Quantification of soil and nutrient loss due to yam harvesting: A case study in two local government areas in Benue state, Nigeria.

Abstract

Soil loss due to crop harvesting is a recognized erosion process which has significantly contributed to soil degradation. Despite its significance, soil loss due to crop harvesting has been given little attention in Benue state and Nigeria at large. This is evident in the paucity of information on soil loss due to crop harvesting in Nigeria. Therefore a field experiment was conducted to quantify soil and nutrient loss due to yam harvesting in two local government areas (Kwande and Ushongo) of Benue state and to identify factors which could contribute to soil loss in these areas. Data collected on soil loss were subjected to t-test at α = 0.05. Average crop yield in Kwande was 18.9 t ha-1 and 16.3 t ha-1 in Ushongo with corresponding soil loss of 3.26 t ha-1 harvest-1 and 1.97 t ha-1 harvest-1 respectively. Higher soil loss observed in Kwande compared to Ushongo can be attributed to higher crop yield and clay content of the soil. Crop yield, clay content and soil organic matter correlated positively with soil loss in Kwande (r = 0.75, r = 0.58, r = 0.65) while in addition to crop yield and clay content sand correlated negatively with soil loss in Ushongo (r = 0.77, r = 0.60, r = -0.60). Soil nutrient losses for nitrogen, phosphorus and potassium were significantly higher in Kwande compared to Ushongo by 2.71, 2.67 and 2.02 times respectively. The findings suggest that soil loss in these areas could degrade the land within a short time, especially where mono-cropping of yam is practiced. Farmers are therefore advised to hand-rub yam tubers while harvesting on the field and practice crop rotation.

Influence of fertilizer application on soil and nutrient loss during carrot harvesting

“…Dada et al (2016) also observed that soil bulk density in addition to soil texture has significant effects on soil loss. Similarly, Samson and Ityavnongo (2021) in an experiment, reported a significant relationship between soil texture and soil loss due to yam harvesting. However, in our study, soil properties such as bulk density and soil texture had no relationship with soil loss.…”

“…Other studies have reported soil properties such as bulk density, soil structure, and texture to be critical factors controlling soil loss (Ruysschaert et al, 2007b;Dada et al, 2016;Oshunsanya et al, 2018;Parlak et al, 2021 andItyavnongo, 2021). For example, Oshunsanya et al (2018) reported soil bulk density negatively related to soil loss due to yam harvesting.…”

“…Also, increase in crop yield could result in an increase in soil loss because total soil loss is a product of crop yield. Several researchers have reported crop yield significantly increases soil loss (Isabirye et al, 2007;Parlak et al, 2016;Oshunsanya et al, 2019;Ityavnongo, 2021 andOshunsanya et al, 2022a). For example, Oshunsanya et al (2019) in a study on soil loss due to yam harvesting, reported fertilizer application increased yam yield and root hair and consequently, soil loss.…”

“…Another likely reason for the higher soil nutrient loss noticed with fertilization is the higher carrot root yield. Previous research has shown root yield to be a contributing factor to soil nutrient loss (Isabirye et al, 2007;Oshunsanya, 2016a;Oshunsanya, 2016b;Parlak et al, 2018 andItyavnongo, 2021). Higher root yield could provide a larger root size area for soil adherence which will also account for the increased nutrient loss (Oshunsanya et al, 2019).…”

“…SLCH is described as loose soil, soil clods, and rock fragments that stick to crops and are exported and transported with harvested crops (Ruysschaert et al, 2004;Ruysschaert et al, 2006a;Oshunsanya, 2016b;Parlak et al, 2018;Panagos et al, 2019 andItyavnongo, 2021). Such crop includes carrot (Daucus carota L.), cassava (Manihot esculenta C.), garlic (Allium sativum L.), peanut (Arachis hypogaea L.), potato (Solanum tuberosum L.), sweet potato (Ipomoea batatas L.) and yam (Dioscorea rotundata).…”