ABSTRACT To evaluate the performance of different sampling arrangements, this work aimed to study, in a field of Eucalyptus camaldulensis, the variability and spatial dependence of some attributes of plant and soil (LATOSSOLO VERMELHO Distrófico [Typic hapludox]). To collect the soil (water content [WC] and soil mechanical penetration resistance [PR]) and plant data (tree height [TH] and circumference at breast height [CBH]), a sampling arrangement containing 122 points was used in an area of 1.98 ha and three other arrangements, with 84, 48 and 42 points. Except for the CBH, the reduction of points did not expressively affect the parameters of the classical statistics of all other parameters evaluated. Spatially, for TH and WC, the reduction of collection points did not significantly affect the geostatistical parameters, allowing estimating mapping similar to the initial mapping with high correlation coefficients. The WC at 0.10-0.20 m layer could be estimated from 48 samples of the WC at 0-0.10 m layer and 48 samples in the layer of 0.10-0.20 m with a correlation coefficient (r) equal to 0.94 when compared to initial kriging from an arrangement with 122 sample points.

ABSTRACT Soil mechanical scarification (MS) and cover crop growing (CC) are strategies to minimize compaction in the soil surface layer under the no-tillage system (NTS). The objective of this study was to evaluate the effects of soil mechanic scarification on the yield and nutrient accumulation in the shoot dry matter of cover crops, as well as the persistence of crop residues in NTS, implemented 12 years ago in the Cerrado conditions with low altitude. The study was carried out in Selvíria, Mato Grosso do Sul state, Brazil, in the 2012 and 2013 harvest, in a clay soil classified as Oxisol Red epi-eutrophic alic. The experimental design was a randomized block arranged in a 5 X 2 factorial scheme, with four replicates. The treatments were constituted by the combination of four cover crops (Cajanus cajan, Crotalaria juncea, Urochloa ruziziensis and Pennisetum glaucum) and fallow with spontaneous vegetation, with or without MS. Soil MS increases the shoot dry matter yield of P. glaucum, U. ruziziensis and C. cajan in the first crop. The P. glaucum species, independently of soil scarification, provide higher yield and accumulation of macronutrients in the shoot dry matter, besides provide higher persistence of crop residues. The U. ruziziensis and C. cajan, independently of soil scarification, have the potential for accumulation of N, P, K and Ca in the shoot dry matter, although with less persistence of residues on the soil surface.

RESUMEN La escarificación mecánica (EM) del suelo y/o el cultivo de plantas de cobertura (PC) son estrategias para minimizar la com-pactación en la capa superficial del suelo en sistema de saneamiento directo (SPD) consolidado. El trabajo tuvo como objetivo evaluar la influencia de la escarificación mecánica del suelo en la productividad y acumulación de nutrientes de la materia seca de PC, así como la persistencia de residuos de cultivos en SPD implantado hace doce años, en condiciones de baja altitud en el Cerrado. El estudio fue desarrollado en Selvíria, MS, en las cosechas 2012 y 2013, en un oxisol rojo epieutrófico, textura arcillosa. El delineamiento experimental utilizado fue de bloques aleatorios dispuestos en esquema factorial 5x2, con cuatro repeticiones. Los tratamientos fueron constituidos por la combinación de cuatro PC (Cajanus cajan, Crotalaria juncea, Urochloa ruziziensis y Pennisetum glaucum) y barbecho con vegetación espontánea, con y sin EM del suelo. La EM del suelo aumenta la productividad de la materia seca de P. glaucum, U. ruziziensis y C. cajan en la primera cosecha. La especie P. glaucum, independientemente de la escarificación, proporciona mayor productividad y acumulación de macronutrientes en la materia seca, además de mayor persistencia de residuos de cultivos. La U. ruziziensis y C. cajan, independientemente de la escarificación, presentaron potencial de acumulación de N, P, K y Ca en materia seca en el brote, aunque con menor persistencia de los residuos en la superfície del suelo.

Resumo A silvicultura com espécies exóticas desempenha importante papel socioeconômico no Brasil, fornecendo matéria-prima para a produção de madeira, lenha, carvão vegetal, celulose, dentre outros. Nesse sentido, torna-se necessário o aprofundamento do conhecimento sobre as variáveis ambientais que controlam a produtividade do Pinus; em especial, as edáficas. O objetivo do presente trabalho foi avaliar a variabilidade espacial dos atributos químicos de solo e planta em um plantio comercial de Pinus caribaea var. hondurensis. O experimento foi instalado no campus da Faculdade de Engenharia de Ilha Solteira (Unesp), localizado em Selvíria, Estado de Mato Grosso do Sul, Brasil, em um Latossolo Vermelho Distroférrico, textura muito argilosa. Foram analisados os seguintes atributos químicos do solo: fósforo (P), matéria orgânica (MO), potencial hidrogeniônico (pH), potássio (K), cálcio (Ca), magnésio (Mg), acidez potencial (H+Al), alumínio (Al), soma de bases (SB), capacidade de troca catiônica (CTC), saturação por bases (V%), cálcio (CaT), magnésio (MgT) e alumínio (m) na CTC (Capacidade de Troca Catiônica). Todos os atributos de solo e planta apresentaram dependência espacial simples na área do estudo, exceto Altura, Diâmetro a Altura do Peito e acidez potencial na camada de 0,10-0,20 m, evidenciando que o manejo de Pinus pode ser realizado de acordo com site específico nas condições do estudo. O potássio foi o atributo de solo que melhor se correlacionou com a produtividade de Pinus em volume, bem como os melhores indicadores para a estimativa da produtividade.

Abstract Forestry with exotic species plays an important socioeconomic role in Brazil, providing raw material for the production of wood, firewood, charcoal, cellulose, among others. In this sense, it becomes necessary to deepen the knowledge about the environmental variables that control the productivity of Pinus, especially the edaphic ones. The objective of the present work was to evaluate the spatial variability of soil and plant chemical attributes in a commercial plantation of Pinus caribaea var. Hondurensis. The experiment was installed on the campus of the Faculty of Engineering of Ilha Solteira (Unesp), located in Selvíria, state of Mato Grosso do Sul, Brazil, in a RED OXYSOL Dystroferric, very clayey texture. The following soil chemical attributes were analyzed: phosphorus (P), organic matter (OM), hydrogen ionic potential (pH), potassium (K), calcium (Ca), magnesium (Mg), potential acidity (C), base saturation (V%), calcium (CaT), magnesium (MgT) and aluminum (m) in CEC (Cationic Exchange Capacity). All soil and plant attributes presented simple spatial dependence in the studied area, except for height, diameter at breast height and potential acidity in the 0.10-0.20 m layer, evidencing that Pinus management can be performed according to the specific site in the conditions of the study. Potassium was the soil attribute that best correlated with the productivity of Pinus in volume, as well as the best indicators for the estimation of productivity.