Effects of Land Clearing and Subsequent Management on Soil Physical Properties

Abstract

Large scale, mechanized land clearing is common in the humid tropics even though little attention has been given to defining and solving soil problems that may be created. The purpose of this study was to evaluate various combinations of land clearing method, burning of vegetation, post clearing tillage, and soil management on soil physical properties of a forested Ultisol in the Amazon basin. Land clearing methods used were (i) slash, (ii) bulldozer clearing with a straight blade, and (iii) bulldozer clearing with a shear blade. Specific effects associated with clearing were mechanization, bulldozer blade type, burning, disking, and chiseling. Post clearing soil management systems isolated effects of bedding, liming, and fertilization. Soil physical properties were measured before clearing and 14, 29, and 98 weeks after clearing. Compaction increased bulk density (ρb) of the 0‐ to 15‐cm depth for all clearing methods, but ρb of the 15‐ to 25‐ depth increased by 0.1 Mg m−3 only for the bulldozer cleared treatments. Soil texture of the 0‐ to 15‐cm depth was not altered by land clearing. Gravimetric water content at soil matric potentials < −2 kPa was greatest for the straight blade cleared soil. The infiltration rate 14 weeks after clearing decreased 37, 96, and 90% for soil cleared by slash, straight blade, and shear blade, respectively, as compared to initial conditions. Chisel plowing and disking the newly cleared land increased the infiltration rate compared with straight blade without chiseling. Detrimental changes in soil physical properties caused by clearing were minimized when post clearing management practices of bedding, fertilization, and liming were adopted.

Rehabilitation of degraded tropical forest ecosystems: workshop proceedings, 2-4 November 1999, Bogor, Indonesia

“…This insignificance may be due to higher coefficients of variation found for the bulk density. A similar result was reported by Alegre et al (1986) and Craul (1994). Organic matter is well known to affect the fertility of soils through its influence on many other properties such as water holding capacity, soil structure and nutrient availability.…”

Deforestation and land-use effects on soil degradation and rehabilitation in western Nigeria. I. Soil physical and hydrological properties

“…An important consideration among several factors affecting agricultural sustainability of land converted from rainforest to arable or pastoral land use is adverse changes in soil properties that influence the soil's quality and productivity. Deforestation and intensive agricultural land use can lead to land degradation, with drastic adverse changes in soil properties such as an increase in bulk density, a decrease in aggregation and aggregate size distribution, a reduction in available water-holding capacity, a decrease in macroporosity and infiltration capacity (La1 and Cummings, 1979;Alegre, et al, 1986), and an increase in susceptibility to erosion (Lal, 1976). These effects are exacerbated by a reduction in the activity and species diversity of soil fauna, a decrease in the quantity and quality of soil organic matter content, and a possible reduction in the formation of organicmineral complexes, etc.…”

Site-specific soil hydraulic quality index to describe the essential conditions for the optimum soil water regime

“…This parameter can explain 23% of the total variance (Table 6), and was either negatively or positively correlated with at least five attributes (Table 7). Pore distribution could be an important property to determine soil hydraulic quality, especially in terms of soil water flow (Lin et al 1996) and soil water content (Alegre et al 1986). Soils with more fine pores (B7.5 mm in diameter) have more effective water retention, while a relatively better arrangement of fine ( B7.5 mm in diameter) and coarse pores (150 mm in diameter) enables faster water flow.…”

“…Measurement of these attributes directly gives an indication of the hydraulic quality of soils. Other soil physical and chemical properties, such as soil texture, soil structure, and organic matter are also used to predict the hydraulic behavior of soils (Alegre et al 1986;Ghuman et al 1991;Trojan and Linden 1998;Clothier 2001;Youngs 2001;Carminati et al 2006;Pidwirny 2006;Zhuang et al 2008). It is, however, essential to identify how these parameters affect the soil moisture regime, soil fertility and the overall changes in soil quality (Mausbach and Seybold 1998;Andrews et al 2002).…”