RESUMO
Understanding soil property and crop yield responses to variations in land use and topographic gradient is vital for designing targeted soil and agronomic management practices. This study investigated the interrelationships between land use, topographic position, soil properties, and crop yield. Three replicates of three land use types - enset agroforestry, cropland (annual crop), and grazing land - were selected along a toposequence (upper, middle and lower) for the study. A total of 54 composite soil samples were collected and analyzed. Grain yield and above ground biomass were also gathered from the cropland and analyzed. Soil profile descriptions revealed notable variations in soil physical properties, including soil texture, bulk density, color, horizons, and depth among the pedons of the three topographic positions. Clay and silt fractions exhibited significant differences between land uses and topographic positions, while the sand fraction was influenced by topographic position alone. Crop and grazing lands displayed higher clay content compared to the enset field. A decreasing trend in clay fraction was observed from upper to lower topographic positions. The enset field had significantly higher soil pH, OC, TN, and K+ contents than crop field. A significantly higher available P of 16.61 mg kg-1 was measured from lower slope position followed by 14.08 mg kg-1 in middle slope. The upper slope position had the highest exchangeable acidity of 3.09 cmol(+) kg-1), followed by middle slope with 2.77 cmol(+) kg-1), 2.45 cmol(+) kg-1) in the lower slope position. Grain yield and above ground biomass decreased from lower slope to middle slope and upper slope positions. These observed variations in soil properties and crop yield among land uses and topographic positions underscore the necessity for tailored soil management strategies and agronomic practices specific to land use types and the specific localized topographic conditions to optimize agricultural productivity.
RESUMO
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.
RESUMO
Soil fertility in smallholder farms remains a major issue in Ethiopia and for many developing countries where more than 90% of the population's food is provided by smallholder farmers. This study was aimed to identify determinants of soil fertility management practices in smallholder farmers of the Gedeo zone, southern Ethiopia where the agricultural landscapes dominated by coffee and enset crops. The study is based on cross-sectional data obtained from a total of 270 randomly selected households. Data were collected using a structured survey questionnaire and focus group discussion (FGD) held with key informants from each sample kebele. The data collected were analyzed using descriptive and inferential statistics, and a logistic regression model. The result of the study showed that to maintain soil fertility the majority of farmers relied on a number of organic farming practices that take full advantage of the nutrient cycles. The commonly used soil fertility management practices were green manure (98.1%), mulching (71.9%), minimum tillage (97.4%) and multilayered agroforestry (100%). The results showed that the socioeconomic status of farmers had an effect on the adoption of soil fertility management practices. Logistic regression analysis showed that the family size of the household had a positive significant (p < 0.05) effect on the adoption of compost and farmyard manure while the dependency ratio of the farmer households had a negative impact on both compost and farmyard manure adoption. The differences in education status of household head and coffee shrubs holding had a strong positive relationship with farmers' mulch adoption. The study also shows that livestock holding of the household was significant (p < 0.01) positive association with the adoption of farmyard manure. Moreover, the coefficient for the agriculture annual income and differences in agroecological zones had strong positive effects on the adoption of compost at and cover cropping. The findings suggest that soil fertility management practices in the study area could be enhanced by improving the income of farmers and targeting young families where all spouses and working-age household members work on farms. Moreover, attention should be given to enhancing intensive livestock management systems that support more livestock for the provision of farmyard manure and advising farmers to possess a manageable number of coffee shrubs.
