Zigomar Menezes de Souza

Sistemas de colheita e manejo da palhada de cana-de-açúcar

The use of sugarcane harvesting without residue burning is a common harvesting management in Brazil. The objective of this work was to evaluate the effect of harvest systems and management of sugarcane with and without trash incorporation and of burned sugarcane on soil physical attributes as on production of stems in a Red Yellow Latosol (Typic Hapludox). The treatments can be described as sugarcane (Saccharum officinarum) with burning and manual cutting; sugarcane without burning and automated cutting, with incorporation of chopped residue down to 0.30 m; sugarcane without burning and automated cutting, without incorporation of chopped residue. The particle size distribution, soil organic matter, aggregate stability, bulk density and soil porosity in 0.0-0.1, 0.1-0.2 and 0.2-0.3 m depths were determined as well as soil resistance to penetration and soil moisture in 0.0-0.1, 0.1-0.2, 0.2-0.3 and 0.3-0.4 m depths. The systems sugarcane without burning and sugarcane with residue incorporation revealed the highest stalk production and higher values of organic matter, aggregate stability, macroporosity, water content and smaller values of soil resistance to penetration and bulk density of soil, compared to sugarcane system without incorporation of residue and burned sugarcane.

Forma da paisagem como critério para otimização amostral de latossolos sob cultivo de cana-de-açúcar

Abstract – The number of sampling points is essential to establish an evaluation program of the spatial variabilityof soil atribute. The objective of this work was to use the form of landscape as auxiliary criterion in the optimizationof the outline sample for the estimate of chemical attributes of oxisol, in a area under sugarcane cultivation. It waspossible to choose a continuous area with two landforms: concave, that occur in higher positions of the area, andlinear, comprising steep, stocking leans and inferior leans. A 50x50 m spacing in a mesh of 300x3.000 m (total area94 ha), with 421 sampling points were used. Soil sample in depths 0.0–0.2 m and 0.6–0.8 m were collected, in eachpoint of the grid, in order to evaluate the soil chemical attributes. In the concave landform, larger space variabilitywas observed for the chemical attributes of the soil. The application of the program Sanos 0.1 in the sampling grid(concave landform and linear landform) allowed to observe that the landform concave in both depths presentslarger space variability of the chemical attributes than the linear landform.Index terms: soil sampling, spatial variability, geostatistics, relationship soil-relief.

Variabilidade espacial de atributos físicos de um Latossolo Vermelho sob cultivo de cana-de-açúcar

O uso intensivo dos Latossolos no nordeste do Estado de Sao Paulo com a cana-de-acucar, com preparo superficial excessivo e queima dos residuos, modifica significativamente as propriedades fisicas do solo. Este trabalho teve como objetivo avaliar a variabilidade espacial de atributos fisicos de um Latossolo Vermelho eutroferrico sob cultivo de cana-de-acucar, atraves da geoestatistica. Os solos foram amostrados nos pontos de cruzamento de uma malha, com intervalos regulares de 10 m, nas profundidades de 0 - 0,2; 0,2 - 0,4 e 0,4 - 0,6 m, totalizando 100 pontos; em cada amostra foram determinadas porosidade total, macroporosidade, microporosidade e densidade do solo. O coeficiente de variacao indicou variabilidade baixa para porosidade total nas profundidades 0,2 - 0,4 e 0,4 - 0,6 m, microporosidade na profundidade de 0,2 - 0,4 m e densidade do solo em todas as profundidades estudadas, e media para microporosidade nas profundidades de 0 - 0,2 e 0,4 - 0,6 m e porosidade total na profundidade de 0 - 0,2 m, enquanto a macroporosidade apresentou variacao alta. Os maiores alcances foram observados nas profundidades de 0,2 - 0,4 m e 0,4 - 0,6 m para todos os atributos estudados. Os altos valores para a densidade do solo, sobretudo na profundidade de 0,2 - 0,4 m, promoveram reducao da porosidade total, microporosidade em particular, na macroporosidade, indicando uma compactacao nesta camada. Pequenas variacoes nas formas do relevo condicionam variabilidade diferenciada para os atribultos fisicos do solo.

Retenção de água em dois tipos de latossolos sob diferentes usos

For every type of soil, the water retention curve is specific and depends on several soil features. This study was carried out to evaluate the influence of soil attributes on water retention in Red Latosol (Haplustox) and Red Latosol (Eutrustox) under different management and use systems. The use systems were: cotton, sugar-cane and woods. The granulometric composition, bulk density, organic matter, Fe2O3 and Al2O3 contents, as well as the water retention curve were determined for soil samples from different depths (0-10, 10-20, 20-30 and 30-40 cm). Organic matter did not demonstrate effective participation in water retention, while the attribute bulk density had the greatest positive correlation with water retention. Eutrustox soil presented greater water retention in all tensions and, in relation to Haplustox, the same capacity of available water (CAW).

Atributos físicos de Latossolos adubados durante cinco anos com biossólido

Universidade Estadual Paulista Faculdade de Ciencias Agrarias e Veterinarias Departamento de Tecnologia

Small relief shape variations influence spatial variability of soil chemical attributes

Soils with small variations in relief and under the same management system present differentiated spatial variabilities of their attributes. This variability is a function of soil position in the landscape, even if the relief has little expression. The aim of this work was to investigate the effects of relief shape and depth on spatial variability of soil chemical attributes in a Typic Hapludox cultivated with sugar cane at two landscape compartments. Soil samples were collected in the intercrossing points of a grid, in the traffic line, at 0-0.2 m and 0.6-0.8 m depths, comprising a set of 100 georeferenced points. The spatial variabilities of pH, P, K, Ca, Mg, cation exchange capacity and base saturation were quantified. Small relief shape variations lead to differentiated variability in soil chemical attributes as indicated by the dependence on pedoform found for chemical attributes at both 0-0.2 m and 0.6-0.8 m depths. Because of the higher variability, it is advisable to collect large number of samples in areas with concave and convex shapes. Combining relief shapes and geostatistics allows the determination of areas with different spatial variability for soil chemical attributes.

Movimento de água e resistência à penetração em um Latossolo Vermelho distrófico de cerrado, sob diferentes usos e manejos

Na Fazenda Experimental da Faculdade de Engenharia de Ilha Solteira - UNESP, no Estado do Mato Grosso do Sul, conduziu-se um estudo com o objetivo de se avaliar as modificacoes do movimento de agua de um Latossolo Vermelho distrofico sob vegetacao de cerrado, para diferentes condicoes de uso e manejo do solo. O delineamento experimental foi inteiramente casualizado, com 6 tratamentos e 10 repeticoes, constando dos seguintes usos e manejos: plantio direto com culturas anuais; preparo convencional com culturas anuais; cultivo minimo com culturas anuais; vegetacao natural (cerrado); area com pastagem e area com cultura de seringueira. Foram avaliados o movimento da agua no solo atraves da infiltracao na superficie, condutividade hidraulica do solo saturado e resistencia do solo a penetracao, nas profundidades de 0-0,10; 0,10-0,20 e 0,20-0,40 m. O uso e o manejo do solo alteraram o movimento da agua do solo e sua resistencia a penetracao. O cultivo minimo revelou-se como o sistema de manejo com melhores resultados, mostrando maior capacidade de infiltracao de agua no solo, condutividade hidraulica do solo saturado e menor resistencia do solo a penetracao, quando comparado ao sistema de vegetacao natural. Dentre os sistemas de usos e manejos estudados, os sistemas com seringueira e pastagem apresentaram menor capacidade de infiltracao da agua no solo e maior resistencia do solo a penetracao.

Variabilidade espacial da textura de um latossolo vermelho eutroférrico sob cultivo de cana-de-açúcar

Regional studies where geostatistic is applied for describing landscape models have shown that, even in places previously considered homogenous, different spatial dependencies have been found and these had been related to crop productivity. In order to analyze the physical properties spatial variability models of an eutrudox Red Latosol, a regular grid containing 306 points spaced at separation distances of 50 meters was installed in southern Brazil. Soil samples were collected at 0-0.2 m and 0.6-0.8 m in order to determine clay, silt, sand total, sand thick, sand medium, sand fine and sand very fine contents. Data were submitted to descriptive statistics, geostatistic and in sequence to kriging analyzes. The coefficient of variation of studied properties was low for clay and, medium for silt, sand total, sand medium, sand fine and sand very fine and, high for sand thick. All the spatial variability models had moderate variability dependence, with higher ranges for 0-0.2 m of depth. The results showed that the considered homogeneous characteristics of oxisols submitted to the same soil management is not so evident and spatial variability of texture attributes can be distinguished from each other.

Propriedades químicas de um latossolo vermelho distrófico de cerrado sob diferentes usos e manejos

Na fazenda experimental da Faculdade de Engenharia de Ilha Solteira (UNESP), no estado do Mato Grosso do Sul, foi realizado um estudo com o objetivo de avaliar as modificacoes de propriedades quimicas de um Latossolo Vermelho distrofico sob vegetacao de cerrado, para diferentes condicoes de uso e manejo da terra. O delineamento experimental foi o inteiramente casualizado, com seis tratamentos e 10 repeticoes, constando dos seguintes usos e manejos: plantio direto com culturas anuais; preparo convencional com culturas anuais; cultivo minimo com culturas anuais; vegetacao natural (cerrado); area com pastagem e area com cultura de seringueira. Foram analisadas as seguintes propriedades quimicas: calcio, magnesio, potassio e aluminio trocaveis, fosforo extraivel, pH em CaCl2, materia orgânica, soma de bases (S) e CTC efetiva, nas profundidades de 0,0-0,1; 0,1-0,2 e 0,2-0,4 m. Os sistemas plantio direto e cultivo minimo levaram a acumulos significativos de materia orgânica, fosforo, potassio, magnesio e calcio no solo. Foram verificadas, nesses sistemas, elevacao do pH, maior CTC efetiva, soma de bases e diminuicao no teor de aluminio, em relacao aos demais sistemas. Os sistemas pastagem e seringueira apresentaram reducoes nos teores de materia orgânica, fosforo, potassio, magnesio, calcio, diminuicao do pH, menor CTC efetiva, soma de bases e aumento do teor de aluminio, quando comparados a vegetacao natural. Os sistemas plantio direto e cultivo minimo apresentaram melhores condicoes de qualidade ao solo, pois, alem da melhoria nas condicoes quimicas do solo, a materia orgânica manteve-se em niveis similares aos do sistema natural.

Variabilidade espacial de fatores de erosão em Latossolo Vermelho eutroférrico sob cultivo de cana-de-açúcar

The objective of this work was to evaluate the spatial variability of soil erosion factors on a Dark Red Oxisol under sugarcane conventional tillage. Soil samples were collected in 206 points, in a depth of 0.0-0.2 m, located in a 50 m regular grid for obtaining the soil texture and organic matter content. The local erosion factors were determined: erosivity (R), erodibility (K), relief (LS), soil erosion (A), natural potential of erosion (PNE), erosion risk (RE) and erosion expectation (EE). Geostatistical analysis was performed to measure and model the spatial variability of soil erosion factors. The soil variability was moderate with K, A, and PNE while the soil variability was higher with LS, RE, and EE. K, A, and PNE exhibited moderate spatial dependence, but spatial dependence of LS, RE and EE was strong. Kriging maps were presented for understanding of soil erosion factors distribution patterns within the landscape.