Explaining Soil Fertility Heterogeneity in Smallholder Farms of Southern Ethiopia

Abstract

Soil is spatially heterogeneous and needs site-specific management. However, soil nutrient information at larger scale in most cases is lacking. Consequently, fertilizer advisory services become dependent upon blanket recommendation approach. Subsequently, it affects yield and profitability. This study is aimed at explaining soil fertility heterogeneity in Wolaita zone, Southern Ethiopia. About 789 soil samples were collected to evaluate soil physical (color, particle size, and bulk density) and chemical properties (pH, OC, N, P, K, Ca, Mg, B, Cu, Fe, Mn, Zn, PBS, and CEC). The laser diffraction method for soil particles and mid-infrared diffused reflectance (MIR) spectral analysis for OC, TN, and CEC determination were employed. Mehlich-III extraction and inductively coupled plasma (ICP) spectrometer measurement were used for the remaining elements. The result based on principal component analysis showed that 52% of the total variations were explained by exchangeable bases, CEC, pH, available P, Cu, B, and particle sizes. Clay texture and acidic soil reaction are dominant. Soil parameters with the following ranges were found at low status: soil OC (0.2–6.9%), total N (0.01–0.7%), available P (0.1–238 mg/kg), S (4–30 mg/kg), B (0.01–6.9 mg/kg), and Cu (0.01–5.0 mg/kg). Besides, low levels of exchangeable Ca, Mg, and K (Mg-induced K deficiency) on 22, 34, and 54% soil samples, respectively, were recorded. The soil contained sufficient Fe, Zn, and Mn. In conclusion, the study aids in developing practical decision for optimum soil management interventions and overcomes lower productivity occurring due to fertilizer use that is not tailored to the local conditions. Overall, continuous cropping, low return of crop residues, and low and/or no fertilizer application might have caused the low status of N, P, K, S, B, and Cu. Therefore, application of inorganic fertilizers specific to the site, lime in acidic soils, and organic fertilizers are recommended to restore the soil fertility and improve crop productivity.

Effects of Organic Nutrient Sources and NPS Fertilizer on the Agronomic and Economic Performance of Haricot Bean (Phaseolus vulgaris L.) in Southern Ethiopia

“…e problems are attributed to continuous cropping of the same land year after year, inadequate replenishment of the lost nutrients, complete residue removal from the field, and soil erosion [6]. In order to curb the soil nutrient depletion, fertilizers, namely, organic, inorganic, or their integration are used as the source of essential plant nutrients.…”

Carbon Stock, Sequestration and Soil Properties among Fields in Smallholder Farms in Southern Ethiopia

“…However, the amount used by each eld was inadequate to replenish the soil quality (Table 1). This may cause the depletion of soil organic matter and essential nutrients to extent limiting crop yield (Eyasu et al, 2019;Fanuel and Kibebew, 2020).…”

“…Particularly, in Wolaita, southern Ethiopia, farming has been taking place in less than a quarter of hectare (WZFEDD, 2012). Like other parts in the country, farming is also entirely rain-fed and characterized by low input and low productivity (Fanuel and Kibebew, 2020). To cope up the adverse effects of climate and secure household food demands, smallholder farmers divided the small size land into different elds and grow annual and perennial crops.…”

Carbon stock, sequestration and soil properties among fields in smallholder farms in southern Ethiopia

“…However, the amount used by each field was inadequate to replenish the soil quality (Table 1). This may cause the depletion of soil organic matter and essential nutrients to extent limiting crop yield (Eyasu et al 2019;Fanuel and Kibebew 2020).…”

“…Particularly, in Wolaita, southern Ethiopia, farming has been taking place in less than a quarter of hectare (WZFEDD 2012). Like other parts in the country, farming is also entirely rain-fed and characterized by low input and low productivity (Fanuel and Kibebew 2020). To cope up the adverse effects of climate and secure household food demands, smallholder farmers divided the small size land into different fields and grow annual and perennial crops.…”