Grain Yield Response of Sorghum (Sorghum bicolor) to Tied Ridges and Planting Methods on Entisols and Vertisols of Alemaya Area, Eastern Ethiopian Highlands

Field experiments were conducted under rain-fed conditions between 1986 and 1995 to investigate the effects of soil and water conservation treatments (tied ridges and planting methods) on the yield of an improved sorghum variety (ETS-2752) grown with and without N and P fertilizers on two major soils of Alemaya area, eastern Ethiopian highlands. The yield responded significantly (P ≤ 0.01) to the treatments both under fertilized and unfertilized conditions of the soils studied. However, the magnitude of the yield response and the relative efficiency of the tied ridges and planting methods varied with soil type, fertilization, and total rainfall and its distribution during the cropping season. Regardless of the type of tied ridge used, furrow planting, specifically, closed end tied ridge planting in furrows gave the highest yield in three of the four sets of experiments. Flat bed planting produced the lowest grain yields on all sets of experiments except under the unfertilized condition of Entisols in which open end planting on ridges produced the lowest sorghum yield. Within the tied ridges, closed end performed better than open end in all except the Vertisols without N and P fertilizers. Compared with the traditional (flat bed) planting method, the highest yield increment of 1361 kg/ha (34.5%) due to tied ridges was obtained on the Entisols with NP followed by 1255 kg/ha (48.5%) on the Alemaya black clay soils (Vertisols) under fertilized condition, indicating that the yield response to water conservation treatments was higher under fertilized than under unfertilized conditions on the two soils. Fertilization increased the yield of sorghum by as high as 1576 kg/ha (69.5%) on Vertisols and by 1468 kg/ha (38.3%) on Entisols both from planting in the furrows of closed end tied ridges. The study also revealed that the yield response was higher in seasons with low or poorly distributed rains and on shallow and coarse textured soils.T he results indicate that in areas with low and erratic rainfall such as the Alemaya area, soil and water conservation is indispensable for increasing crop yield

Soil quality attributes induced by land use changes in the Fincha’a watershed, Nile Basin of western Ethiopia

The success of soil management to maintain soil quality depends on an  understanding of how soils respond to land use and practices over time. As a result, the important soil quality indicators were investigated under two land use systems to provide base line data for future research in the Fincha’a Valley Sugar Estate  (FVSE), within the Nile basin of Western Ethiopia. The evidences provided by this study indicated that land use changes caused changes on soil bulk density (ρb), soil water content, Particle size distribution (sand, silt and clay), soil pH, electrical  conductivity (EC), soil organic matter (SOM), total N, carbon to nitrogen ratio (C:N) and available phosphorous (Av. P). The study revealed that soil organic matter (SOM), sand content and total N decreased with increase in soil depth. While bulk density (ρb), EC and clay content increased with soil depth. Particle size distribution (sand, silt, and clay) varied with land use, soil depth and soil type. Particle size distribution was changed from Sandy clay to clay due to land use change. Bulk density (ρb), EC, soil organic matter (SOM) and C:N varied significantly (P<0.01, P<0.05), respectively, with land use and soil depth. Land use changes caused bulk density (ρb) to be increased. The study indicated that soil pH was higher in irrigated land than the un irrigated land. This attributed to the transportation of soluble cations from the upstream to the downstream irrigated land by water soil erosion. The different soil fertility management practices also contributed to the variation. On the other hands, soil organic matter (SOM) and total N were lower in irrigated land. Relatively, the lower soil organic matter (SOM) and total N contents in irrigated land attributed to the optimum soil moisture content throughout the year that created favorable environmental condition for SOM decomposition. The study also revealed that soil management groups and soil water holding capacity at field capacity and permanent wilting point were affected by irrigation (land use).It was identified more than 50% of the soil quality indicators increased with depth. This might be the influence of irrigation water in accelerating leaching process. The main degradation process overcome the study area was waterlogging and soil  compaction. The irrigation development in the area requires improved drainage  network and proper land management. Therefore, reducing the intensive mechanized tillage practices and use of integrated inorganic and organic fertilizers could  replenish the degraded soil quality for sustainable agricultural production in the study area. It is therefore, suggested that appropriate and integrated land  management options for different land use systems together with identification of soil management groups and water retention characteristic curves are required to sustain agricultural productivity while protecting the environmental degradation.Keywords: Soil Quality Land Use Soil Type Environment Sugarcane Land  Management Fincha’a Valley Western Ethiopia Fertilizer

Integrated Use of Farmyard Manure and NP fertilizers for Maize on Farmers’ Fields

A study was initiated in 1997 to introduce the culture of supplementing low rates of NP fertilizers with farmyard manure (FYM) in the maize based farming system of western Oromia. The treatments were 0/0, 20/20, 40/25 and 60/30 kg N/P ha−1 and 0, 4, 8, and 12 t FYM ha−1 in factorial arrangement in a randomized complete block design with three replications. The experiment was conducted at Laga Kalla, Walda, Shoboka, Harato, and Bako Research Center using BH-660 hybrid maize. The FYM used for the experiment was well decomposed under shade and spot applied together with the P fertilizer at planting; N was applied in split form. The residual effects of FYM were investigated for Laga Kalla, Walda and Shoboka during the 1998 cropping season. Statistical analysis revealed that the N/P fertilizers and FYM significantly (p 0.05) increased grain yield in all locations except for Walda in 1997. Interactions of FYM and NP fertilizer rates were significant (p ≤ 0.05) at all locations except for Shoboka. The application of FYM alone at rates of 4, 8, and 12 t ha−1 produced average grain yields of 5.76, 5.61 and 5.93 t ha−1, respectively, compared to 3.53 t ha−1 for the control treatment in 1997. There were significant residual effects of FYM and NP fertilizers applied in 1997 on maize grain yields in 1998. Laboratory analysis confirmed that considerable amounts of macronutrients and small amounts of micronutrients were supplied by FYM. Based on the results of this study, the integrated use of properly managed FYM and low rates NP fertilizers could be used for maize production in the areas under consideration. Moreover, sole applications of FYM on relatively fertile soils like Walda and Harato are useful in maintaining soil fertility and are encouraging for resource poor farmers

Changes in Land Cover and Soil Conditions for the Yabelo District of the Borana Plateau, 1973-2003

It has been proposed that the Borana Plateau has markedly changed in terms of land cover and land use in recent decades, but no hard data have been available to critically assess this claim. In addition, systematic analysis of soil properties has been limited. Research was designed to measure changes in land cover/land use over 30 years in the 400-km2 Yabelo District of southern Ethiopia using three satellite images taken at an average interval of 15 years. Samples were also collected to assess variation in the physical and chemical properties of dominant soils. Results indicated that Yabelo District has indeed changed greatly in terms of land use and land cover; dramatic declines were noted in the extent of grasslands, while croplands increased five-fold, and bushed-grasslands and bushlands both increased substantially. Bushland soils had less organic matter and were more compacted than grassland soils. These results all support the idea that the productive capacity of this landscape for grazing has been markedly reduced in 2003 as compared to that for 1973. Rehabilitating the grazing system would be difficult and require a comprehensive, inter-disciplinary approach. Central to such an approach would be devising a well-informed land use plan

Soil fertility status and wheat nutrient content in Vertisol cropping systems of central highlands of Ethiopia

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Phosphorus status, inorganic phosphorus forms, and other physicochemical properties of acid soils of Farta District, Northwestern Highlands of Ethiopia

Soil acidity and low availability of P limit crop production in the highlands of Ethiopia. The objective of this study was to determine the P status, distribution and forms of inorganic P and relate them to selected chemical properties of eight representative acidic surface soil samples from Farta District. Soil pH (H2O) varied between 4.74 and 5.50. The moderate to high CEC suggests that besides kaolinite, the soils also contain expandable 2 : 1 clay minerals. Though the total P content was high, the available Olsen P content was very low or low in all soils except one. In most soils, the abundance of inorganic P fractions was as follows: P bound by oxalate extractable iron (-P) reductant soluble Fe-P occluded Al-Fe-P P bound by oxalate extractable aluminum (-P) calcium bound P (Ca-P). Olsen P had a very strong positive correlation () with -P (), -P (), and oxalate extractable P (). Though Fe bound P reserves were quite abundant and the degree of P saturation of + (median 3.3%) was moderate, the extremely low P saturation of (median 0.5%) explains the P deficiency of the soils.Peer reviewe

Evaluation of the potential use of langbeinite (potassium sulfate / magnesium sulfate) as a reclaiming material for sodic and saline sodic soils.

Soil sodicity/salinity and scarcity of water are important constraints of agricultural development in arid lands. Excessive exchangeable sodium of sodic and saline sodic soils cause swelling of clays and dispersion of colloidal particles, and results in poor soil-water-air relationships. Reclaiming sodic and saline sodic soils involves the displacement of exchangeable sodium and its subsequent leaching from the root zone. This further depends upon the choice of chemical or cation to exchange for sodium and the quality and availability of water for leaching. Therefore, a series of experiments including soil characterization, laboratory batch studies, column leaching studies and greenhouse crop response studies were conducted to evaluate the potential use of langbeinite as a reclaiming material for saline sodic soil. Both the Grabe clay loam and the Guest clay soils met the requirements of a saline sodic soil category. The Grabe clay loam was more strongly saline sodic than the Guest clay soil, and was therefore used in the subsequent studies. In the batch studies involving a 1:1 soil:water extracts, langbeinite proved to be more efficient than gypsum in replacing exchangeable Na especially at higher levels of applied amendments. In the column studies, the amount of exchangeable Na displaced due to gypsum and langbeinite was the same when high amount (4 pore volumes) of water was used for leaching. However, langbeinite removed considerably higher amounts of sodium than gypsum with the use of lower volumes of leaching water. Accordingly, savings of over 9 acre-inch of irrigation water per acre of reclaimed land can be realized by using langbeinite over gypsum to lower the ESP of the soil to about 10% when both amendments are applied at a rate of 12 tons/ha. The hydraulic conductivity (HC) of the soil increased significantly due to application of both gypsum and langbeinite and decreased due to leaching with increasing pore volumes of water. Although steady state HC was not attained with the use of gypsum, the HC of the soil treated with gypsum was higher than the langbeinite treated soil after leaching with 4 pore volumes of water. Similarly, seed germination and dry matter yield of lima bean plants responded to the application of gypsum and langbeinite and leaching both with Safford irrigation water and Tucson tap water. Such responses both to the amendments and volumes of leaching water were of a higher magnitude with langbeinite than with gypsum

Effects of Mineral N and P Fertilizers on Yield and Yield Components of Flooded Lowland Rice on Vertisols of Fogera Plain, Ethiopia

Despite its very recent history of cultivation in Ethiopia, rice is one of the potential grain crops that could contribute to the efforts for the realization of food security in the country. However, the scientific information available with regards to the response of flooded rice to N and P fertilizers for its optimum production on Vertisols of Fogera Plain is very limited. Therefore, a field experiment was conducted on Vertisols of Fogera plain, northern Ethiopia to study the yield and yield components response of rice and to establish the optimum N and P fertilizer levels required for improved grain yield of flooded rice. Six levels of N (0, 30, 60, 90, 120 and 150 kg ha−1) and five levels of P (0, 13.2, 26.4, 39.6 and 52.8 kg ha−1) laid down in a randomized complete block design with four replications were used as treatments. Nitrogen was applied in two equal splits (50% basal and 50% at maximum tillering) as urea and the entire dose of P was applied basal as triple super phosphate at sowing. The main effects of N and P fertilizer levels showed significant differences (P ≤ 0.01) for all yield and yield components studied. The effects of N by P interaction were significant only for grain yield (P ≤ 0.05), number of panicles per m2 (P ≤ 0.01), number of spikelets per panicle (P ≤ 0.05) and plant height (P ≤ 0.01) among the different yield and yield components studied. Application of N and P significantly (P ≤ 0.01) increased grain yield of rice up to the levels of 60 kg N and 13.2 kg P ha−1. However, maximum grain yield (4282 kg ha−1) was obtained with the combined application of 60 kg N and 13.2 kg P ha−1, and the yield advantage over the control was 38.49% (1190 kg ha−1). Moreover, application of both N and P fertilizers have increased the magnitudes of the important yield attributes including number of panicles per m2, number of spikelets per panicle, panicle length, dry matter accumulation, straw yield and plant height significantly (P ≤ 0.01). Besides, grain yield was positively and significantly associated with number of panicles per m2 (r = 0.61∗∗), number of spikelets per panicle (r = 0.49∗∗), panicle length (r = 0.54∗∗), dry matter accumulation (r = 0.46∗), thousand grain weight (r = 0.41∗) and harvest index (r = 0.39∗). These indicate that N and P application increased grain yield of rice by positively affecting the important yield components of the crop. Therefore, taking the findings of the present study into consideration, it may be tentatively concluded that the farmers at the Fogera plain may apply a combination of 60 kg N and 13.2 kg P ha−1 to improve the grain yield of flooded lowland rice cultivated on heavy black clay soils (Vertisols) under rain fed conditions

Characterization and Fertility Status of the Soils of Ayehu Research Substation, Northwestern Highlands of Ethiopia

The pedogenic properties and fertility status of the soils at Ayehu Substation of the Amhara Region Agricultural Research Institute were studied both in the field and through laboratory analysis. On the basis of in situ description of two soil profiles and laboratory analysis, the soils of the study site qualified for the Nitisol soil group as per the FAO/UNESCO Soil Grouping System. The soils were moderately acidic in reaction and silty clay to clay in texture. The pedons exhibited increasing clay contents with depth qualifying for argillic (Bt) horizons. The surface horizons of both pedons revealed the lowest and the bottom (Bt3) horizons indicate the highest bulk density values. The consistent increase of bulk density with depth is apparently due to the decreasing level of organic carbon (OC) with depth from 2.6 to 0.6% in pedon 1 and from 2.8 to 1.1% in pedon 2. The lowest total porosity (44.2%) was observed in the Bt3 horizon of pedon 1 and the highest (55.2%) in the composite surface soil collected around pedon 2. Throughout the depths of the two pedons and surface soil samples, pH (H2O) values were higher than pH (KCl) resulting in positive pH values and indicating the presence of variable charge clay surfaces. The subsoil horizons showed lower values of cation exchange capacity (CEC) and percentage base saturation suggesting intensive weathering and presence of 1:1 (kaolinitic) clay minerals. The quantity of exchangeable Na was trace whilst appreciable amount of exchangeable K was available in both pedons. The surface horizons contained high exchangeable Ca and Mg to the extent that the sum of these bases occupied over 83% of the CEC in both pedons. In accordance with OC, total N decreased with depth from 0.19 to 0.05% in pedon 1 and from 0.22 to 0.10% in pedon 2. The highest contents of Olsen P (3.21 mg l-1) and Bray P (4.40 mg l-1) were obtained in the surface horizon of pedon 1 and both showed decreasing trends with depth in the two pedons. Application of increasing rates of P fertilizer increased both the Olsen and Bray II P consistently, while applied rates of N did not bring significant change in soil total N content

Soil Phosphorus Fractions as Influenced by Different Cropping Systems: Direct and Indirect Effects of Soil properties on Different P Pools of Nitisols of Wolayta, Ethiopia

Data from 12 surface soils (0 – 15 cm depth)of three cropping systems (enset, maize and grazing land) and path analysis was used to evaluate effects of soil properties: pH, texture (Clay, silt and sand) , organic carbon (OC) cation exchange capacity (CEC),citrate-dithionite-bicarbonate (CDB) extractable Fe and Al (Fed and Ald) on total phosphorous (Pt), organic phosphorous (Po), Olsen P (Available P) and Chang and Jackson (1957) inorganic phosphorous (Pi) fractions. Correlation analysis was performed to study the relationships between soil properties and different soil P pools while path analysis model was used to evaluate direct and indirect effect of these soil properties on the P pools. Only soil properties that significantly contribute to the fit of the model were used. High significant values of coefficient of determination (R2) and low values of uncorrelated residual (U) values indicate the path analysis model explains most of the variations in soil Pt, Po, Olsen-P, Saloid-P, Ca-P, Al-P, and Fe-P pools. Soil pH had significantly high and positive direct effect (D = 0.618*) on Pt, (D = 1.044***) on saloid P, and (D = 1.109***) on Fe-P with modest and negative indirect effect (D= -0.478 and -0.405) on saloid P and Fe-P, respectively, through OC. The direct effect of clay on Ca-P, Al-P and Fe-P (readily available P forms) was significant and negative with a relatively higher indirect effect on Fe-P through pH suggesting that clay is dominant soil property that influences readily available P pools in Nitisols of the study area. Fed had significant and negative direct effect (D = -0.430*) on Olsen available P with low negative indirect effect ( D = -0.154) through pH results in significant and negative correlation (r = -0.657*). The significant and negative direct effect of Fed on Olsen P indicates that crystalline iron is the sink for available P. Relative influence of the soil properties on the soil P pools was in the order: pH > clay > Fed > OC.  These results show that most of P pools of Nitisols of Wolayita are best predicted from pH, clay (texture), Fed and OC. On the other hand, our data also show that the inclusion of other soil variables is needed to fully predict Ca-P and stable P pools