Farmers’ soil knowledge, fertility management logic and its linkage with scientifically analyzed soil properties in southern Ethiopia

Abstract

Background: Farmers' locally have acquired knowledge from generations of experience and experimentation that fit local conditions. Yet, the scientific approach less used farmers' soil knowledge (FSK) and site-specific soil information. The objectives of this study were to investigate FSK and rationality; to demonstrate how FSK relates to scientifically analyzed soil properties; and to explore the implemented soil management practices and crop performances in selected districts of Wolaita zone, southern Ethiopia. A total of 789 farmers were included, and their fields were evaluated. Data on farmer's soil nomenclature, soil physicochemical property, soil fertility management practices and crop yield performance were recorded and analyzed.Results: Farmers describe and classify their soils using holistic approach. Soil nomenclature and classification indicators are relatively homogeneous over large area. Accordingly, seven soil types common over large area were identified. Mostly, soil types perceived fertile by farmers (e.g., Arrada bita) were found better in measured physicochemical properties than infertile soil types (e.g., Lada bita, Zo' o bita). Simple regression analysis revealed a declining trends of soil properties with a decrease in fertility of farmers soil types such as soil bulk density (r 2 = 0.78), pH (r 2 = 0.53), available phosphorous (r 2 = 0.83), total exchangeable bases (r 2 = 0.71), copper (r 2 = 0.64) and zinc (r 2 = 0.69). Farmers are rational to allocate the scarce fertilizers. They apply more chemical fertilizer when soil type was getting poor in soil fertility (r 2 = 0.61), whereas it was opposite for manure (r 2 = 0.85). Furthermore, crop response and farmers' soil type also demonstrated an observable relationship where yield was declining with a decrease in fertility level of farmers' soil types. Conclusions:Farmers understand within farm soil variability and exploit soil fertility differences of their field. This is supported with noticeable relationship with scientifically analyzed soil properties, fertility management strategy and crop responses. It suggests that FSK is relevant for site-specific soil management. Yet, FSK is deficient to identify yieldlimiting nutrients, implying it has to be complemented with scientific soil knowledge. Additionally, further investigation to systematically link both approaches is also suggested.

Soil fertility assessment and management from the perspective of farmers in four villages of eastern South Africa

“…Such differences can explain why soil testing did not pick up fertility differences perceived by farmers. The reported mismatch is consistent with Gruver and Weil () but contrary to several similar studies that reported good agreement between farmer and laboratory assessments (Berazneva, McBride, Sheahan, & Guerena, ; Laekemariam, Kibret, & Mamo, ; Yageta, Osbahr, Moromoto, & Clark, ; Yeshaneh, ). The differences in farmer‐identified fertility classes in these studies were largely attributed to soil management rather than inherent properties of the soil.…”

“…Similar to Laekemariam et al (2017) and Kome, Enang, and Yerima (2018), there seemed to be a relationship between farmer fertility assessment and farm practices such as crop management, resource allocation and time of planting as well as general cropping systems. Farmers acknowledged the ability of fertile soils to adequately support crop growth and that they require less manure compared to perceived infertile soils.…”

Soil and Irrigation Water Management: Farmer’s Practice, Insight, and Major Constraints in Upper Blue Nile Basin, Ethiopia

“…The farmers' perception and soil lab results showed that farmers' local knowledge is vital, and should be valued and combined with scientific findings to have a better soil type and fertility status information. Farmer's described and classified the soils using locally acquired knowledge from generations of experience that fit local conditions [31]. Orimoloye [32] found that farmer's soil fertility ranking was significantly associated with values of organic carbon and available P gained from lab analysis.…”

Agro‐ecology, resource endowment and indigenous knowledge interactions modulate soil fertility in mixed farming systems in Central and Western Ethiopia

“…Such knowledge transfer across agro-ecological zones may have been responsible for the common farmer perception that red soils are less fertile than black and brown soils. Farmers describe and classify their soils using a holistic approach and use relatively homogeneous soil classification indicators across agro-ecologies (Laekemariam et al, 2017). Accordingly, farmers have been using soil colour, soil texture, soil depth, topography and drainage, as well as crop performance as criteria to categorize their land into fertile and less fertile fields (Belachew & Abera, 2010;Corbeels et al, 2000;Karltun et al, 2013;Yeshaneh, 2015).…”

“…In the low and midlands, a higher variability between fertile and less fertile fields was observed for soil pH and P av . Farmers considered red soils as less fertile and used this as an indicator for soil acidity (soil pH) (Laekemariam et al, 2017). The low P av values might have been a result of P fixation in acidic soils (Agumas et al, 2014).…”