Soil dry aggregate stability and wind erodible fraction in a semiarid environment of Argentina

COLAZO, J.C.; BUSCHIAZZO, D. E.

GEODERMA

ELSEVIER SCIENCE BV

Año: 2010

0016-7061

The size and stability of soil aggregates are primary factors that affect the soil susceptibility to wind erosion. 2121 Relationships among several soil properties and both the wind erodible fraction (EF) and the dry aggregate 2222 stability (DAS) can allow the development of simple mathematical models which can be useful to quantify 2323 soil resistance against wind erosion. Considering this we studied 28 cultivated (CULT) and uncultivated 2424 (UNCULT) soils of the central semiarid region of Argentina with variable clay, organic carbon (OC), CaCO3, 253, 25 and amorphous Al (Alo) and Fe (Feo) oxides contents. Results showed that cultivation increased 2626 EF and reduced DAS in medium textured soils (silt+clay between 215 and 500 g kg−1), but not in sandy 27−1), but not in sandy 27 (silt+clayb215 g kg−1) nor in fine textured soils (silt+clayN500 g kg−1). Cultivation of medium textured 28b215 g kg−1) nor in fine textured soils (silt+clayN500 g kg−1). Cultivation of medium textured 28 soils produced the weakening of soil structure through the loss of OC and the breaking down of aggregates. 2929 These soils did not contain enough inorganic cementing agents like clay or Alo, which may avoid the 3030 deterioration of soil structure. In fine textured soils the formation of large and resistant clods by tillage of 31fine textured soils the formation of large and resistant clods by tillage of 31 cultivated soils produced more similar EF and DAS than in uncultivated conditions. It seems that the lack of 3232 EF and DAS differentiation between management systems in sandy soils were produced by their low 3333 contents of organic and inorganic cementing agents, even in uncultivated conditions. EF and DAS were 3434 related to OC, Alo and clay contents in a logarithmic or an exponentially way. Such relationships allowed the 3535 identification of critical OC, Alo and clay contents below which the resistance of the soil against wind erosion 36fication of critical OC, Alo and clay contents below which the resistance of the soil against wind erosion 36 is reduced drastically. DAS showed critical values at OC contents of 10 g kg−1 in CULT and 29 g kg−1 in 37−1 in CULT and 29 g kg−1 in 37 UNCULT and clay contents of 100 g kg−1 in UNCULT. Alo critical contents were 1000 g kg−1 for EF and DAS in 38−1 in UNCULT. Alo critical contents were 1000 g kg−1 for EF and DAS in 38 both managements. There were no effects of Feo and CaCO3 on EF and DAS in the studied soils. We concluded 393 on EF and DAS in the studied soils. We concluded 39 that the control of wind erosion requires different technologies according to soil texture: management 4040 practices which tend to increase the organic matter contents can be successful for the development of large 4141 and resistant aggregates which are effective in controlling wind erosion in medium textured soils. The large 4242 and stable clods formed by tillage in cultivated fine textured soils are effective in controlling wind erosion. In 43fine textured soils are effective in controlling wind erosion. In 43 sandy soils, probably management practices which tend to increase the amount of organic cementing agents 4444 of the soil will not be effective in controlling wind erosion. Such goal must be achieved through the increase 4545 of coverage of the soil surface with plant residues or canopy.