Physical quality of a yellow latossol under integrated crop-livestock system

Fernando Silva Araújo,Zigomar Menezes De Souza,Allan Charlles Mendes De Sousa,Luiz Fernando Carvalho Leite,Adeodato Ari Cavalcante Salviano

doi:10.1590/s0100-06832010000300013

Abstract

Soil physical quality is essential to global sustainability of agroecosystems, once it is related to processes that are essential to agricultural crop development. This study aimed to evaluate physical attributes of a Yellow Latossol under different management systems in the savanna area in the state of Piaui. This study was developed in Uruçuí southwest of the state of Piauí. Three systems of soil management were studied: an area under conventional tillage (CT) with disk plowi and heavy harrow and soybean crop; an area under no-tillage with soybean-maize rotation and millet as cover crop (NT + M); two areas under Integrated Crop-Livestock System, with five-month pasture grazing and soybean cultivation and then continuous pasture grazing (ICL + S and ICL + P, respectively). Also, an area under Native Forest (NF) was studied. The soil depths studied were 0.00-0.05, 0.05-0.10 and 0.10-0.20 m. Soil bulk density, as well as porosity and stability of soil aggregates were analyzed as physical attributes. Anthropic action has changed the soil physical attributes, in depth, in most systems studied, in comparison to NF. In the 0.00 to 0.05 m depth, ICL + P showed higher soil bulk density value. As to macroporosity, there was no difference between the management systems studied and NF. The management systems studied changed the soil structure, having, as a result, a small proportion of soil in great aggregate classes (MWD). Converting native forest into agricultural production systems changes the soil physical quality. The Integrated Crop-Livestock System did not promote the improvement in soil physical quality.

Highlights

Sustainable use of natural resources, especially soil and water, has been growing as a relevant topic, mainly due to the increase in anthropic activities, considering that maintaining the quality of these resources is essential for the growth and development of plants and sustainability of agricultural systems
Anthropic action has significantly affected (p < 0.05) soil bulk density, leading to an increase in depth, in most studied systems, when it is compared to a native forest (NF) (Table 2)
This behavior probably results from farm machine traffic in this area as well as from an effect of animal trampling that exerts pressure on the soil and dislocates soil particles to the inner porous place, which leads to a reduction in macroporosity and in soil compaction

Summary

Introduction

Sustainable use of natural resources, especially soil and water, has been growing as a relevant topic, mainly due to the increase in anthropic activities, considering that maintaining the quality of these resources is essential for the growth and development of plants and sustainability of agricultural systems. Converting native areas into intensive soil management systems, through of agricultural and cattle raising activities, may change both physical attributes and soil quality, jeopardizing its sustainability. Physical attributes are changed by the pressure exerted on the soil surface, either by farm machines or by animal trampling. Soil compaction can be caused by rain drop impact, by excessive use of farm machinery and agricultural implements as well as by animal trampling. These are some of the main reasons why the productive capacity of agricultural soils has degraded (Albuquerque et al 2001; Lanzanova et al 2007). Evaluation of the consequences of these changes is grounded in the measurement of some soil physical attributes, such as soil density, soil porosity (Lanzanova et al, 2007) and soil aggregate stability (Colonego & Rosolem, 2008)

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Conclusion