Quantifying annual soil and nutrient lost by rill erosion in continuously used semiarid farmlands, North Ethiopia

Abstract

The loss of soil from land surfaces by erosion is widespread and reduces the productivity of agricultural lands. Concurrently, due to increasing human population, agricultural land expansion and exploitation, soil erosion and nutrient loss are the major environmental problems in Ethiopia. This study was conducted to estimate annual losses of soil, soil nutrients and carbon due to rill erosion. The entire watershed was classified into 12 land mapping units (LMUs). Consequently, the cropland was delineated to estimate soil and nutrient losses. Dimensions of the rills were measured at different parts of the landscape, and rill volume of rill erosions was assessed in the field. Disturbed representative composite soil samples were taken from each LMU to estimate the main soil nutrients, and each soil nutrient was estimated using different methods. The result revealed that the amount of soil lost through rill erosion was found to be 3.17 t ha -1 year -1 . The average annual nutrient loss by the rill erosion was 41.4 kg ha -1 soil organic matter content, 2.4 kg ha -1 total N, 0.02 kg ha -1 available P and 0.3 kg ha -1 exchangeable K. The annual estimated cost of the soil nutrient lost (total N and available P) due to rill erosion was found to be 1341 USD. This cost would be used to replace the total N and available P nutrients lost through the addition of mineral fertilizers. Water erosion in the form of rill erosion was severely affecting soil fertility management and crop production in the study watershed. Hence, effective integrated watershed management interventions and farmland managements could combat soil erosion.

Cause and cost of onsite nutrient loss replacement in the highlands of Ethiopia and implication of Soil and Water Conservation measures

“…For example, Grum, et al [16] obtained 90.6 kg ha -1 annual average soil losses due to sheet erosion with average annual nutrient losses estimated as 36.4kg ha -1 total N, 25.9 kg ha -1 available P in Gule Sub-Watershed, North Ethiopia. Similarly, Erkossa, et al [1] obtained 5.7 t ha −1 yr −1 annual average soil losses due to sheet erosion in Dapo catchment in the Blue Nile basin with average annual nutrient losses estimated as 14.0 kg/ha total N, 6.8 kg/ha available P. Berhane, et al [68] also observed that 3170 kg ha −1 yr −1 annual average soil loss due to rill erosion with average annual OM and total N nutrient losses estimated as 41.4 kg ha −1 and 2.4 kg ha −1 respectively in Ruba Gered watershed, North Ethiopia. This implies that the nutrient loss, especially the N and P losses, from the catchment were strongly related to the sediment loss, emphases that where there is high soil loss, there is also high onsite nutrient loss from the system.…”

“…Various studies reported that soil erosion in the form of water resulting in the loss of valuable plant nutrients (NPK and SOM) with the eroded soil [1,16,18,[66][67][68]. For instance, in the past Haileslassie [17] reported that the contribution of soil erosion to NPK loss in teff land use was 70%, 80%, and 63 % respectively.…”

Diagnóstico do uso e conservação do solo em região de reforma agrária no semiárido

“…Porém, isso pode contribuir para o processo de erosão acontecer de forma lenta e gradual, pouco perceptível aos agricultores, mas que causa, em longo prazo, grandes prejuízos ambientais (LEMMA et al, 2017).…”

Modelling spatial and temporal soil organic carbon dynamics under climate and land management change scenarios, northern Ethiopia

“…Soil is the largest organic carbon pool of terrestrial ecosystems, which strongly interacts with atmospheric composition, climate and land management (Yigini & Panagos, 2016). Notably, SOC affects soil functions such as habitat, biological diversity, soil fertility, crop production potential, erosion prevention and water storage (Lema et al, 2019; Lema, Kebede, Mesfin, Fitiwy, & Abraha, 2016; Lemma, Kebede, Mesfin, & Fitiwy, 2017; Mesfin et al, 2018a; Mesfin, Taye, & Hailemariam, 2018b; Tadesse, Mesfin, Tesfay, & Abay, 2016). The SOC from previous and current soil management remains an important source of atmospheric carbon dioxide (CO 2 ), with SOC stocks continuing to decline for a long time after the start of cultivation.…”