Selected Soil Physicochemical Properties Research Articles

Effect of Eucalyptus globulus Plantations on Soil Physicochemical Properties in the Upper Blue Nile, Ethiopia

In recent years, there has been a substantial conversion of croplands and grasslands to short rotation Eucalyptus globulus plantations in the northern highlands of Ethiopia. This has raised concerns among researchers, policymakers, and environmentalists regarding potential adverse effects on soil fertility. To address these concerns, a study was conducted to evaluate the impact of Eucalyptus globulus plantations on selected soil physicochemical properties in the region. The study involved four land-use types, comprising two age groups of Eucalyptus globulus plantations (4-year-old and 9-year-old), as well as areas designated for grasslands and croplands. Soil sampling was carried out in 10 m × 10 m subplots within each experimental plot, and standard methods were employed for soil analysis. The soil laboratory results were statistically analyzed using Two-way ANOVA and Pearson’s correlation coefficients in R software version 4.1.0. The findings revealed significant variations (p<0.05) in soil bulk density, soil organic carbon, and soil pH between the 4-year-old and 9-year-old Eucalyptus globulus plantations and the grasslands. A notable difference (p<0.05) in exchangeable acidity was observed between the 4-year-old and 9-year-old E. globulus plantations, with the latter exhibiting the highest mean exchangeable acidity (6.20 ± 0.76). However, no significant differences (p<0.05) were observed between the Eucalyptus plantations and the grasslands in available phosphorus (Av.P), exchangeable calcium (Ca2+), sodium (Na+), and magnesium (Mg2+) concentrations, as well as cation exchange capacity (CEC). The study results has, therefore, implied that Eucalyptus globulus plantations induced changes in specific soil properties with varying stand ages in the study area. Nonetheless, it was emphasized that further long-term research is necessary to comprehend the effects of these plantations on soil properties.

Short Term Effect of Vermicompost on Soil Chemical Properties under Maize (Zea mays L.) Field in Northern Ethiopia

Aim: The application of vermicompost (VC) to improve soil chemical properties in area that have low soil fertility status is crucial. Thus, the present study was initiated to determine impact of vermicompost on selected soil physicochemical properties. Study Design: The experiment had 7 treatments arranged in a Randomized Complete Block Design (RCBD) with five replications. Place and Duration of the Study:  Hence, a field experiment was carried out in 2018 main cropping season at farmer's field at Adiha village in Kolla Tembien district, Tigray, Ethiopia. Methodology: The treatments were 5 levels of VC (0, 2.5, 5, 7.5 and 10 t ha-1), the recommended rate of N and P (46 N and 46 P2O5 kg ha-1), compost at rate of 10 t ha-1 and control. Surface soil samples were collected before planting and after maize harvesting at a depth of 0-30 cm to analyze selected soil chemical properties such as pH, extractable electric conductivity (ECe), cation exchange capacity (CEC), total nitrogen (TN), available P and exchangeable bases (K, Mg, Ca, and Na). Likewise, vermicompost and compost nutrient contents were also analyzed to know their nutrient composition. Results: Soil analysis results before sowing revealed that most of the soil chemical properties were rated as low. However, vermicompost application significantly (P≤0.05) improved the soil chemical properties. The studied soil chemical properties such as OC (1.33%), TN (0.13%), CEC (17.2 Cmol (+) kg-1), and available P (6 .38 mg kg-1) showed an improvement at VC 10 t ha-1rate as compared to the control which was respectively 0.65%, 0.04%, 7.4 Cmol(+)kg-1 and 2.45 mg kg-1.   Conclusion: A significant (P≤0.05) increase in OC, TN and available P was observed with increased vermicompost rate under cultivated land.

Age of Soil and Water Conservation Practices on Selected Soil Properties along the Toposequence of Gerado Watershed, Habru District, Eastern Amhara, Ethiopia

The government of Ethiopia through community participation has widely implemented soil and water conservation (SWC) measures, especially in the highlands of Ethiopia. However, the effects of these practices on the physicochemical properties of soils have not been well assessed and documented in the study area. Thus, this experiment was conducted to evaluate the effects of SWC practice on selected soil physicochemical properties. Treatments were nonconserved land, 3- and 9-year-old soil conservation practices under three slope positions, namely, lower slope (0–8%), middle slope (9–15%), and upper slope (>15%) positions, and at two soil depths (0–20 and 20–40 cm) with three replications. Accordingly, 54 composite soil samples were collected and analyzed based on standard procedures. The results showed that the age of soil and water conservation practice, topography, and soil depths significantly affected most of the soil properties. Conserving the watershed for nine years improved the subsoil clay content from 37.1 to 46.3%, subsoil soil moisture content from 13.38 to 24.61%, surface total nitrogen content from 18.1 to 81%, available phosphorus content from 13.1 to 33.5 mg kg−1, surface organic carbon from 0.28 to 2.83%, soil carbon stock from 9.26 to 35.59 t ha−1, and surface cation exchange capacity from 21.5 to 57.4 Cmolec kg−1. Therefore, maintaining soil and water conservation practices for long periods can improve soil properties. However, planting different grasses, with the existing physical structures is needed to increase soil nutrient and carbon stock.

Examining the Effect of Combined Biochar and Lime Rates on Selected Soil Physicochemical Properties of Acid Soils in Gimbi District, Western Ethiopia

The physicochemical properties of Western Ethiopian soils were negatively threatened with continuous cultivation crop lands. Soil amendments with biochar and lime facilitate and improve soil physicochemical properties directly and indirectly and enhance crop productivity. A field experiment was conducted in Gimbi District, Western Ethiopia, to examine the effects of combined coffee husk biochar (CHB) and soil test value-based lime (STV) rate application on physicochemical properties of acid soils. The trial included eight treatments, including control, 100% STV, 10 ton of CHB, and CHB + STV rates at 10 ton + 75%, 10 ton + 50%, 7.5 ton + 75%, 7.5 ton + 50%, and 5 ton + 75% ha−1on two farm fields. The fields were laid out in RCBD with three replications. The treatments had substantial effects on P<0.05) on the soil’s physicochemical characteristics. The application of biochar and lime in Farms-1 and 2 reduced soil BD from 1.21 and 1.41 g·cm−3 to 1.15 and 1.12 to 0.90 and 0.97 g·cm−3, respectively. The soil pH level was increased from 5.10 to a range of 5.58 to 6.11 in Farm-1, and in Farm-2, from 4.64 to a range of 4.64 to 6.22 levels. The application of 10 ton of CHB + 75% of STV in Farms-1 and 2 resulted in the highest SOC of 7.44% and 7.68%, respectively. The application of 10 ton of CHB + 75% of STV in Farms-1 and 2 resulted in 4.86 mg·kg−1 and 6.96 mg·kg−1 available P, respectively. Available P was positively correlated with pH (0.62), SOC (0.63), and CEC (0.66). Exchangeable acidity was decreased from 4.64 cmol(+)kg−1 to a range from 3.19 to 0.98 cmol(+)kg−1 in Farm-1 and from 5.00 cmol(+)kg−1 to a range from 3.38 to 1.10 cmol(+)kg−1 in Farm-2. Therefore, amending the strongly acidic to very strongly acidic soil with a combined CHB (7.5 to 10 ton ha−1) and STV (50 to 75% ha−1) rates had improved the soil physicochemical properties of agricultural lands. To make a firm conclusion, research on soil analysis after crop harvest and economic benefit is required.

Reuse of Treated Wastewater for Crop Irrigation: Water Suitability, Fertilization Potential, and Impact on Selected Soil Physicochemical Properties

This study evaluates the suitability of treated wastewater (TWW: secondary effluent and membrane effluent) for crop irrigation and the resultant impact on crop growth and soil physicochemical characteristics. Carrot seeds (Daucus carota subsp. sativus) were grown on loam soil and irrigated with tap water (Tap), secondary effluent (SE), and membrane effluent (ME) until maturity. Bacteriological analyses showed four log counts of E. coli and thermotolerant coliforms for secondary effluent, making it unsafe for the irrigation of carrots. Tap water and membrane effluent fulfilled the microbial limit for water reuse and were suitable for irrigation. The sodium absorption ratio, Kelly index, and magnesium hazard assessments indicated that all three irrigation water streams were suitable for irrigation. The average mass of carrot fruits for Tap, SE, and ME was 2.14 g, 3.96 g, and 3.03 g, respectively. A similar trend was observed for the dry matter composition: Tap had 15.9%, SE had 18.3%, and ME had 16.6%. The soil pH increased from 7.08 to 7.26, 7.39, and 7.33 for tap water-, secondary effluent-, and membrane effluent-irrigated soils, respectively. Nitrate-nitrogen and potassium levels increased in the TWW-irrigated soil, while that of the tap water-irrigated soil decreased. Sodium levels in the TWW-irrigated soil increased significantly but did not induce soil sodicity. The application of the TWW enhanced the growth of the carrot plants and increased the soil nutrient levels. Hence, using TWW in agricultural irrigation could promote food production and also limit the overdependency on freshwater resources. However, TWW should be disinfected by using UV disinfection and ozonation to reduce the risk of microbial contamination. Such disinfection methods may not lead to the formation of toxic byproducts, and therefore secondary pollution to crops is not anticipated.

Effect of Bench Terreces on Selected Soil Physico Chemical Properties in Andit Tid Watershed, North Shoa, Ethiopia

Effect of Bench Terreces on Selected Soil Physico Chemical Properties in Andit Tid Watershed, North Shoa, Ethiopia

Effect of conservation tillage on soil and water conservation, yield and yield components of Maize (Zea mays L.) in South Ari District, Southern Ethiopia

Reduced tillage is one of the options to combat land degradation problems. The study aims to examine the impacts of tillage practices on selected soil physicochemical properties, soil loss, and maize yield and yield components. Four treatments—zero, twice, and strip tillage—as well as farmers' practices, were set up in a randomized complete block design with five replications. Then, soil moisture, soil loss, and yield and yield components of maize data were collected. The findings show that, when compared to conventional tillage, conservation tillage improves soil moisture and decreases soil loss during and after crop development. The study found that implementing reduced, or zero tillage practices resulted in higher maize yields and long-term economic benefits for farmers compared to conventional and strip tillage practices. In addition, the current research demonstrated that, in comparison to strip tillage and conventional tillage, adopting reduced tillage and zero tillage increased maize yield and yield components with greater long-term economic benefits to farmers. The current findings also showed that adopting reduced tillage and zero tillage boosted maize yield and yield components, with higher economic benefits to farmers in the long run as compared to strip tillage and conventional tillage. Although zero tillage attributed to less grain yield, it resulted in higher economic benefits to farmers and saved 44.84% of soil loss relative to conventional tillage. The outcome of the economic evaluation unequivocally demonstrated that reduced tillage is the best approach, but zero tillage, strip tillage, and reduced tillage are all superior and advised for farmers. Hence, farmers can use either zero tillage or reduced tillage, depending on their investment capital. But to get considerable changes in soil and water balances, other soil physicochemical properties, and crop yield. Similar studies must be carried out on permanent field plots for longer than 2 years in the future.

Soil Fertility Status as Influenced by Slope Gradient and Land Use Types in Southern Ethiopia

Understanding the effects of land use types and slope gradients on the physicochemical properties of soil is essential for sustainable soil management. Therefore, this study was conducted at the Azit subwatershed of Gedebano Gutazer Welene Woreda, Southern Ethiopia, with the objectives to evaluate the effect of land use types, examine the interaction of land use and slope gradient, and evaluate the effect of slope gradient on selected soil physicochemical properties. A total of 27 soil samples using a simple random sampling technique with randomized complete block design from 3 land use types (cultivated, eucalyptus, and grazing lands) ×3 slope gradients (upper 10–15%, middle 5–10%, and lower 2–5% slopes) ×3 replications and depth (0–20 cm) were collected. Results indicated that most of the physicochemical properties of soils were significantly ( P < 0.01 ) affected by land use and slope gradient. Silt and sand particles did not vary significantly ( P > 0.05 ) among the land use types. The interaction effect of land use and slope was not significant ( P > 0.05 ) for most of the soil properties except for organic carbon (OC). Results of data analysis also showed that soil fertility was low under cultivated and eucalyptus lands coupled with the upper slope gradient. Therefore, based on the study’s findings, it can be recommended that integrated soil fertility management practices, such as the addition of soil organic matter and appropriate use of inorganic fertilizers, need to be implemented to restore the lost soil fertility status on the cultivated land and ultimately increase agricultural productivity on a sustainable basis. Eucalyptus plantings should also gradually be replaced by those that assist the soil in restoring its fertility.

Comparative analysis of effects of climate-smart agriculture practices and conventional agriculture on selected soil physicochemical properties in Nyimba district, Zambia

Background. Many smallholder farmers in the developing world live in adverse poverty and rely on agriculture as their primary source of income and household food. In Zambia, agriculture production is the main activity for people in rural areas of the country. The study evaluated the effects of climate-smart practices: Gliricidia sepium alley cropping, conservation agriculture basin, ripping, and conventional agriculture cropland on selected physicochemical properties of soil among smallholder farmers’ croplands in Nyimba district, Zambia. Materials and Methods. Cropland under conservation agriculture basin, ripping, agroforestry gliricidia alleyed cropping, and conventional agriculture cropland hosting the practices for more than five years were considered for soil sample collection. Thirty (30) composite soil samples were collected: gliricidia alley cropping (n = 6), conservation agriculture ripping (n = 6), basin (n = 6), conventional agriculture one (n = 6), and conventional agriculture two (n = 6) following a zigzag pattern on soil surface depth of 0–30 cm. The collected composite soil samples were analyzed at the University of Zambia Soil Science Laboratory. Soil laboratory results were analyzed with Minitab Statistical Software version 17 for mean squares, standard deviations, and Tukey’s LSD. Results and Discussion. The study revealed significant effects (p <0.05) of gliricidia alley cropping, conservation agriculture ripping, and basin on soil bulk density, porosity, power of hydrogen (pH), cation exchange capacity, available phosphorus, total nitrogen, exchangeable bases sodium, calcium, and potassium. Exchangeable base magnesium was recorded as insignificant across the considered practices off-course with minimal mean variations with conventional agriculture cropland. Conclusion. The study shows that implementing climate-smart agriculture practices has the potential to improve crop productivity per hectare through reclaiming and amending depleted soil physicochemical properties in a mid and long run. This also indicates the importance of climate-smart agricultural practices implementation among smallholder farmers’ cropping fields.

Effects of land use and slope position on selected soil physicochemical properties in Tekorsh Sub-Watershed, East Gojjam Zone, Ethiopia

Abstract In the Tekorsh Sub-Watershed, East Gojjam Zone, Ethiopia, researchers investigated the impact of land use patterns and slope position on selected soil physico-chemical parameters. The study area was arbitrarily divided into three slope positions (higher, middle, and lower), two land uses types (grazing and cultivated land), and two soil depths (0–20 and 20–40 cm) with three replications, based on the in situ field survey. For laboratory analysis, a total of 36 composite samples were obtained. Sand, clay, and silt fraction were highly significantly (P ≤ 0.05) affected by the interaction effect of the three factors. Clay and clay loam were the textural classes of the soil in the study area. The interaction effects of the three factors were highly significant (P ≤ 0.001) affected bulk density (D b), total porosity (TP), organic carbon (OC), available phosphorus (AP), exchangeable (Mg2+, Ca2+, and acidity), cation exchange capacity (CEC), and micronutrients (Fe, Mn, Cu, and Zn). The soils were medium to high (1.22–1.44 g/cm3) in D b, very high (45.66–63.13%) in TP, medium to high (15.72–19.56% v/v) in available water holding capacity, low to medium (1.37–2.91%) in OC, very low (1.65–7.68 mg/kg) in AP, high (4.62–5.36 cmol(+)/kg) in exchangeable Mg2+, very high in CEC (43.60–51.06 cmol(+)/kg), Fe (25.20–52.91 mg/kg), Mn (37.29–105.55 mg/kg), Cu (4.04–7.87 kg/kg), and Zn (0.83 2.53 kg/kg). In general, it was discovered that the majority of the assessed soil properties were better in grazing land than in soils utilized for cultivated land uses, and that the lower slope position was preferable to the upper and middle ones.

Effects of Soil and Water Conservation Practices and Slope Gradient on Selected Soil Physicochemical Properties in Ejersa Watershed, Toke Kutaye District, Ethiopia

This study was conducted to assess the effects of soil and water conservation practices and slope gradients on selected physicochemical properties of soil at Ejersa Watershed based on a total of 18 composite soil samples collected and analyzed using standard laboratory procedures. The values of pH, electrical conductivity, cation exchangeable capacity, organic carbon, organic matter, total nitrogen, and available phosphorus determined in soil samples collected from conserved and nonconserved plots were 6.4 and 6.16, 40.26 mS/m and 15.12 mS/m, 33.51 meq/100 g and 21.56 meq/100 g, 2.66% and 2.24%, 4.58% and 3.86%, 0.24% and 0.15%, and 29.45 ppm and 17.68 ppm, respectively. Soil pH, electrical conductivity, moisture, total nitrogen, and available phosphorus were significantly different ( p < 0.01 ) between treated and untreated plots and among the slope classes. Values of soil organic carbon and organic matter showed significant differences ( p < 0.05 ) between land types but not among the slope classes. Soil cation exchange capacity showed significant difference ( p < 0.05 ) between land types as well as among the slope classes. Relatively, higher values of many of the physicochemical parameters were recorded in samples collected from the treated land and lower slopes which might be attributed to the deposition effects of the conservation practices and decline in the rate of soil erosion.

Assessment of soil water retention characteristics based on VNIR/SWIR hyperspectral imaging of soil surface

This paper aims to create supervised classification models of the soil water potential based on hyperspectral data of Polish mineral soils (104 samples) from the Visible and Near-InfraRed (VNIR) and Short-Wave InfraRed (SWIR) range and selected soil physico-chemical properties, such as organic carbon content, or fraction of sand, silt, and clay. Soil water content regression models were also created, which took into account the soil water potential ranging from 98.1 J∙m-3 to 1554249 J∙m-3. Several machine learning algorithms were tested to create models of the soil water potential and the soil water content. It occurred that reflectance characteristics of the soils exhibit a high correlation with soil moisture. Gaussian Processes (GP) model was most suitable for the estimation of the soil water content, regardless if input data contained pure reflectance spectra (R=0.82), or if they were supplemented with selected physico-chemical soil properties and soil water potential (R=0.94). No improvement of the models’ accuracies was noticed when only the selected soil physical and chemical properties were included as inputs, which suggested that the soil surface spectral data contained in themselves information, which strictly belonged to specific soil physico-chemical properties. Among classification models of the soil water potential, the LOG method had the highest percentage of correctly classified cases. More than 65% of all cases were correctly classified if the spectral data, moisture, and other properties of the tested material were included, and more than 54% when the independent variables did not include soil moisture. The majority of misclassified cases were by one class. The greatest accuracy was achieved for the two extreme values of pF (0 and 4.2), while the worst one was for pF2.2 and pF2.7.

The effect of land use type on selected soil physicochemical properties in Shihatig watershed, Dabat district, Northwest Ethiopia

Different land use practices have a substantial influence on soil quality. An inappropriate land use system in Ethiopia leads to extensive deforestation which aggravates the loss of soil fertility. Even though there are various studies conducted on the effect of land use type on soil physicochemical properties, it is inadequate in the northern highlands of Ethiopia, in particular in the Dabat district. Thus, this study aimed to assess the effect of land use type and soil depth on selected soil physicochemical properties in the Shihatig watershed, Northwest Ethiopia. A total of 24 undisturbed core and disturbed composite soil samples were collected from the four land use types (natural forest, grazing, cultivated, and Eucalyptus lands) and two depths (0–20 cm and 20–40 cm) with three replications. The physicochemical properties of the soil were determined using standard operating procedures. The two-way analysis of variances was conducted using SAS software, Version 9.4. The result showed that the texture and soil organic carbon were affected by land use type, soil depth, and the interaction of the two factors; while bulk density, soil moisture content, total nitrogen, available phosphorus, cation exchange capacity, and level of Mg2+ were significantly affected by both land use and soil depth, whereas pH and electrical conductivity were affected by only the land use type. The highest clay, pH, electrical conductivity, total nitrogen, cation exchange capacity, and exchangeable cations (Ca2+ and Mg2+) were recorded in the natural forest land, while the lowest values of the same parameters were found under cultivated land. The mean values of most of the soil properties were low in the cultivated and Eucalyptus lands. Therefore, adopting sustainable cropping systems such as crop rotation and the addition of organic manure, and minimizing planting the Eucalyptus tree is vital to improve the existing soil quality and enhance crop productivity.

Effects of land-use-cover-changes on selected soil physicochemical properties along slope position, Coka watershed, Southern Ethiopia

Land-use changes along slope position can have a major positive or negative impact on soil environment and agricultural productivity. Relevant information to understand the negative effect of land-use change and slope variability on soil property is a vital element to monitor, plan and make the decision to improve productivity and restore the environment. The aim was to examine the effects of land-use-cover-changes along slope position on the selected soil physicochemical properties in the Coka watershed. Soil samples were gathered from 5 nearby land uses, namely forestland, grassland, bushland, cultivated land, and bare-land, and 3 slope positions (upper, middle, and lower slope) at 0–30 cm soil-depth, analyzed in Hawassa University Soil testing laboratory. The results show that the highest field capacity, available water-holding, porosity, silt, nitrogen, pH-value, cation exchange capacity, sodium, magnesium, and calcium were in forestlands and lower-slope. The highest water-permanent-wilting-point, organic-carbon, soil-organic-matter, and potassium were in bushland; bulk density was in bare land while the highest clay and available-phosphorus were revealed in cultivated land and lower slope. Most soil properties showed a positive correlation with each other except bulk density which has a negative correlation with all soil properties. Generally, cultivated land and bare land have the least concentration in most soil properties which indicates of increasing degradation rate in the area. Thus, soil-organic-matter and other yield-limiting nutrients should be improved in cultivated land to maximize productivity by using an integrated implementation of soil fertility management through cover crops and rotation, compost, manures, and minimum tillage; and amending soil pH-value by liming.

Effects of vegetation succession on topsoil C, N, and P contents and stoichiometry following agricultural abandonment in a representative karst trough valley

Soil carbon (C), nitrogen (N), and phosphorus (P) are significantly altered by vegetation succession under execution of ecological restoration projects in China. However, the changes in soil C, N, and P contents and their molar ratios as affected by vegetation succession are elusive in fragile karst ecosystems. With space-for-time substitution, this study compared the soil C, N, and P contents and their molar ratios between different vegetation successional stages in a representative karst trough valley, Southwest China. Soil samples from four positive vegetation successional stages, including herb stage (HE), hern-shrub stage (HES), shrub stage (SH), and secondary forest stage (SF), were collected to determine the topsoil C, N, and P contents and molar ratios, and selected soil physicochemical properties. The results showed that soil C and N contents increased by 158.4% and 39.6% from HE to SF, respectively, while soil P content was not significantly affected by vegetation succession. From HE to SF, soil C:N and C:P ratios increased by 82.1% and 134.2%, but soil N:P ratio vary insignificantly, respectively. Soil bulk density (BD) and pH increased but electrical conductivity (EC) decreased markedly from HE to SF. Soil exchangeable K+, Ca2+, and Mg2+ contents did not differ among four successional stages. Soil pH, BD and exchangeable K+ were closely correlated with C and P contents, C:P, and N:P in different successional stages. Our results imply that vegetation succession driven by ecological restoration considerably increases topsoil C and N accumulations but equalizes P in the karst trough valley.

Impacts of soil and water conservation measures on soil physicochemical properties in the Jibgedel Watershed, Ethiopia.

Soil erosion significantly affects agricultural production. Soil and Water Conservation (SWC) measures have been constructed to reduce soil loss. However, the impact of SWC measures on physicochemical soil properties has rarely been investigated in most parts of Ethiopia. Therefore, this study was designed to evaluate the effects of SWC measures on selected soil physicochemical properties in the Jibgedel watershed, West Gojjam zone, Ethiopia. The study also assessed the farmers' perception of the benefits and impacts of SWC measures. Composite and core soil samples were taken at a depth of 0 to 20cm from four farmlands with SWC measures (soil bund, stone bund, and soil bund with sesbania tree) and without SWC measures in three replications. Results have shown that employing SWC measures in the farmland significantly improved most of the physicochemical properties of the soil compared to farmland without SWC measures. Bulk density from soil bund with and without sesbania trees was significantly lower than stone bund and untreated farmland. Soil organic carbon, total nitrogen, electrical conductivity, and available phosphorus from soil bund with sesbania tree were significantly higher than other treatments. The result also revealed that most farmers perceived that the implemented SWC measures improved soil fertility and crop yield. SWC measures are easier to adopt for integrated watershed management when farmers are well-versed in them.

Variability analysis of soil properties, mapping, and crop test responses in Southern Ethiopia

Agricultural productivity is significantly impacted by soil properties, which vary spatially from a small to a larger area. This variation may be caused by a combination of intrinsic and extrinsic factors, including human activities like soil management practices. The aim of the current study was to analyze soil spatial variability, create a Digital Soil Map (DSM), and test map information with crop in Southern Ethiopia. A total of 18 geo-referenced surface soil samples at depth of 20 cm were collected. Selected soil Physico-chemical properties such as soil texture, pH, organic carbon (OC), total nitrogen (TN), available phosphorus (av. P), sulfur (S), exchangeable bases [calcium (Ca), magnesium (Mg), and potassium (K)], soil micronutrients [boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn)] and cation exchange capacity (CEC) were analyzed. The results revealed clay texture with a mean pH value of 4.6 (strong acidity). About 50% of essential nutrients [N, P, S, Ca, Mg, B & Fe] were deficient. The geostatistical analysis has shown that the best-fitted models were exponential for (OC, TN, available P, S, Mg, CEC, B, Fe, and Zn), spherical for (pH, Ca, Cu and Mn), and Gaussian for (C:N, K, K:Mg, and PBS). The range of all soil properties varied from 50 m to 84 m which was above the actual distance between soil samples (i.e., 46 m). The result showed that the spatial dependence values for soil properties of [OC, TN, CEC, PBS, ESP, and Cu]; [pH, C: N ratio, available P, S, Ca, Mg, K, Na, K: Mg ratio and Zn] and [B, Fe, M n] were strong (<25%]; weak (>75%) and moderate (25%–75%), respectively. Model performance using indicators such as prediction mean error (PME), root mean square standardized error (RMSSE), mean standard error (MSE), and root-mean-square error (RMSE) also confirmed the acceptable prediction. The DSM demonstrated the limitation of N, P, S, and B nutrients for intervention. The DSM information was tested under field conditions using haricot bean (Phaseolus vulgaris) with lime and organic fertilizers as treatments. The experiment consists of lime rates (0, 3, 6 t/ha), rhizobium inoculation (inoculated and non-inoculated), and fertilizer types (0, 150 kg ha−1 NPSB, 5 t/ha vermi compost, 10t/ha farmyard manure (FYM)) in Randomized Complete Block Design with three replications. The result exhibited interaction effects of lime, inoculation, and fertilizer types significantly influenced (p < 0.05) biomass and grain yield of haricot beans. Rhizobium inoculation x 6t/ha lime x 150 kg ha−1 NPSB recorded the maximum grain yield (3186.1 kg/ha) which was 26.3 fold over the non-treated soil (117 kg ha−1). In conclusion, the DSM classified the area into distinct management zones which were tested with a crop trial. The results of the trial confirm the importance of site-specific nutrients/amendment application for sustainable soil management.

Effect of Soil and Water Conservation Measures in Different Slope Classes on Selected Soil Physicochemical Properties at Addis Zemen District, Ethiopia

Soil and water conservation actions on erosion hotspot areas of cultivated lands in the Addis Zemen district have been prioritized for over a decade. However, the impact of these treatments on soil physicochemical parameters in different slope classes was neither examined nor quantified. As a result, the purpose of this study was to investigate the effects of soil and water conservation strategies on specific selected soil parameters on cultivated lands in varied slope gradients at the Michael Deber micro watershed. The experiment was set up in a split-plot design, with three slope classes as the main plot and four conservation measures as subplots that were reproduced three times each. Each plot had composite soil samples collected from 0-20 cm soil depth using a sampling augur, air dried, and prepared for investigation of soil chemical and physical parameters according to conventional lab protocols. The data was analyzed statistically with R software, and significant treatment means were separated using the least significant difference (LSD) at 5%. Clay, MC, pH, CEC, Ex. p, OC, and Av. P were found to be highly substantially (p

Impact of chemical fertilizers on diversity and abundance of soil-litter arthropod communities in coffee and banana plantations in southern Rwanda

Few studies explored effects of chemical fertilizers on diversity and abundance of soillitter arthropods in the tropics. To fill this gap, a study focussed on the abundance of soil-litter arthropods and selected soil physicochemical properties in coffee plantations treated with chemical fertilizers and in plantations of coffee and banana treated with organic fertilizers and organic mulches in southern Rwanda. Each land use was replicated three times. Soil-litter arthropods were collected using pitfall traps and hand collection. They were identified to the family level using dichotomous keys. Soil have been collected using auger and taken to the laboratory for the analysis of soil pH, soil organic carbon, total nitrogen, phosphorus, and cation exchange capacity. Findings indicated a total of 12,945 individuals distributed into 3 classes, 16 orders, 50 families and 92 morphospecies, with higher abundance and diversity in coffee plantations treated with organic fertilizers and organic mulches. Collected soil-litter arthropods were mainly classified in the class Insecta, dominated in numbers by ants (Hymenoptera: Formicidae), while Coleoptera and Hemiptera had more families. However, soil under coffee plantations treated with organic fertilizers and organic mulches was acidic compared with the soil under coffee plantations treated with inorganic fertilizers and banana plantations treated with organic fertilizers and organic mulches. The relationships between soil-litter arthropods and soil physicochemical properties suggest that soil-litter arthropods respond to the land use independently from soil physicochemical properties. We recommend further studies in coffee and other crop plantations in other regions of Rwanda to verify the findings of this study.

Selected physical and chemical properties of soil under different agroecological zone in Gedeo Zone, Southern Ethiopia

Soil fertility is the ability of the soil to provide favorable chemical, physical and biological characteristics to sustain plant growth. Its physicochemical properties are greatly influenced by altitude and farmer wealth status. This study aimed to examine the differences in selected soil physicochemical properties under three agroecological zone based on altitude gradient (upper, middle, and lower) and wealth class (rich, medium, and poor) in the organic agriculture dominant area of the Gedeo zone, southern Ethiopia. Soil samples were collected from the field under organic agriculture. A total of 216 composite soil samples 3(altitude) 12 (wealth class) 3(replication) and 2 soil depth (0–30 and 30–60 cm) were collected and analyzed for some selected soil physical and chemical properties using standard soil analytical procedures. Data were subjected to a two-way analysis of variance to determine the effects of agroecological zones and wealth status of households on the soil properties. The result showed that soil physical properties such as sand (p < 0.01), clay (p < 0.05) and bulk density (BD) (p < 0.01) were significantly affected by altitudinal gradients. Soil organic carbon (SOC), cation exchange capacity (CEC), total nitrogen (TN) and phosphorus (P) were in the suitable range for agricultural soil, suggesting that the organic agricultural practices employed in the study area might be contributed to improved soil fertility. Soil pH (H2O, (p < 0.01), CEC (p < 0.05), SOC % (p < 0.001), TN % (p < 0.05), P(p < 0.001) and K (p < 0.05) were significantly varied due to difference in agroecological zone. Similarly, wealth class of farmer had significant influence on soil pH (H2O) (p < 0.001), SOC (p < 0.001) and P (p < 0.001). The results highlight the importance of the agroecological zone and wealth status of farmer households on soil fertility improvements in the study area. Hence, during the implementation of the soil fertility policy, considering the altitude and wealth status of the farmer is recommended to improve soil fertility.