Evaluation of soil physical quality of irrigated agroecosystems in a semi-arid region of North-eastern Brazil

Soil Research ◽  
2012 ◽  
Vol 50 (6) ◽  
pp. 455 ◽  
Author(s):  
V. P. Pereira ◽  
M. E. Ortiz-Escobar ◽  
G. C. Rocha ◽  
R. N. Assis Junior ◽  
T. S. Oliveira

Concern about soil physical quality has grown in recent years, particularly in view of serious problems caused by intensive soil use. We hypothesised that improper soil management in irrigated areas damages the structure of sensitive soils in some regions in North-eastern Brazil. The aim of the study was to evaluate the physical quality of irrigated soils planted with annual and perennial crops, compared with soils under natural vegetation in Ceará State, Brazil. Measurements were made of least limiting water range (LLWR), the S index, and relative density. Undisturbed soil samples were collected at two depths (5–10 and 20–25 cm) in four cultivated areas (banana, guava, pasture, and maize/bean in succession) and two natural vegetation areas (NV1, NV2) adjacent to the cultivated areas. All sites were in the Jaguaribe-Apodi Irrigated District, Limoeiro do Norte, Ceará, Brazil. The LLWR was determined using the water retention curve, soil resistance to penetration, and soil bulk density, which are parameters needed to obtain the upper and lower limits of LLWR. The S index was obtained from the water retention curve. The relative density was obtained from the relationship between bulk density and maximum density obtained from the Proctor test. The S index varied as a function of soil management. The variation in LLWR differed between the studied areas as a function of soil bulk density. The relative densities for NV1 and NV2 were lower than for cultivated areas, showing that intensive soil use has caused compaction. The studied parameters seem to be good indicators of soil physical quality, and it was noticed that soils under cultivation suffer an alteration of their structure relative to soils under natural vegetation.

2010 ◽  
Vol 34 (1) ◽  
pp. 211-2178 ◽  
Author(s):  
Fabiana de Souza Pereira ◽  
Itamar Andrioli ◽  
Amauri Nelson Beutler ◽  
Cinara Xavier de Almeida ◽  
Faber de Souza Pereira

The intensive use of land alters the distribution of the pore size which imparts consequences on the soil physical quality. The Least Limiting Water Range (LLWR) allows for the visualization of the effects of management systems upon either the improvement or the degradation of the soil physical quality. The objective of this study was to evaluate the physical quality of a Red Latosol (Oxisol) submited to cover crops in the period prior to the maize crop in a no-tillage and conventional tillage system, using porosity, soil bulk density and the LLWR as attributes. The treatments were: conventional tillage (CT) and a no-tillage system with the following cover crops: sunn hemp (Crotalaria juncea L.) (NS), pearl millet (Pennisetum americanum (L.) Leeke) (NP) and lablab (Dolichos lablab L.) (NL). The experimental design was randomized blocks in subdivided plots with six replications, with the plots being constituted by the treatments and the subplots by the layers analyzed. The no-tillage systems showed higher total porosity and soil organic matter at the 0-0.5 m layer for the CT. The CT did not differ from the NL or NS in relation to macroporosity. The NP showed the greater porosity, while CT and NS presented lower soil bulk density. No < 10 % airing porosity was found for the treatments evaluated, and value for water content where soil aeration is critical (θPA) was found above estimated water content at field capacity (θFC) for all densities. Critical soil bulk density was of 1.36 and 1.43 Mg m-3 for NP and CT, respectively. The LLWR in the no-tillage systems was limited in the upper part by the θFC, and in the bottom part, by the water content from which soil resistance to penetration is limiting (θPR). By means of LLWR it was observed that the soil presented good physical quality.


2014 ◽  
Vol 38 (2) ◽  
pp. 444-453 ◽  
Author(s):  
Thalita Campos Oliveira ◽  
Laura Fernanda Simões da Silva ◽  
Miguel Cooper

The concept of soil quality is currently the subject of great discussion due to the interaction of soil with the environment (soil-plant-atmosphere) and practices of human intervention. However, concepts of soil quality relate quality to agricultural productivity, but assessment of soil quality in an agronomic context may be different from its assessment in natural areas. The aim of this study was to assess physical quality indices, the S index, soil aeration capacity (ACt/Pt), and water storage capacity (FC/Pt) of the soil from a permanent plot in the Caetetus Ecological Reserve (Galia, São Paulo, Brazil) under a seasonal semideciduous forest and compare them with the reference values for soil physical quality found in the literature. Water retention curves were used for that purpose. The S values found were higher than the proposed limit for soil physical quality (0.035). The A and E horizons showed the highest values because their sandy texture leads to a high slope of the water retention curve. The B horizons showed the lowest S values because their natural density leads to a lower slope of the water retention curve. The values found for ACt/Pt and FC/Pt were higher and lower than the idealized limits. The values obtained from these indices under natural vegetation can provide reference values for soils with similar properties that undergo changes due to anthropic activities. All the indices evaluated were effective in differentiating the effects of soil horizons in the natural hydro-physical functioning of the soils under study.


2011 ◽  
Vol 343 (4) ◽  
pp. 295-301 ◽  
Author(s):  
Glenio Guimarães Santos ◽  
Euzebio Medrado da Silva ◽  
Robélio Leandro Marchão ◽  
Pedro Marques da Silveira ◽  
Ary Bruand ◽  
...  

2018 ◽  
Vol 10 (7) ◽  
pp. 46
Author(s):  
Diego Dos Santos Pereira ◽  
Rafael Montanari ◽  
Christtiane Fernandes Oliveira ◽  
Jean Carlos de Almeida Ramos ◽  
Alan Rodrigo Panosso ◽  
...  

The soil physical quality is a way of evaluating the current condition of forest plantations that is growing in the southeast region of Mato Grosso do Sul State. In this sense, this work aimed to evaluate the impact of the forest plantations on the physical quality of an Oxisol (Haplic Acrustox) in Cerrado. The experiment was conducted in the Experimental area of the Teaching and Research Farm, of the Engineering college of Ilha Solteira (UNESP), located in the city of Selvíria-MS, situated in the conditions of the Brazilian Cerrado. The soil samples were collected at depths of 0.00-0.10; 0.10-0.20; 0.20-0.30 and 0.30-0.40 m in three areas cultivated for 30 years: area (1) Pine forest (Pinus caribaea var. hondurensis); (2) Eucalyptus forest (Eucalyptus camaldulensis); (3) Reforested ciliary forest, being used a completely randomized design, with 25 replications and 3 treatments. The analyzed attributes of the soil was: macroporosity (Ma), microporosity (Mi), total porosity (TP), bulk density (BD), real particle (RP), soil resistance to penetration (PR), gravimetric moisture (GM), volumetric moisture (VM) and sand, silt and clay contents. The three evaluated areas presented macroporosity below the critical limit (0.100 m³ m-³), thereby impairing the root development. The three evaluated areas affected the physical quality of the soil. Being the physical attributes that most influenced in the reduction of the soil physical quality was the bulk density, total porosity, microporosity, macroporosity and soil resistance to penetration.


2014 ◽  
Vol 38 (5) ◽  
pp. 471-479 ◽  
Author(s):  
Raphael Henrique da Silva Siqueira ◽  
Mozart Martins Ferreira ◽  
Elifas Nunes de Alcântara ◽  
Bruno Montoani Silva ◽  
Raphael Comanducci Silva

Weed control in different crops affects the chemical, physical, and biological properties of the soil and consequently its structural quality. The objective of this study was to evaluate, using water retention characteristics and the S index, the physical quality of an Oxisol (Red-Yellow Latosol), subjected to weed control during the cultivation of coffee. The following weed control methods were evaluated: harrowing, brushcutting, residue crushing, manual weeding, post-emergence herbicide application, pre-emergence herbicide application, and maintenance of soil cover with peanut forage, Brachiaria grass, and spontaneous vegetation (no weed treatment). The following properties were determined for physical characterization of the soil: bulk density, total porosity, macroporosity, microporosity, water retention, and the S index. The weed control method significantly affected the physical properties and water retention in the subsurface layer of the Oxisol. Soil bulk density, total porosity, macroporosity, and microporosity were significantly correlated with the S index. According to the S index, the physical quality of the soil was classified as very good for the various weed control methods investigated.


2017 ◽  
Vol 56 (1) ◽  
pp. 45-53 ◽  
Author(s):  
O. Fenton ◽  
S. Vero ◽  
R.P.O. Schulte ◽  
L. O’Sullivan ◽  
G. Bondi ◽  
...  

AbstractHistorically, due to a lack of measured soil physical data, the quality of Irish soils was relatively unknown. Herein, we investigate the physical quality of the national representative profiles of Co. Waterford. To do this, the soil physical quality (SPQ) S-Index, as described by Dexter (2004a,b,c) using the S-theory (which seeks the inflection point of a soil water retention curve [SWRC]), is used. This can be determined using simple (S-Indirect) or complex (S-Direct) soil physical data streams. Both are achievable using existing data for the County Waterford profiles, but until now, the suitability of this S-Index for Irish soils has never been tested. Indirect-S provides a generic characterisation of SPQ for a particular soil horizon, using simplified and modelled information (e.g. texture and SWRC derived from pedo-transfer functions), whereas Direct-S provides more complex site-specific information (e.g. texture and SWRC measured in the laboratory), which relates to properties measured for that exact soil horizon. Results showed a significant correlation between S-Indirect (Si) and S-Direct (Sd). Therefore, the S-Index can be used in Irish soils and presents opportunities for the use of Si at the national scale. Outlier horizons contained >6% organic carbon (OC) and bulk density (Bd) values <1 g/cm3 and were not suitable for Si estimation. In addition, the S-Index did not perform well on excessively drained soils. Overall correlations of Si. with Bd and of Si. with OC% for the dataset were detected. Future work should extend this approach to the national scale dataset in the Irish Soil Information System.


1998 ◽  
Vol 55 (3) ◽  
pp. 498-502 ◽  
Author(s):  
O.O.S. BACCHI ◽  
K. REICHARDT ◽  
J.C.M. OLIVEIRA ◽  
D.R. NIELSEN

The soil water retention curve is fundamental for the hydraulic characterization of a soil and has many applications in agricultural research as well as in practical agriculture. A new procedure for soil moisture and soil bulk density evaluation inside closed pressure chambers through gamma-ray beam attenuation is presented. The proposed procedure presents several advantages in relation to the traditional process: avoids the need of continuous sample manipulation; minimizes the problem of hysteresis; allows a more precise evaluation of soil moisture by taking into account changes of soil bulk density due to swelling or shrinking on addition or removal of water; allows frequent evaluation of soil moisture without the need of opening the pressure chamber; allows a more precise judgement of equilibrium; reduces drastically the time of the determination of the retention curve and allows easy automation of data acquisition by a computer.


2014 ◽  
Vol 38 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Quirijn de Jong van Lier

The S-index was introduced in 2004 in a publication by A.R. Dexter. S was proposed as an indicator of soil physical quality. A critical value delimiting soils with rich and poor physical quality was proposed. At present, Brazil is world leader in citations of Dexter's publication. In this publication the S-theory is mathematically revisited and extended. It is shown that S is mathematically correlated to bulk density and total porosity. As an absolute indicator, the value of S alone has proven to be incapable of predicting soil physical quality. The critical value does not always hold under boundary conditions described in the literature. This is to be expected because S is a static parameter, therefore implicitly unable to describe dynamic processes. As a relative indicator of soil physical quality, the S-index has no additional value over bulk density or total porosity. Therefore, in the opinion of the author, the fact that bulk density or total porosity are much more easily determined than the water retention curve for obtaining S disqualifies S as an advantageous indicator of relative soil physical quality. Among the several equations available for the fitting of water retention curves, the Groenevelt-Grant equation is preferable for use with S since one of its parameters and S are linearly correlated. Since efforts in soil physics research have the purpose of describing dynamic processes, it is the author's opinion that these efforts should shift towards mechanistic soil physics as opposed to the search for empirical correlations like S which, at present, represents far more than its reasonable share of soil physics in Brazil.


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