of proved to have 0.92 and 0.69,high coefficients respectively.There deter was a significant difference in soil loss between bare plots and other plots with crop cover.However,the difference in runoff amounts was insignificant.
Performance of centre pivot sprinkler irrigation system: a case study of Ubombo Sugar Estate, Swaziland
(Sokoine University of Agriculture, 2014) Msibi, Sandile Trevor
The centre pivot irrigation system is increasingly becoming popular among farmers around the world on account of the benefits the system can offer compared to other methods. Hence evaluation of system performance with the ultimate aim of attaining greater irrigation efficiency and better manage irrigation is paramount. The study evaluated the performance of centre pivot sprinkler irrigation system and its effect on sugarcane yield at Ubombo Sugar Estate in the Lubombo Region of Swaziland. Four centre pivots (EEL09, NKA21, CAS02 and SMB) were selected from 106 centre pivot machines for purposes of evaluation. Information collected included meteorological data, design parameters, water application uniformity, system operating pressure, tyre pressure, system flow rate, sprinkler nozzle discharge and pressure, crop data and planted area, harvesting programs, pumps and motor specifications, pumping hours, cost of power and actual flow rates. Drive speeds of 15%, 20%, 30% and 40% of the centre pivot systems were examined to determine their significance on system performance parameters on the basis of common field operations. Water and power budgeting systems utilized were assessed to determine adequacy of irrigation water supply and implications on system and crop performance. Irrigation water quality, soil physical and chemical properties, soil infiltration characteristics and soil compaction were also examined to determine their influence on system performance and sugarcane yields. Data analysis was carried out using Microsoft Excel, ETo Calculator, Instat, Statistical Package for Social Sciences (SPSS), ArcGIS and HPen32 software. Results demonstrated that centre pivots were accurately designed and properly installed as they adequately supplied water to meet sugarcane demand of 7.5 mm/day. Performance indicators showed that centre pivots were relatively performing well as uniformity indices (CU and DU) were within acceptable standards, i.e. above the base values of 85% for CU and 75% for DU. Recommendedapplication efficiencies (AELQ and PELQ) were only achieved by CAS02 and SMB centre pivot systems as they were above the minimum of 90%. Speed effect results showed a general decline in CU and DU with an increase in centre pivot speed as opposed to an increase in application efficiency. CU for SMB declined from 88.9% at 15% speed to 86.9% at 40% speed setting. A similar trend was evident for both NKA21 and EEL09.PELQ for SMB increased from 93.1% to 98.0%% and AELQ from 92.6% to 100%. A parallel trend was also observed for NKA21 and EEL09. Analysis of variance for these results showed that the performance indicators were not significantly different (p<0.01) among treatments. This demonstrated the ability of the centre pivot irrigation system to apply water uniformly and efficiently across the field at different speeds. Water and power budgets were not satisfactory in meeting estate crop water demand since they did not capture and consolidate relevant parameters needed to accurately define budgets.Water supply was determined by capacities of irrigation structures used and losses were incurred during periods of low demand. Electricity budgets were based on historical power records which affected overall water supply and caused water stress to the crop. Quality of irrigation water was within acceptable levels and had no negative impact on system, crop and soil. Soil physical and chemical properties indicated that soils were inherently sandy and ideal for sugarcane growth save for shallow profiles with low water holding capacities. Soil compaction as a result of mechanical harvesting was a major cause of significant reduction in soil infiltration rates, water storage capacity and hence runoff. Significantly higher soil compaction values at 0 to 15 cm depth (p<0.0l) were associated with EEL09 centre pivot with an average of 3 210 kPa compared to those of NKA2I at 596 kPa, CAS02 at 447 kPa and SMB at 1 389 kPa. Identical observations were made at 0 to 30 cm depth where higher compaction values were associated with EEL09 and SMB. EEL09, a sandy textured field measured a basic infiltration rate of 6 mm/h as a result of compaction while the other less compact sandy textured fields had infiltration rates greater than 70 mm/h. Yields were variable as EEL09 achieved a low yield of 71 t/ha against 147 t/ha for CAS02, 124.8 t/ha for NKA21 and 106 t/ha for SMB. Findings indicate that centre pivots are performing well although potential system performance and sugarcane yields are constrained by limited water and power supply,pressure variations, clogging of sprinklers, rutting of un-gravelled tracks, soil compaction,low water holding capacities, reduced infiltration rates and game encroaching sugarcane fields. It is therefore recommended that constant system checks, improvement of traction on centre pivot wheels, development of new model for water and power budgets as well as undertaking of extensive research on the effects of mechanical harvesting be done so as to improve centre pivot irrigation system performance and sugarcane yields at Ubombo Sugar Estate.
Auger metering studies for fine prilled URSA
(Sokoine University of Agriculture, 1988) Mwombeki, Francis Fabian
ABSTRACT Tne performance of sheet ana 'wire au6ers was studied for meterin6 prilleu urea fertilizer. First the physical characteristics of prilled urea was established. It was found that the angle of repose and the coefficient of fricition on galvanized steel surface increased with increased moisture content.The opening of the hopper bottom, inclination of hooper walls and modes of agitation were studied for uiiximizing fertilizer flow into the metering chamber. A bottom opening width of jO mm, hopper wall angle of 60 o with the horizontal and a rotary or eliptical agitation modes aere founu to provide optimum flow.Succeeding experiments were conducted to study the rate and consistency of fertilizer metering by sheet and wire auoer unaer varying pitch/diameter ratio,delivery tube in .ination, au6er speed and fertilizer moisture.Rate of fertilizer injection into flooded soils was studied under simuxared field conditions. Assessment was also made of the amount of r.-rti 1 i zer adhering to the augers during metering. A pitch diameter ratio of 1.25 give a maximum found to diecharge. Also, fertilizer discharge increased with greater inclination of the delivery tube and decreased with increasing fertilizer moisture contents.The metering accuracy generally decreased with greater inclination of the delivery tube fertilizer granule size decreased metering accuracy.The experiments, of injecting fertilizer in flooded soils were conducted in a rotating soil bin to simulate actual field conditions.The inclination of the delivery tube along the direction of the bin movement gave a higher injection rate than an inclination against the bin movement. The wire auger exhibited a greater injection capability than the sheet auger and produced higher pressure at the tube opening.This auger also encountered less sticking of fertilizer on the flight than the sheet auger.
The Mechanics of a disc plough
(Sokoine University of Agriculture, 1985) Kiriama,L.L.
ABSTRACT An angle attachment was designed to enable disc axis orientation with the soil bin facility developed at the College.A force prediction model by Godwin et al at Silsoe College was used to predict the magnitude of forces to be expected.- The effect of change in axis angle on draught,- vertical and side forces was studied and the results compared with the prediction. It was found that there.was a significant effect in changing the disc axis angle, The draught and side forces were found to be less at 15° than at 0^ 0° axis angle, angle. The optimum axis angle at 25° sweep was found to be about 15 o ’where the maximum downward vertical force occured. Since the experimental and predicted results did not compare well, an exploration of the force prediction model was suggested.Whilst for global prediction the model seemed alright,it was difficult to make it work for all combinations. Although the model worked well with an 0° axis angle and 90° sweep angle, the edge effect and inclination for the other combinations needed greater definition.
Simulation of water productivity for maize under drip irrigation.
(Sokoine University of Agriculture, 2011) Richard,Festo
Water has become increasingly scarce in most of the countries in the world. To use the available water efficiently in crop production, agricultural water productivity (WP) need to be improved. Drip irrigation systems and deficit irrigation practices are the most efficient methods in improving WP. Availability of soil-water-crop simulation and climatic models can also help in the efforts to improve WP. A study was conducted in Morogoro using CROPWAT model to simulate water productivity of maize under drip irrigation by supplying different water deficits. A completely randomized block design was used with three replications and four treatments. The treatments were Tl, T2, T3 and T4 representing 60, 40, 20, 0 percent deficit of ETC (crop evapo-transpiration) respectively. Biomass accumulation (at 45 DAP and 75 DAP), grain yield and harvest index were determined for each treatment and experimental yield reductions were calculated. The CROPWAT simulation was done for each water deficit level and yield reductions were recorded. A comparison was made between experimental and simulated yield reductions. The mean biomass production between the treatments at 45 DAP were not significant different (P<0.05). At 75 DAP mean biomass production (0.684, 0.728, 1.049, 1.378 kg/m2 for Tl, T2, T3 and T4 respectively) were highly significant different (P<0.05). The mean grain yield between treatments, mean water productivity (1.67, 2.2, 1.78, 1.72 kg/m3 for Tl, T2, T3 and T4 respectively) and harvest index values were significant different (PO.Ol). Experimental and CROPWAT simulated yield reductions were not significant different (P<0.01) at all stages for all the treatments. The CROPWAT model adequately simulated the experimental yield response to water for maize (maize water productivity).
Study on tillage systems and their impacts on land degradation for eastern agro-ecological zone in Tanzania
(Sokoine University of Agriculture, 2011) Mohamedi,Saidi Jambuya
Soil tillage had been identified as a major cause of land degradation and soil erosion in Tanzania resulting in soil infertility and low crop yields. A study was conducted at Mkambalani village, in Mkambalani ward, Mikese division in Morogoro Rural District, Morogoro Region, Tanzania. The study aimed to assess tillage systems and their impacts on land degradation for eastern agro-ecological zone. Five (5) tillage systems were selected for the study. The selected systems were No Tillage (NT), Strip Tillage (ST), Basin Tillage (BT), Tied Ridges (TR) and Conventional Tillage (CT). A plot of size 20 m long with width of 1.8 m was established for each tillage system selected and replicated in three times in the slope of 6° farm. The plots planted with maize crop variety TMV1. At the down slope end of each plot the modified Gerlanch troughs were installed to trap water flow and sediment. The study arranged in CRBD design to help in data analysis. Variables measured including, daily sediment for the rainy days, water runoff, daily rainfall, plant growth and yield and soil physical and chemical properties. The results shows that NT treatments produced high amount of runoff on average in most of rainfall events due presence of few cover in the first year of farming while TR treatment were the least. Significant differences were observed between the NT treatments and CT, TR and BT. It means that in first year of practising NT due to bare soil there was no soil protection from rainfall and water flow hence more water runoff. CT was found to be the biggest collector of sediment than other tillage treatments. Significant changes were observed among CT, NT and TR in collection of sediment. CT treatment produced sediment loss of 23.2ton/ha/season, while the TR produced the least amount of 14.4ton/ha/season. This reflects the extent of the productive soils lost in each year due to tillage. There were no significant differences in crop growth and yield were observed and also in soil physical and chemical properties in the first year of the experiment. Under natural rainfall conditions rainfall amount, intensity and distribution differs greatly and all affect soil properties and crop development, hence the one year trial is not enough to draw appropriate conclusion.
Economic valuation of irrigation water in smallholder farming system in rwanda: the case of Kibaya – Cyunuzi scheme
(Sokoine University of Agriculture, 2012) Urujeni Sandrine
Rwanda is in a current shift of management of state controlled irrigation schemes to farmers through the Irrigation Management Transfer (1MT) programme. However, such water management decisions require conceptually correct and empirically accurate estimates of the economic value of water. This study was carried out to determine the economic value of irrigation water in a smallholder irrigation scheme of Kibaya - Cyunuzi. Data was collected from 110 respondents within the scheme. The data was analyzed using descriptive and quantitative methods. The Residual Computation Method was used to compute the economic value of irrigation water for paddy rice - the main crop cultivated in the scheme. The Contingent Valuation Method was employed to elicit the farmers’ willingness to pay for irrigation water and its related infrastructure. Socio-technical analysis helped to capture the process of water control and management through Water Users Associations. Results showed that the average economic value of water in irrigated paddy was low (5.33 Rwf/m3), mainly due to poor management of water. Water productivity was also low (0.08 kg/m3) due to an insufficient supply of water to the scheme. The CVM analysis showed that on average, the respondents were willing to pay 8000 Rwf per ha per annum for irrigation water. IMT impact assessment showed that WUAs are the realms of interaction for different stakeholders involved in water management. The problems farmers were facing in improving water productivity in the scheme were identified but the solutions require joint effort among the stakeholders. Policy decisions related to water sector investments, allocation and management could be better guided if the key dimensions of water i.e. water availability and use, are properly taken into account in valuation.
Influence of institutional set up on performance of traditional irrigation schemes. a case study of Nyandira wards, Mvomero district, Tanzania.
(Sokoine University of Agriculture, 2016) Sumuni,Philip Mathew
This study was conducted in Nyandira ward, Mvomero District, Tanzania to evaluate the influence of institutional set up on performance of traditional irrigation schemes. The study was envisaged to produce knowledge of institutional framework to guide performance of traditional irrigation schemes on efficient use of water resources. GPS reading to digitise the traditional canal, farmer’s interview, focus group discussion and V- notch weir for canal flow measurements were used for data collection. Out of twelve traditional canals, four canals namely Fuku, Mbakana Kati, Mzinga and Nyamiseta No. I were purposively selected. The data were analysed using descriptive statistics, inferential statistical analysis and content analysis. Results showed that out of 93 interviewed farmers (91.4%) 85 people out of 93 were not aware of the National Water Policy of 2002 whereas only (8.6%) 8 people out 93 were aware of the National Water Policy of 2002. This shows that policies are formed and remain to the management (Decision and Policy makers) while people on the ground who are the actual implemented are not aware of what is going on. The results also showed that the majority of the respondents (93.5%) 87 people out of 93 in the study area were not aware of the Water Resources Management Act of 2009. This implies that the community members do not understand their role in water conservation and management in line with the Water Resources Management Act of 2009. The conveyance efficiency for the four canals, i.e. Fuku, Mbakana Kati, Mzinga and Nyamiseta No. 1 were calculated and found to be 63.05%, 62.74%, 60.89% and 60.5% respectively which is fairly good. But the overall efficiency of 34%, 32%, 33% and 37% for Fuku, Mbakana Kati, Mzinga and Nyamiseta respectively was low due to the fact that canals are unlined.
Assessment of the land use changes due to traditional irrigation activities: the case study of four villages around Ruaha Mbuyuni, Iringa and Morogoro Tanzania
(Sokoine University of Agriculture, 2002) Rugenga Elizabeth
The study on assessment of land use changes due to traditional irrigation activities was conducted in four villages around Ruaha Mbuyuni from June 2000 to June 2001. Three sets of aerial photographs (1955, 1976 and 1999) were used, interpreted on mirror stereoscope and analysed using GIS-ARC/INFO program. The area of each class was' calculated for each data set from which the rate of expansion of irrigated farms was determined. The questionnaire survey was conducted to collect information on the historical changes in natural resources and socio-economic activities responsible for land use changes and analysed using SPSS program. Stratified random sampling was also conducted for soil physical and chemical analyses. By using rating procedures the contribution of soil properties in land use changes was carried out. The results showed that irrigated fields expanded by 2056.8ha and 1528.6ha with expansion rate of 97.94ha/yr and 66.46ha/yr from 1955 to 1976 and 1976 to 1999 respectively. Human population increased from 2886 to 16877people between 1967 and 1998. Irrigation activities have been observed to increase the extent of socio-economic activities like firewood gathering and building. The results for soil analysis indicated that, total nitrogen, available phosphorus and organic matter content was low in all fields and therefore low soil fertility in the area. Exchangeable Na were observed to be high in some fields and having high potential to cause soil salinity and sodicity. Other chemical properties i.e pH values, Ca, Mg and CEC were observed to be within the acceptable range for irrigation activities and crop productivity. The soil physical properties indicated that the bulk density of the soil were within the acceptable range for water infiltration and plant roots penetration. The soil textural class was observed to range from sand loam to sand clay loam for the topsoil and sand to clay for the subsoil. Generally, the results have shown that the pattern of land use changes in the study area were due to irrigation activities taking place in the area which has influenced population growth and socio-economic development.
Use of landsat thematic mapper and ancillary data in assessing potential areas for rainwater harvesting cropping systems
(Sokoine University of Agriculture, 1997) Kweka,Amini Rabi
Rain Water Harvesting (RWH) is a system which can store and redistribute the moisture needed to enhance yields, in areas where rainfall distribution limit dryland crop production. In regions where rainfall is insufficient to produce’ even a minimum crop, water harvesting offers the potential to bring those areas under cultivation. However, in many areas,conventional planning data for selecting prospective sites for RWH cropping system is in most cases not easily available or not up to date. This study assess the possibility of using satellite images to improve and up-date the required data.This study used a nested procedure, combining a coverage of a small sample area by Landsat Thematic Mapper (TM) satellite imagery,conventional photo interpretation and analysis of soil and topographic maps to identify potential areas for RWH cropping system. Computer pattern recognition techniques were used to discriminate soil information from the Landsat Thematic Mapper (TM) satellite data on a sample area. Soil mapping units photo from a conventional soil survey and aerial interpretation were matched to the spectral map for interpretation and classified soil description of the generated classes. Field investigations were done to confirr the results of the sample area which was then extended to
Pricing of irrigation water in a farmers-managed irrigation scheme in Tanzania: a case study of lower Moshi.
(Sokoine University of Agriculture, 1999) Mutabuzi,Lutatina James
A computer program model for pricing irrigation water among beneficiaries, was developed by the use of Turbo Pascal language. The data that was used to test the model was collected from Lower Moshi Farmer-Managed Irrigation System (FMIS) in Northern part of Tanzania as a Case Study area.The aim was to evaluate the costs involved in the process of allocating irrigation water with the objective of developing a computer program model appropriate for pricing irrigation water in FMIS in Tanzania. Allam’s (1987) mathematical model for allocating irrigation water price which was developed in Egypt, was adopted and adapted for the purpose. The results show that the irrigation water prices obtained differ between different blocks within the same system, and also there is significant difference of irrigation water prices between two systems that exist in Lower Moshi Irrigation System (LMIS) i.e Rau and Mabogini. By manual calculations, Mabogini irrigation system’s water price ranges from 8,276 Tshs/ha to 14,972 Tshs/ha; while for Rau system it ranges from 3,896 Tshs/ha to 13,857 Tshs/ha; with their mean values of 11,940 Tshs/ha and 10,538 Tshs/ha respectively.The computer program model produced irrigation water prices ranging from 8,479 Tshs/ha to 15,200 Tshs/ha for Mabogini system; while for Rau system they range from 3,913 Tshs/ha to 13,858 Tshs/ha, with their mean values of 12,151 Tshs/ha and 10,414 Tshs/ha respectively. The mean value was adopted as the system irrigation water price in each system. The farmers’ capacity to pay Irrigation Service Fee (ISF) was also assessed and found to be 154,309 Tshs and 194,309 Tshs for tenant and landowner farmers respectively.The irrigation water pricing computer program model was tested for one cropping season. Therefore, more work is required to test it for the two cropping seasons, and in other FMIS so as to develop universal model. This will make it more universally applicable in Tanzania.
Plant-water status and grain yield of maize (zea mays l) in relation to soil water status at Morogoro, Tanzania.
(Sokoine University of Agriculture, 1987) Rwehumbiza,Filbert Bartazar Rwabulala
Analysis was made of reference crop evapotranspiration (Eto) and rainfall (R) data on a 10-day basis over a 10-year period (1973/74 - 1982/83).On the average, ETo exceeds R during the entire short rain season thus making production of crops other than those tolerant to water stress a risky undertaking.The effects of soil water holding capacity (WHC), cultivars,and water regimes on soil ~ and plant - water status, growth, grain yield and yield components of maize (Zea mays L) were identified.The study was conducted during short rains on two soils (both Ferralsols) one x
Assessing the effectiveness of locally made clay pot as an irrigation device.
(Sokoine University of Agriculture, 2011) Solo, Mahatsindry Randzato
Among traditional irrigation systems, pitcher irrigation is one of the most efficient. Water seeps out of a buried pitcher due to the pressure head gradient across the wall of the pitcher directly into the root zone of the irrigated crop. The pressure gradient results from a positive pressure head inside the pitcher and negative pressure head at the outer surface of the pitcher which is in contact with soil. Pitcher irrigation is a cost effective traditional technique, which is easy for small scale farmers to comprehend with. This study considered the effectiveness of locally made pitchers as a micro-irrigation device using beans and amaranths crops. The experimental design was 2x3 factorial arrangements of treatments in a split plot design. The main-plots were two different initial soil moisture contents i.e. soil moisture content at field capacity (31 %, vol.) and 26 % (vol.). The sub-plots were three different plant densities i.e. 4 plants/pot, 6 plants/pot and 8 plants/pot and were replicated three times giving a total of 18 combination treatments. A positive relationship was found between seepage rate and actual evapotranspiration for all pitchers (R = 0.37) showing a sign of auto-regulative capabilities. Under beans, the pitchers were not effective in water saving in all the combination treatments because of high water loss through deep percolation because of poor pot characterization. However under amaranths the pitchers were effective in optimizing the water applied. The water applied was not statistically different (P < 0.05) for all the treatments. These results show that clay pots had low application efficiency. However the pots can still be used on amaranths, with a plant density of 16 plants/pot and at initial soil moisture content of 26 % (volume).

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