Estimation and evaluation of dynamic properties as indicators of changes on soil structure in sugarcane fields of Sao Paulo State - Brazil

Abstract The indiscriminate management and use of soils without moisture control has changed the structure of it due to the increment of the traffic by agricultural machines through the years, causing in consequence, a soil compaction and yield reduction in the areas of intensive traffic. The purpose of this work was to estimate and to evaluate the performance of preconsolidation pressure of the soil and shear stress as indicators of changes on soil structure in fields cropped with sugarcane, as well as the impact of management processes in an Eutrorthox soil structure located in Sao Paulo State. The experimental field was located in Piracicaba's rural area (Sao Paulo State, Brazil) and has been cropped with sugarcane, in the second harvest cycle. The soil was classified by EMBRAPA [EMBRAPA, 1999. Centro Nacional de Pesquisa de Solos. Sistema Brasileiro de Classificacao de Solos, Embrapa, Brasilia, 412 pp.] as an Eutrorthox. Undisturbed samples were collected and georeferenced in a grid of 60 m × 60 m from two depths: 0–0.10 m (superficial layer – SL) and in the layer of greatest mechanical resistance (LGMR), previously identified by cone index (CI). The investigated variables were pressure preconsolidation ( σ p ), apparent cohesion ( c ) and internal friction angle ( ϕ ). The conclusions from the results were that the SLSC was predicted satisfactorily from σ p as a function of soil moisture; thus, decisions about machinery size and loading (contact pressures) can be taken. Apparent cohesion ( c ), internal friction angle ( ϕ ) and the Coulomb equation were significantly altered by traffic intensity. The σ p , c and ϕ maps were shown to be important tools to localize and visualize soil compaction and mechanical resistance zones. They constitute a valuable resource to evaluate the traffic impact in areas cropped with sugarcane in State of Sao Paulo, Brazil.

[1]  K. K. Barnes.  Compaction of agricultural soils , 1971 .

[2]  F. J. Pierce,et al.  A simple procedure for estimating preconsolidation pressure from soil compression curves , 1995 .

[3]  K. Terzaghi,et al.  Soil mechanics in engineering practice , 1948 .

[4]  P. Servadio,et al.  Effects on some clay soil qualities following the passage of rubber-tracked and wheeled tractors in central italy , 2001 .

[5]  Daniel Hillel,et al.  Applications of soil physics , 1980 .

[6]  Benjamin J. Radford,et al.  Changes in the properties of a Vertisol and responses of wheat after compaction with harvester traffic , 2000 .

[7]  P. Ayers.  Moisture and Density Effects on Soil Shear Strength Parameters for Coarse Grained Soils , 1987 .

[8]  Dr. Ir. Adrianus Jozef Koolen,et al.  Agricultural Soil Mechanics , 1983, Advanced Series in Agricultural Sciences.

[9]  P. Schjønning,et al.  Non-inversion tillage effects on soil mechanical properties of a humid sandy loam , 2001 .

[10]  Influência do preparo inicial sobre a estrutura do solo quando da adoção do sistema plantio direto, avaliada por meio da pressão de preconsolidação , 2003 .

[11]  A. Scott,et al.  A Cluster Analysis Method for Grouping Means in the Analysis of Variance , 1974 .

[12]  A. Klute.  Methods of soil analysis. Part 1. Physical and mineralogical methods. , 1988 .

[13]  T. Lambe.  Soil testing for engineers. , 1951 .

[14]  G. W. Snedecor.  Statistical Methods , 1964 .

[15]  A Kezdi,et al.  SOIL PHYSICS - SELECTED TOPICS - DEVELOPMENTS IN GEOTECHNICAL ENGINEERING - 25 , 1979 .

[16]  G. Matheron.  Principles of geostatistics , 1963 .

[17]  A. W. Warrick,et al.  13 – Spatial Variability of Soil Physical Properties in the Field , 1980 .

[18]  J. V. Stafford,et al.  THE FRICTIONAL CHARACTERISTICS OF STEEL SLIDING ON SOIL , 1977 .

[19]  M. F. O'sullivan,et al.  Soil strength and crop emergence in direct drilled and ploughed cereal seedbeds in seven field experiments , 1982 .