Rural Farmers’ Agroforestry Practices In Imo State, Nigeria

Abstract:

The study was conducted to assess rural farmers’ agroforestry practices in Imo State, Nigeria. The population for the study comprised all farmers involved in agroforestry practices in Imo state. Four local government areas (LGAs) were selected out of 27 LGAs in the state using simple random sampling technique. From the four LGAs, two town communities were purposively selected based on their involvement in agroforestry practices giving a total of eight town communities. From each of the eight town communities, four village communities were purposively selected because of their involvement in agroforestry practices making a total of 32 village communities. From the list of agroforestry farmers compiled in each of the village communities by extension agent, five farmers were selected using simple random sampling technique. In all, a total of 160 agroforestry farmers constituted the sample size for the study. Data for the study were collected through interview schedule. Percentage, charts, Mean statistics, Analysis of Variance (ANOVA), Duncan multiple range test and factor analysis were used in analyzing the data. Results showed that the average age of the farmers was 54 years. Majority (56.7%) of the respondents was male and married (73.1%). The average household size of the farmers was 7 persons. Majority (56.9%) of the farmers got their income from sale of farm products and 35.6% of them engage in trading as their secondary occupation. Majority (68.8%) of the farmers belonged to various organization. About 53% of the farmers had contact with extension agents in the last one year and the average extension contact was 2 times. The average size of land used for agroforestry practices was less than one hectare. Majority (96.9%) of the farmers practiced home gardens. There was an increase in the number of farmers involved in agroforestry practices in the last five years (47.5%). Majority (84.4%) of the farmers planted banana in their farm as the major tree component of agroforestry and majority (98.1%) of farmers cultivated yam as the crop components of the agroforestry practice. The average number of trees planted/protected in the homestead and farmstead varies significantly over the years. There was a decline in the average number of trees planted and/or protected both in the homestead and farmstead from the year 2009 to 2013. The result showed that pruning (87.5%) was the major management strategy used by farmers to maintain their trees while majority (98.8%) of respondents practiced agroforestry to improve soil fertility. Major constraints to agroforestry practices were grouped into knowledge constraints, tree growth constraints and market constraints. The major effective strategy for enhancing agroforestry practices was to increase the awareness of agroforestry practice through training and workshop.

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Assessment Of Soil Biological And Physico-Chemical Benefits Of Legume-Cereal Rotation Systems In Derived Savanna Zone Of Nigeria

Abstract:

Green house and field experiments were undertaken in this study. The green house study was done in International Institute of Tropical Agriculture (IITA), Ibadan, green house, while the field experiments were conducted in the Department of Soil Science, University of Nigeria, Teaching and Research Farm and Dominican Centre for Human Resources Development, Moniya-Ibadan Farm in 2008 and 2009 crop years. The green house study was a 2 x 3 x 2 factorial in completely randomized design (CRD), comprising of two crop rotations, three nitrogen levels and two residue management options as factors, replicated thrice to give 36 pots. In the field experiment, the design was a 4 x 2 x 2 factorial in randomized complete block design (RCBD) with four crop rotations, two nitrogen levels and two residue management options as factors and replicated three times making 48 plots. Each year involved two growing periods comprising initial growth of velvet-bean, cowpea, soybean and maize and subsequent residual growth of maize in all the plots. Soil samples at a depth of 0 to 15cm were collected at onset of the experiment and at the end of each rotation cropping for 2 years for determination of soil properties. Green house experiment had 37 samples while field experiment had 97 samples in each location. In addition, maize dry matter and grain yields were collected at the end of each rotation cropping. The difference between the grain yields of legume/cereal and maize/maize rotations divided by the grain yield of maize/maize rotation was used to calculate rotation benefit. The soil properties and maize yields were subjected to analysis of variance (ANOVA) and stepwise regression, significantly different means were separated using Fischer’s least significant difference (f-LSD 0.05). At the end of the green house experiment, velvet-bean/maize rotation significantly (p < 0.05) increased maize yield over continuous maize by 13.59 %, nitrogen (N) benefit accounted for 4.56 % while non-N benefit accounted for 9.03 %. In 2008, in the UNN soil, the values of N (0.107 %), Ca (0.83 cmol/kg), Mg (0.59 cmol/kg), ECEC (2.86 cmol/kg) and SMBP (0.0024 %) were significantly (p < 0.05) higher in the legume rotation systems while pH (4.7) was significantly (p <0.05) higher in continuous maize. In 2009, the values for N (0.07 %), P (15.64 mg/kg), Mg (0.26 cmol/kg), SMBP (0.0007 %), Ksat (27.5 cm/hr) and AS (21.97 %) were significantly (p < 0.05) higher in legume rotations than in continuous maize. Moreso, in 2008, Moniya soils had ECEC (3.22 cmol/kg) and SMBP (0.0016 %) significantly (p < 0.05) higher in legume rotations while in 2009, SMBC (0.026 %), P¬t (44.48 %) and Ksat (25.76 cm/hr) were significantly higher (p < 0.05) in legume rotations. Regression analyses showed that in Moniya, N and TVS contributed 44 % changes in dry matter while N, P and TVS contributed 74 % of the changes in grain yield in 2008. In 2009, SMBC and N contributed 62 % of the changes in dry matter and SMBC, EA and Ksat contributed 61 % of the changes in grain yield. In 2008, N and Mg UNN soil contributed 51 % of the changes in dry matter and 44 % of the changes in grain yield while in 2009, EA, MBC and Ksat contributed 57 % of the changes in dry matter and SMBC, SMBN and Ksat contributed 69 % in grain yield. Comparatively, velvet-bean/maize rotation had highest percentage rotation benefits (255 %) relative to cowpea/maize (25 %) and soybean/maize (43 %) rotations. Non-N benefits had increase in exchangeable K, Mg, available P, MBC and Ksat.

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Economic Analysis Of Soil Conservation Practices Among Crop Farmers In Enugu State, Nigeria

Abstract:

The broad objective of the study was to analyze the economics of soil conservation practices in Enugu State. This study employed multistage random sampling technique for selecting the respondents. First stage involved simple random selection of one local government area from each of the three (3) agricultural zones. Then three (3) farming communities were selected from each of the three selected local government areas. This gave a total of nine (9) communities for the study. Secondly, ten (10) farm households were randomly selected from each of the three farming communities, making a total of ninety (90) farm households. Well structured and pre-tested questionnaire, personal observation and focus group discussion were used for data collection. Data were analyzed using descriptive statistical, multinomial logit model, partial budget and a composite benefit- cost simulation model. The study showed that most of the farmers adopted more than one soil conservation practice. The conservation practices adopted most by the farmers included; animal and green manure application (100% and 85.55% respectively), cover crop planting (70%), construction of erosion control structures (57.77%), multiple cropping (45.55%) and reduced tillage (40%), incorporation of crop residues ( 26.66%), mulching ( 23.33%), crop rotation ( 21.11%), fallowing ( 14.44%), across slope-cultivation (12.22%), planting of perennial grass barriers (11.11%) and vegetation planting (8.88%s). Majority of the farmers were males (75.56%), the mean age of the farmers was forty six years, and about eighty seven percent (87%) of the farmers had a house hold size of six to ten persons. Majority of the farmers (725%) used family labour, and 53.35% of the farm land was individually owned by the farmers. An increase in farm size showed significant (P<0.05) increase in the application of green manure (z = 2.25) and crop rotation (z = 2.08). Similarly, increase in house hold size showed a significant (P<0.05) increase in the construction of erosion control structures with a 2.54 magnitude of the z-value. An increase in farm size and sex showed a significant (P<0.05) increase in the use of crop rotation (z = 2.31 and 2.75 respectively). Sex also showed a significant (P<0.05) on the used of crop residues with a 1.96 magnitude of the z-value. A benefit cost analysis estimated the cost of soil conservation as N 1,462,300 and the benefit of soil conservation as N 3,246,800 with a net profit of N 1,784,500 and a net present value of N 37,167,285. High capital and labour demand (100%), insecure land tenure (98%), high risk and stability of practice (96.7%), poor policy support by government (95.6%), inadequate access to information and extension services (95.6%), poor returns to land, capital and labour (81.1%), perception and values of practices (51.1%) and perceived attributes of an innovation (35.6%), are some of the factors that limited the used of soil conservation practices by farmers in the study area. Granted that soil conservation practices are expensive, the benefits exceed the cost and it is the only option open to the farmers facing degraded farm lands. Owing to the fact that the farmers are poor and cannot meet up with the financial demands of soil conservation, the government should assist them in terms of financial subsidies and soft loans to enable them meet up with the financial challenges of soil conservation. Land ownership policies and property right information should be made available and accessible to the farmers, since most of the farmers are afraid on investing heavily on their family lands.

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Comparison Of The Physicochemial Potential Of Boiler Ash, Poultry Droppings And Inorganic Fertilizer And Their Effects On Ultisol And Maize Performance In South Eastern Nigeria

Abstract:

The power boiler ashes (BA) from burnt oil- palm mill wastes at Solive Vegetable Oil Mills Ltd, Nsukka has not been assessed for its crop-use potentials before, and its disposal could pose environmental challenge in future. Several studies have shown that recycling such ash through agronomic production system could alleviate the risks associated with its disposal and make it a value-added input in crop production with the potentials of solving the challenges posed by high cost of mineral fertilizers and low fertility status of soils. The use of this BA can only be sustained if soil quality improvement and increased crop productivity effects can be demonstrated. The extent to which it can improve an Ultisol and increase maize performance relative to commonly used organic manure (poultry droppings) and inorganic fertilizer (N P K fertilizer) is not known. This study compared the crop-use potentials of BA with that of poultry droppings (PM), inorganic fertilizer and their combinations as well as their effects on an Ultisol and maize performance. It also compared the effectiveness of the different levels of BA, PM, and NPK fertilizer and their combinations on soil boron, cadmium and zinc loadings and uptake by maize plant. The study was conducted on an Ultisol at the Research Farm of the Department of Soil Science, University of Nigeria, Nsukka. The experiment was laid out in a randomized complete block design with three replications. The treatments were a control (no amendment), and a sole application of three levels of BA (10, 50, and 100 t ha-1) designated BA10, BA50 and BA100, respectively; three levels of PM (5, 10, and 20 t ha-1) designated PM5, PM10 and PM20 , respectively; three levels of NPK 20-10-10 fertilizer (75, 150, 300kg ha-1) designated NPK75, NPK150 and NPK300, respectively. In addition, combinations of different levels of BA with different levels of each of PM and NPK fertilizer (BA100+PM5, BA50+PM10, BA10+PM20, BA100 +NPK75, BA50 +NPK150 and BA10 +NPK300) were studied. The plots were planted with Oba Super II maize variety and changes in the physicochemical properties of the soil and crop-use potentials of the amendments were monitored for two consecutive years and compared. The physcico-chemical properties of the BA, PM and soil were determined pre and post experiment. Maize grain yield parameters were measured. Data collected were subjected to one-way analysis of variance and significant treatment means were separated by Fisher’s least significant difference at 5% level of probability. The BA consisted mostly of sand-sized particles (741 g kg-1), and had low bulk density (0.37 Mgm-3), high saturation moisture content (77%), high pH (8.9) and high electrical conductivity (441 d S cm-1). The contents of organic carbon was high (12.5 mg kg-1), nitrogen very low (0.24 mg kg-1) content, phosphorus high (298.5 mg kg-1) and K high (9.58 cmolkg-1) while, Fe, B, Cd and Pb values were relatively low. The PM had a higher bulk density (0.49 Mg m-3), N (4.15 mg kg-1) and Fe (167.0 mg kg-1) but lower in P (8.32 mg kg-1) than BA. The NPK plant nutrient ratios of the BA, PM and NPK mineral fertilizer were 1-147-5, 25-5-1, 20-10-10, respectively. Application of ≥ 50 t ha-1 BA increased significantly the sand–sized particles resulting in pseudo-change of soil texture from sandy clay loam to sandy loam. The bulk density of the control soil (1.92 Mg m-3) was significantly reduced to 1.76, 1.03 and 0.88 Mgm-3 in NPK300, BA100 and BA100+PM5 treated plots, respectively. Total porosity (61%) and water holding capacity (54%) were highest in the BA100 treated plots. The BA50 + NPK150 treated plots had the highest mean weight diameter of 0.69 and 0.76 at first and second cropping seasons respectively. The BA100 + NPK75 treated plots had the highest saturated hydraulic conductivity (141cm-3 hr-1) at the second cropping season. The highest soil pH value (7.7) was obtained in plots treated with BA50 and BA10+PM20. The BA100 + PM5 plots had the highest soil N (0.16 mg kg-1 ) and residual available P (124.6 mg kg-1). The highest soil exchangeable K (0.56 cmolkg-1) and Mg (17.8 cmolkg-1) were obtained from BA100+NPK75 treated plots. The NPK300 treated soil had the highest concentration of boron (4.56 mg kg-1) and sodium adsorption ratio (0.37) whereas Cd concentration (0.8mg kg-1) was highest in BA50 treated plots. The BA100 treated plots had the highest Mn concentration of 11.6 mg kg-1 and Zn (12.04 mg kg -1). Application of BA100 impeded maize germination (21%) but its residual effect on germination was highest (83%). The dry shoot biomass at 12 weeks after planting (WAP) was highest (421 g plant-1) in BA50 + PM10 treated plots. Application of BA10 + PM20 produced tallest maize plants (89.5 cm plant-1), highest leaf area index (7.32) and had the maximum maize grain yield of 5.43 tha-1 at the first cropping season; while, PM20 produced the highest residual effect (2.56 tha-1). The nitrogen (2.3 mg kg-1) and potassium (96.1 mg kg-1) concentrations in maize grain from plots treated with BA100 and BA100 + NPK75, respectively, were the highest. Residual effect of PM5 produced grains with the highest P content (0.82 mg kg-1). The boron (14.5 mg kg-1) and Cd (4.53 mg kg-1) concentrations were highest in maize grains grown in BA100 + NPK75 and BA50 + PM10 treated plots, respectively. The bio - concentration factor of the heavy metals in maize grains as affected by the amendments were in the order B > Zn > Cd while their residual effects were Cd > Zn > B. The result revealed that BA when compared with other alternatives (PM and NPK fertilizer) was superior in soil conditioning but poor as a source of plant nutrient. Therefore, BA should not be applied alone without supplementary nutrient source especially when used for crop production. It is also preferable to blend it with organic manures like poultry droppings rather than inorganic manure such as NPK.

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Soil Dispersion And Hydraulic Conductivity In Relation To Clay Content, Exchangeable Sodium Percentage And Electrolyte Concentration In Soils Of Southeastern Nigeria

Abstract:

The objective of the study was to investigate the influence of some soil properties on dispersion and hydraulic conductivity of soils. Twenty soil samples collected from a depth of 0-20 cm were analyzed for their physical and chemical properties. The total clay fraction (clay) of the particle size distribution ranged from 80 to 380 g/kg with a mean of 203 g/kg and a coefficient of variation (CV %) of 47.5%. Total silt was between 20 and 400 g/kg with a mean of 129g/kg and a CV of 86.9%. Water-dispersible clay (WDC) varied from 60 to 160 g/kg, with an average WDC value of 95.5g/kg and a CV of 30.1%. The values of water-dispersible silt (WDSi) ranged between 10 and 380 g/kg with a mean value of 101g/kg and a coefficient of variation of 109.7%. The electrical conductivity of the soils ranged from 16 to 22 μS/cm with a mean of 17.95 μS/cm and a coefficient of variation (CV %) of 9.30%. The exchangeable sodium percentage (ESP) of the soils varied from 0.43 to 2.76% with a mean of 1.1% and CV of 46.36%. The soil organic carbon content of the soils ranged from 0.8g/kg to 27.2g/kg. Total nitrogen content of the soils ranged from 1.0 to 3.4g/kg with a mean of 2.4g/kg and a coefficient of variation (CV %) of 20.83%. The clay dispersion ratio (CDR) of the soils varied between 0.16 and 0.92 with an average CDR of 0.58 and 46.6% coefficient of variation (CV). The total clay content (clay) had highly significant negative correlations with dispersion ratio (DR), clay dispersion ratio (CDR) and clay dispersion index (CDI) ‘r’ = - 0.84**, - 0.91** and - 0.91** respectively, but positively, it had highly significant correlations with clay flocculation index (CFI) and aggregated silt and clay (ASC) ‘r’ = 0.91** and 0.96** respectively. The total clay content correlated negatively and significantly with exchangeable sodium percentage (ESP) ‘r' = - 0.49*. Exchangeable sodium percentage had significant and positive correlations with exchangeable sodium (Na+), electrical conductivity (EC) and bulk density (BD) (r = 0.52*, 0.48* and 0.46* respectively). Soil organic carbon (SOC) correlated positively and significantly with hydraulic conductivity (Ksat) ‘r’ = 0.54*. Dispersion ratio (DR) positively and highly significantly correlated with CDR and CDI (r = 0.86** and 0.87**) respectively but negatively and highly significantly, it correlated with CFI and ASC (r = -0.87** and -0.93**). Clay dispersion ratio (CDR) had a positive and highly significant correlation with CDI (r = 0.99**). Water- dispersible clay (WDC) had a negative and significant correlation with BD (r = -0.53*). Water-dispersible silt (WDSi) also had a negative and significant correlation with BD (r = -0.54*). Dispersion ratio (DR) had positive and significant correlations with pH both in water and in KCl (r = 0.46* and 0.56*) respectively. The clay contents had positive and highly significant correlations with the levels of dispersion in all the soils. As the amount of 0.1N NaOH used for dispersion increased, the amount of dispersed clay increased while hydraulic conductivity of the soils decreased correspondingly.

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Evaluating the Effectiveness of Four Selected Methods of Investigating Soil Erosion Effect on Soil Productivity in Nsukka, Enugu State, Nigeria

Abstract:

This study was conducted in 2012 at the University of Nigeria, Nsukka Teaching and Research Farm (UNN), and Ekwegbe, both in Nsukka agricultural zone; to evaluate the effectiveness of four selected methods of quantifying erosion effect on soil productivity at Nsukka, southeastern Nigeria. The four methods were (1) desurfacing technique (DT), (2) Neill’s (1983) productivity index, (3) modified productivity index (MPI) and (4) Riquier’s productivity index (RI). Soils were sampled at 0-30, 30-60, and 60-90 cm depth zones at each location prior to planting and after harvest. Incremental depths (0, 2, and 4 cm) of topsoil layers were manually removed to simulate erosion at the two sites. Poultry manure (10 t ha-1) was applied two weeks before planting as a soil amendment. Correlation and regression analyses revealed that RI was significantly (p < 0.05) correlated (positively) with plant height at 10 WAP (r = 0.75*), LAI at 14 WAP (r = 0.76*) and pod yield (r = 0.72*) at UNN, and was ranked first in effectiveness, followed by DT, which had a significant (p < 0.05) negative correlation with plant height at 6 WAP (r = -0.45*), while PI and MPI were less effective. At Ekwegbe, DT showed significant (p < 0.05; p < 0.01) negative correlations with plant height at 10 (r = -0.42*) and 14 WAP (r = -0.66**), and LAI at 14 WAP (r = -0.52**), and was validated as the most effective index, whereas RI, PI and MPI were less useful. Based on RI, the soils at UNN and Ekwegbe had productivity index ratings of 15% and 8%, respectively, placing them in the productivity class IV (poor productivity). Following the application of poultry manure and tillage, the soils recorded potentiality index ratings of 22% and 13%, respectively, raising the potentiality class of the UNN sandy clay loam soil to III (average potentiality), while the Ekwegbe sandy loam soil remained in class IV (poor potentiality). The computed coefficients of improvement (Ci) were respectively 1.5 and 1.6 for the soils at UNN and Ekwegbe. The findings indicated that although the current productivity levels of the soils were poor, there was room for improvement, given necessary management practices.

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Characterization and Identification of Contemporary Diagnostic (B) Horizons of Soils in Ideato North Local Government Area of Imo State, Southeastern Nigeria

Abstract:

There is a dearth of scientific information on the soils of Ideato North Local Government Area of Imo State in Southeastern Nigeria. This study was carried out to characterize and classify these soils with special emphasis on the identification of diagnostic B- horizons present in them. Free survey method was employed to locate the representative profiles. Ten profile pits were dug, properly studied macromorphologically, georeferenced using handheld Global Positioning System (GPS) Receiver and sampled based on the identified horizons. Another set of samples at 10 cm intervals from top to bottom were collected. A total of 491 samples were collected. 56 soil samples and 54 core samples were collected from the identified horizons, while 195 soil samples and 186 core samples were collected from the 10 cm interval sampling and these were analyzed for chemical and physical properties. Results were presented using descriptive statistics. Two major parent materials in the area were identified as Shales and Sandstones. Results show that the soil texture classes consist of sand, loamy sand, sandy loam and sandy clay loam. However the dominant soil textures in most of the profiles were loamy sand which mostly occurred in the subsurface layer. Profiles 1-7 of soils investigated were well- drained, while profiles 8, 9 and 10 were poorly drained. Most of the soil colours consist of Hues of 2.5YR, 5YR and 7.5YR except for profiles- SE/IM/IDN/ ARO 1 – 008 and SE/IM/IDN/ ARO 2 – 009 that have varying Hues of 5Y, 10YR, 5GY and 2.5Y. Soil bulk density was low to high ranging from 1.23g/cm3 to 1.94g/cm3. Soil pH values ranged from extremely acidic (pH 4.4) to slightly acidic (pH 6.1). The values of exchangeable calcium and magnesium are low to high, ranging from 0.20 cmol/kg to 6.20 cmol/kg for calcium and from trace to 30.20 cmol/kg for magnesium while the values of sodium and potassium are very low ranging from 0.005 to 0.052 cmol/kg for sodium and from 0.003 cmol/kg to 0.016 cmol kg-1. The cation exchange capacity (CEC) is low to high ranging from 5.20 cmol kg-1 to 51.20 cmol kg-1. The exchangeable acidity is trace to low, the soil organic matter is low to high ranging from 0.07 g/kg to 5.00 g/kg with the high values occurring on the epipedons. The values of percentage base saturation (PBS) of the representative profiles are low to very high ranging from 2.32% to 82.20%. The values of effective cation exchange capacity (ECEC) are low (1.457 cmol kg-1) to high (35.56 cmol kg-1). The available phosphorus is low ranging from 0.004 cmol/kg to 0.013 cmol/kg. The values of Water Dispersible Clay (WDC) range from 4.32% - 20.32%. The diagnostic criteria such as clay coatings/cutans, subsurface to surface clay ratio of 1.2, lithologic discontinuity, abrupt textural changes, artifacts, CEC. ECEC, etc. were identified. The two diagnostic B- horizons identified in the study area are Kandic horizon and Argillic horizon (USDA) which are similar to Argic horizon (FAO/UNESCO (WRB). The soil profiles were classified according to the nomenclature of Soil Taxonomy (ST) and correlated with FAO/UNESCO(WRB) as follows: USDA are: Kandic, Arenic Rhodic Kandiudults, [Urualla]; Kandic, Arenic Rhodic Kandiudults [Isiokpo]; Kandic, Rhodic Kandiudults [Akpulu]; Kandic, Arenic Rhodic Kandiudults [Akokwa]; Kandic, Arenic Kandiudults [Osina]; Kandic, Arenic Kandiudults [Uzii]; Argillic, Rhodic Paleudults [Obodoukwu]; Argillic, Arenic Oxyaquic Hapludalfs [Arondizuogu I (wetland)]; Argillic, Typic Hapludalfs [Arondizuogu II] and Argillic, Typic Paleudults [Umualaoma]. The corresponding nomenclatures arising from classification of the soils by FAOUNESCO (WRB) are: Rhodic Acrisols (Arenic) [Urualla]; Rhodic Acrisols (Arenic) [Isiokpo]; Rhodic Acrisol [Akpulu]; Rhodic Acrisols (Arenic) [Akokwa]; Haplic Acrisols (Arenic) [Osina]; Haplic Acrisols (Arenic) [Uzii]; Rhodic Acrisols (Cutanic/Differentic) [Obodoukwu]; Gleyic Lixisols (Cutanic/Arenic) [Arondizuogu I (wetland)]; Abruptic Lixisols (Cutanic) [Arondizuogu II] and Leptic (Abruptic) Lixisols (Cutanic) [Umualaoma].

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Effects of Sawah Water Management Systems on Soil Properties and Rice Grain Yield in Ebonyi State Southeastern Nigeria

Abstract:

In an attempt to replicate the successful Japanese Satoyama watershed management model in the African agro-ecosystems, sawah rice cultivation technology has been introduced to West Africa in the last two decades. This study was conducted in inland valley at two different locations (Akaeze and Ikwo), to evaluate the effects of sawah water management systems on soil properties and rice grain yield. A split-split-plot in a randomized complete block design was used to evaluate these three factors (sawah types, growing environments and soil amendments) as they affect the soil properties of these two locations and the grain yield of rice as a test crop. Three sawah types and four rice growing environments were used in each of the two locations and they included; rain-fed sawah, spring type and pump type. The rice growing environments are; complete sawah- bunded, puddled and leveled rice field (CS); farmers environment- no bunding and leveling rice field (FE); incomplete sawah- bundding with minimum leveling and puddling rice field (ICS) and partial sawah- after bunding, no puddling and leveling rice field (PS). There were five levels of manure application, which were replicated three times and these included; rice husk at 10 ton/ha; rice husk ash at 10 ton/ha; poultry droppings at 10 ton/ha; N. P. K. 20: 10: 10 at 400kg/ha and the control (Zero application). The study was undertaken in 3 cropping seasons (2008, 2009 and 2010) using the same watershed and treatments. The treatments were applied annually, but the effects of additive residual effects of the amendments were not studied in the course of this research. At the end of each harvest, the soil physical properties analyzed for included; soil BD, total porosity, water stable aggregates, mean weight diameter, water retention and saturated hydraulic conductivity. While that of soil chemical properties included; soil pH, OC, total nitrogen, exchangeable bases (Na+, Ca2+, Mg2+ and K+). Others included CEC, exchangeable acidity, base saturation and available phosphorous, while the rice grain yields was measured. The results showed that the soil pH, organic carbon (OC) and total nitrogen (TN) were significantly improved by sawah types in all the studied soils. At Akaeze pH measured in water varied from 3.8 to 3.9, 4.3 to 4.5 and 4.5 to 4.6 in the first, second and third year (rain-fed to spring sawah type), respectively. The Ikwo soil showed pH mean values of 3.6 to 3.7, 4.4 to 4.6 and 4.6 to 4.8 in the 1st, 2nd and 3rd year of planting, ranging from rain-fed to spring sawah type, respectively. These parameters (pH, OC and TN) were also improved statistically upon by the different growing environments in different ways. The pH at Akaeze varied from 3.9 to 4.0, 4.2 to 4.4 and 4.5 to 4.8 in 1, 2 and 3rd year of study, ranging from farmers’ to complete sawah growing environment. The pH changed from 3.5 to 3.7, 4.3 to 4.6 and 4.5 to 4.9 within the three years of study and from farmers’ to complete sawah growing environment in Ikwo location. Also, the amendments equally positively influenced these parameters in the two locations. The SOC values in Akaeze location ranged from 1.05 to 1.14% (pumping to rain-fed) in the first year, 1.09 to 1.26% (pumping to spring sawah type) in the second year and 1.10 to 1.27% (pumping to spring sawah type) in the third year. In Ikwo location it ranged from 0.84 to 1.02% in the first year, 0.91 to 1.10% and 0.94 to 1.14% in the second and third year from rain-fed to spring sawah type, respectively. The exchangeable bases were also positively statistically influenced by these three factors tested and their interactions in both locations in most years of study. The results indicated that the CEC was positively improved by sawah types, growing environments and amendments in different forms in second and third years of study in both locations. The range values for growing environments in Akaeze varied positively (P<0.05) from 5.60 to6.31 cmolkg-1 for the 1st year, 5.44 to 10.70 cmolkg-1 (farmers’ to complete sawah environment), and 5.52 to 9.34 cmolkg-1 (farmers’ to complete sawah growing environment), in the 2nd and 3rd year, respectively. The mean values Ikwo location ranged from 9.56 to 10.89 cmolkg-1 in the 1st year, 10.17 to 12.73 cmolkg-1 and 10.61 to 13.24 cmolkg-1, in the 2nd and 3rd year, respectively. The results showed that poultry droppings significantly improved the CEC higher within the periods under study in the two locations. The mean values of CEC in Akaeze varied from 4.18 to 6.83 cmolkg-1, 3.92 to 10.86 cmolkg-1 and 3.78 to 9.15 cmolkg-1, in the 1st, 2nd and 3rd year of study. The mean values of CEC for the periods under study ranged from 7.36 to 11.27 cmolkg-1, 7.64 to 13.09 cmolkg-1 and 7.85 to 13.74 cmolkg-1 for the 1st, 2nd and 3rd year. The EA was also significantly reduced by these factors in both second and third years of study in Akaeze, whereas in Ikwo location, the soil EA was positively statistically reduced by these factors for the three years of study. The EA on the 3rd year varied from 2.39 to 2.99 cmolkg-1, (complete to farmers’ growing environment) in Ikwo soils, while in Akaeze, it varied from 2.99 to 3.07 cmolkg-1, (partial to complete growing sawah growing environment) on the same 3rd year of study. The available phosphorous was significantly improved by these three factors and their various interaction forms in both second and third year of study in the two locations. In the same manner, the base saturation was affected in most years of study by the studied factors and their various forms of interactions. The soil bulk density (BD) was significantly reduced differently by sawah types; growing environments and soil amendments in both sites in the three years of study. It was observed that the interactions of sawah types and growing environments; sawah types, growing environments and amendments did positively (P<0.05) reduced the soil BD of Ikwo soils for the second and third year period of study, while in Akaeze site, it was the interaction of sawah types and growing environments only that did positively reduce the soil BD in the first and second year of study. The total porosity was also improved in the same periods of study in both locations by the studied three factors and their interactions. The water stable aggregate (WSA), water retention (WR) and saturated hydraulic conductivity (Ksat) were also significantly improved upon in different forms by the three factors and their various forms of interactions. The effects of sawah water types was observed to have significantly (P<0.05) improved the rice grain yield. The mean grain yield values in Akaeze ranged from 2.87 – 3.54 t/ha, in the first year, 3.63 – 4.03 t/ha in the second year and 4.23- 5.00 t/ha in the third year of planting. The mean grain yield values in Ikwo varied positively (P<0.05) from 3.38 – 3.73 t/ha in the first year, 5.12 – 5.67 t/ha in the second year and 5.39 – 6.28 t/ha in the third year of planting with the spring sawah type yielding higher. It was also obtained that all the sawah growing environments positively improved the grain yield relatively higher than the farmers’ growing environment. The mean values in Akaeze varied positively (P< 0.05) from 2.55 – 3.92 t/ha, 3.16 – 4.46 t/ha and 4.03 – 5.00 t/ha in the 1st, 2nd and 3rd year of planting, respectively. In Ikwo site, it ranged from 3.19 – 3.84 t/ha, 4.84 – 5.86 t/ha and 5.28 – 5.94 t/ha in the first, second and third year of planting, respectively, with complete giving higher yield in both locations than other environments. It was generally observed that plots amended with poultry dropping significantly (P< 0.05) increased the grain yield in both locations in the whole three years of the study. The results from Akaeze location showed the range mean values of the rice as; 1.71 to 4.04 t/ha in the first year, 1.61 to 4.59 t/ha in the second year and 1.78 to 5.52 t/ha in the third year of planting. Also in Ikwo location, the values varied from 1.87 – 4.12 t/ha, 1.98 – 6.78 t/ha and 2.09 – 6.75 t/ha in the 1st, 2nd and 3rd year of planting, respectively. The combination of sawah management and amendment practices improved the soil properties and rice grain yield significantly (p < 0.05) in most of the years in both locations.

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Mobility of Heavy Metals from the University of Nigeria Sewage-Sludge Disposal Site to the Surrounding Soils and Plants

Abstract:

This study was carried out at the University of Nigeria, Nsukka sewage disposable site. The study was to quantify the mineral contents of sewage sludge and assess their mobility in the soil and plants around UNN disposal site. The experimental layout was a 4x3 factorial in RCBD in which distance from the sewage disposal site and soil depth were the two factors under consideration. The distances from sewage pond were 0 (edge), 100, 300 and 2000 m away from the sewage pond with 2000 m serving as control while soil depths were 0¬¬¬ – 40, 40 – 80, and 80 – 20cm. Soil and plant sampling was carried out from three distances in both sewage site and at the control site. Physico-chemical properties of the soil were determined. Four heavy metals (Cd, Cu, Hg and Pb) were determined from the soil, plant samples as well as the sewage sludge. Results showed that the effects of distance and soil depth were significant (P < 0.05) on pH, exchangeable bases, cation exchange capacity, organic matter, total nitrogen, exchangeable acidity and available phosphorous. At the control site there were no differences among soil properties except organic matter that decreased significantly (P < 0.05) with increase in depth. All the chemical properties determined decreased with increase in depth, except exchangeable acidity which increased with increase in depth. Cadmium, Cu, Hg, and Pb, significantly (P < 0.05) decreased as both distance and depth increased. There was an obvious high heavy metal content in the soil of disposal site when compared with the control soil. In the tissues of the three plants (Manihot spp, Zea mays, Pannicum maximum) studied, Cd, Cu, Hg, Pb concentrations were significantly different (P < 0.05) at 0, 100, 300 and 2000 m distances. Heavy metal content observed in plant tissues at the disposal site was relatively high when compared to that of the control site. Therefore, it follows that the studies at the University of Nigeria Nsukka sewage disposal site results in an increased concentration of soil property, such as organic matter, macro and micro nutrients. The mobility of heavy metals (Cd, Cu, Hg, and Pb) from soil to leaves suggest that all these metals were mobile from soil to plant components. Heavy metal concentrations varied among the tested crop plant, which reflects their differences in their uptake capabilities and their further translocation to the shoot portion of the plant. The bioconcentration factor at both root and leaf tissues of crop plant did not show any abnormal accumulation of heavy metals at sewage site. From the study the heavy metal contents of the sludge, soil and plant species were below toxicity levels when compared to WHO/FAO standards.

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Impact of Solid Minerals Mining on Selected Soil and Water Properties in Enyigba, Ebonyi State, Nigeria

Abstract:

Indiscriminate and uncontrolled mining activities give rise to significant negative environmental impacts such as pollution of water bodies and farm lands, thus leading to decrease in soil fertility and soil quality as well as land degradation and changes in landscape. Therefore, this research was conducted to evaluate the impact of solid minerals mining at the Enyigba Lead-Zinc mining district in Abakaliki L.G.A of Ebonyi State and to document the present state of soil physico-chemical properties and heavy metal status of both soil and surrounding water bodies. The study examined the extent to which heavy metals from mining activities have contaminated the soil as well as the surface waters within the vicinity of mine sites. In the study, two factors were considered: factor A - Soil depths (surface soil: 0-15 cm and subsurface soil: 15-30 cm) and factor B - Distances from mine pits (100 m, 200 m, 300 m, 400 m and 500 m away from mine pit). Four mining sites (Mbaraeke Enyigba, Mkpoda Ugwvu, Nwamgbam Uchakuru and Azu Enyigba) within Enyigba mining vicinity were selected for the study to represent four replications. These were compared alongside a control (located 1.5 km away from Enyigba mining vicinity). Core and auger soil samples were collected and analysed in the laboratory following standard methods. The pH of the mine sites ranged from 5.9 to 6.3. The bulk density value at the subsurface soil of mine area (1.67 g/cm3) was significantly (p < 0.05) higher than the surface soil (1.53 g/cm3) and control (1.59 g/cm3). The values of total porosity in all distances and depths were significant, recording a reverse trend compared to bulk density values. The textural classes at different distances and depths were predominantly sandy clay loam including those of the control. However, higher values of clay were obtained at lower depths (15 – 30 cm) at both mine area and control. Available phosphorus (5.22 mg/kg – 2.98mg/kg), soil organic carbon (1.65 % - 1.15 %) and magnesium (2.67 cmol/kg – 2.21 cmol/kg ) decreased with depths in the mine area. The CEC (15.5 cmol/kg) and percent total nitrogen (0.16 %) of the mine area were lower than the control (20.00 cmol/kg and 0.16 % for CEC and percent total nitrogen respectively). Heavy metal concentrations (Arsenic (As) 0.166 mg/kg, Cadmium (Cd) 20.373 mg/kg, Copper (Cu) 2.042 mg/kg, Lead (Pb) 0.498 mg/kg and Zinc (Zn) 4.769 mg/kg) at the mine area were higher compared to the control (As 0.025 mg/kg, Cd 11.097 mg/kg, Cu 0.702 mg/kg, Pb 0.05 mg/kg and Zn 2.3 mg/kg). The heavy metal levels in Enyigba mine site decreased in the order Cd>Zn>Cu>Pb>As in the surface soil and Cd>Zn>Cu>Pb>As in the subsurface soil. The highest concentrations of heavy metals at mine sites were recorded at 100 m top (0-15 cm) soil with significant reduction in concentration levels as a result of increase in distance. The heavy metal concentrations (As 0.166 mg/kg, Cu 2.042 mg/kg, Pb 0.498 mg/kg and Zn 4.769 mg/kg) at mine area were within the acceptable limits in soil with the exception of cadmium (Cd 11.097 mg/kg). The heavy metal concentrations of the water bodies were all above the WHO standards (As 0.01 mg/l, Cd 0.3 mg/l, Cu 2 mg/l, Pb 0.01 mg/l and Zn 3 mg/l) though insignificant concentrations (below WHO regulatory standard for drinking water) of lead (Pb) was recorded in abandoned mine pit, Akpara Izzi stream and Ebonyi river. The ranking of the distribution of heavy metals in the surface waters is Zn>As>Cd>Cu>Pb. Though the concentrations of these metals in soils with the exception of cadmium were found to be low compared to WHO regulatory limits, contamination of soil with heavy metals even in traces is considered a serious environmental concern as these elements can persist in soil for a long time with chances of increasing their concentrations with time.

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