A Study of Soil Factors in Relation to Erosion and Land Use on a Nigeria Soil.

An assessment of the effects of erosion on the soil productivity of Agbor area of Delta State, Southern Nigeria was evaluated. The investigation involved three (3) soils (Virgin forest, Arable cropping and Traffic soils) with history of erosion. The aggregate stability, mean weight diameter (MWD) and state aggregation of soil of the area was studied, since these soils properties have direct relationship with soil erodibility. The results reveals that the soil texture was loamy sand. mean weight diameter values ranged from 0.56 mm (Traffic), 0.74 mm (arable cropping) and 1.25 mm (virgin forest). State of aggregation ranged from 12.00 mm (arable cropping), 23.00 mm (traffic) and 43.3 mm (virgin forest). Mean porosity 65.4 mm (traffic soils), 72.1 mm (arable cropping) and 77.0 mm (virgin forest). Mean aggregate stability ranged from 74.4 mm (traffic soils), 25.8 mm (arable cropping) and 48.00 mm (virgin forest). Soil organic matter mean values ranged from 0.08 g/ kg (traffic soils), 1.90 g/ kg (arable cropping) and 2.72 g/ kg (virgin forest), respectively. The results recorded for virgin forest relative to arable cropping and traffic soils in most of the soil properties evaluated is an indi- cation that current land use practices in Agbor area contribute immensely to the accelerated soil degradation observed in the area.

A Study of Soil Factors in Relation to Erosion and Land Use on a Nigeria Soil.

An assessment of the effects of erosion on the soil productivity of Agbor area of Delta State, Southern Nigeria was evaluated. The investigation involved three (3) soils (Virgin forest, Arable cropping and Traffic soils) with history of erosion. The aggregate stability, mean weight diameter (MWD) and state aggregation of soil of the area was studied, since these soils properties have direct relationship with soil erodibility. The results reveals that the soil texture was loamy sand. mean weight diameter values ranged from 0.56 mm (Traffic), 0.74 mm (arable cropping) and 1.25 mm (virgin forest). State of aggregation ranged from 12.00 mm (arable cropping), 23.00 mm (traffic) and 43.3 mm (virgin forest). Mean porosity 65.4 mm (traffic soils), 72.1 mm (arable cropping) and 77.0 mm (virgin forest). Mean aggregate stability ranged from 74.4 mm (traffic soils), 25.8 mm (arable cropping) and 48.00 mm (virgin forest). Soil organic matter mean values ranged from 0.08 g/ kg (traffic soils), 1.90 g/ kg (arable cropping) and 2.72 g/ kg (virgin forest), respectively. The results recorded for virgin forest relative to arable cropping and traffic soils in most of the soil properties evaluated is an indication that current land use practices in Agbor area contribute immensely to the accelerated soil degradation observed in the area.

Accumulation of Soil Carbon and Phosphorus Contents of a Rehabilitated Forest

The world's tropical rainforests are decreasing at an alarming rate as they are converted to agricultural land, pasture, and plantations. Decreasing tropical forests affect global warming. As a result, afforestation progams have been suggested to mitigate this problem. The objective of this study was to determine the carbon and phosphorus accumulation of a rehabilitated forest of different ages. The size of the study area was 47.5 ha. Soil samples were collected from the 0-, 6-, 12-, and 17-year-old rehabilitated forest. Twenty samples were taken randomly with a soil auger at depths of 0–20 and 20–40 cm. The procedures outlined in the Materials and Methods section were used to analyze the soil samples for pH, total C, organic matter, total P, C/P ratio, yield of humic acid (HA), and cation exchange capacity (CEC). The soil pH decreased significantly with increasing age of forest rehabilitation regardless of depth. Age did not affect CEC of the rehabilitated forest. Soil organic matter (SOM), total C, and total P contents increased with age. However, C/P ratio decreased with time at 0–20 cm. Accumulation of HA with time and soil depth was not consistent. The rehabilitated forest has shown signs of being a C and P sink.

Separating Duff and Litter for Improved Mass and Carbon Estimates

Mass and carbon load estimates, such as those from forest soil organic matter (duff and litter), inform forestry decisions. The US Forest Inventory and Analysis (FIA) Program systematically collects data nationwide: a down woody material protocol specifies discrete duff and litter depth measurements, and a soils protocol specifies mass and carbon of duff and litter combined. Sampling duff and litter separately via the soils protocol would increase accuracy of subsequent bulk density calculations and mass and carbon estimates that use them. At 57 locations in North Carolina, Virginia, and West Virginia, we measured depth, mass, and carbon of duff and litter separately. Duff depth divided by total depth varied from 20% to 56%, duff was 1–4 times denser than litter, and the calculated median carbon-to-mass ratio for hardwood duff (0.37) was less than that for litter (0.45). Using FIA depth measurements, we calculated mass from (1) our mean density values, (2) a mass versus depth regression model we developed, and (3) published density values. Model mass calculations were lower than those using our mean densities, possibly because the latter ignore density differences with layer thickness. Our model could provide valuable mass and carbon estimates if fully developed with future FIA data (duff and litter separated).