Assessment of Variability in the Quality of an Acrisol under Different Land Use Systems in Ghana

Abstract

Three land use types (natural fallow, Leucaena leucocephala woodlot and cultivated plots) on a Ferric Acrisol in a semi-arid tropical zone of Ghana were compared to assess their effects on variability in selected soil properties and plant biomass accumulation. Organic carbon accumulation in the representative natural fallow profile was 22.7 g/kg, followed by 16.5 g/kg for the Leucaena woodlot and lastly 11.8 g/kg for the cultivated site. The mean bulk density of the natural fallow, Leucaena woodlot and cultivated sites were from 1.36 Mg/m<sup>3</sup>, 0.92 Mg/m<sup>3</sup> and 1.33 Mg/m<sup>3</sup> with corresponding range in mean weight diameter of 0.5 mm - 1.2 mm, 0.6 mm - 1.2 mm and 1.0 mm - 1.2 mm, respectively. The lower bulk density observed for the woodlot corresponds to increased total porosity, aeration, and root proliferation due to the stronger and extensive rooting system. Significant differences (P < 0.05) in bulk density, mean weight diameter (MWD), clay content, organic carbon and total nitrogen existed among the land use types. Variability in pH and bulk density of the surface soils was less than 15%, in the three land use types. Generally, clay content and exchangeable Na recorded the highest variability (<u>></u>36%). For the surface soils, exchangeable Na was very variable in the natural fallow. Exchangeable Na, Ca and K and total nitrogen were very variable in the Leucaena woodlot and the cultivated sites. Variability in clay content was very high in the cultivated soils only. The order cultivated land > Leucaena woodlot > natural fallow was noted for properties with high variability (CV <u>></u> 36%). Plant biomass accumulation was 1834 kg/ha (natural fallow) and 830 kg/ha (Leucaena woodlot) indicating that natural fallows do not only maintain soil quality but they also decrease variability in soil properties which is desirable for soil productivity and quality

Spatial variability of uncultivated soils in derived savanna

“…Whereas the variability was low for bulk density, total porosity and 60-cm moisture content, it was high for macroporosity and very high for K s . Similar results for bulk density have been severally reported across various landscapes in the West-African savanna (Abu and Malgwi, 2011;Folorunso et al, 1988;Ghartey et al, 2012;Idowu et al, 2003;Okon and Babalola, 2006) and the United States (Adhikari et al, 2012). The soil moisture content has also been reported to exhibit low spatial variability (Ogunkunle, 1993).…”

“…For the acid Ultisols that abound in the tropics, variability is due mostly to inherent factors of soil genesis and inherited factors of land use (Dobermann et al, 1995). The West African savanna is one region with limited data on soil variability across different land uses of the soil resources (Idowu et al, 2003), including the more widespread Ultisols (Ghartey et al, 2012). Okon and Babalola (2006) noted that soil variability could be induced even in a uniform field by erosion and runoff deposition.…”

Spatial assessment of soil quality indicators under different agricultural land uses

“…This could be as a result of the leaf litterswhich contributed to the formation of organic matter. As seen in the surface maps, high values of organic carbon, K and available P were spotted in some areas of the cocoa plantation site and these could have contributed to the higher values of MBC and MBN.Soil organic matter rejuvenates degraded soils and increases biomass production [31] and differences in the quantity and quality of substrate inputs via varying litter and root types and associated nutrient specificity can be crucial drivers to influence the soil microbial biomass [32,33].This study suggests that mono-cropping with cocoa has a better soil quality than the other agricultural land uses.…”

Land Rehabilitation on Post-fire Area with Different Types of Soil in Gunung Mas Regency, Central Kalimantan

“…Bulk density merupakan petunjuk dari kepadatan tanah. Tanah dengan kandungan klei yang tinggi cenderung memiliki bulk density yang tinggi (Garthey et al 2012). Hal ini dapat dilihat pada jenis tanah Acrisol yang memiliki nilai bulk density yang lebih besar (1,39 g/cm 3 ) dibandingkan dengan jenis tanah Podsol (1,27 g/cm 3 ).…”