ABSTRACT Sandy-textured soils are naturally more vulnerable to the erosion process and their exploitation, although possible, is often performed inappropriately, favoring its degradation. In this context, this study aimed to classify the rainfall erosivity in a region of sandy soils to identify critical situations of soil and water loss and also correlate it with rainfall data to assess whether there is temporal dependence of this variable using geostatistical techniques. The potential for alternative and sustainable production systems to be used in regions with sandy soils was also analyzed. Historical data of precipitation in the study region were analyzed to determine the average monthly and annual erosivity indices, which were classified and its temporal dependence was assessed by applying geostatistics. NDVI data from satellite images were used to investigate the soil cover pattern in different production systems. Geostatistics was adequate for the analysis of rainfall erosivity, which showed moderate to strong temporal dependence. It was classified between strong and very strong and was highly dependent on precipitation, with events of higher erosion potential between October and March in the studied region. The vicious circle of degradation of sandy soils, such as those of the Bolsão region of Mato Grosso do Sul, Brazil, can be modified by adopting alternative and sustainable production systems that value the maximization of soil cover. Sandytextured Sandy textured exploitation possible inappropriately context techniques indices geostatistics Sul Brazil

Na maioria das vezes, o manejo da irrigação tem sido realizado sem critérios e ainda são escassos os estudos em relação ao desenvolvimento de eucalipto irrigado em campo. O objetivo deste trabalho foi avaliar equações de volume de madeira com base no diâmetro do caule de dois híbridos de eucalipto em desenvolvimento inicial, sob irrigação e sem irrigação. O experimento foi instalado em Aquidauana, MS, no período de abril de 2011 a março de 2012, com os híbridos de eucalipto Eucalyptus grandis x Eucalyptus camaldulensis (Grancam) and Eucalyptus urophylla x Eucalyptus grandis (Urograndis), irrigados por gotejamento, microaspersão e também testemunha sem irrigação. As avaliações foram realizadas durante o primeiro ano de desenvolvimento da cultura quando foram testados cinco modelos matemáticos para estimativa de volume de madeira (Berkhout; Koperzik e Gehrhardt; Exponencial; Brenac; Hohenald e Krenn). Os melhores modelos de estimativa do volume de madeira de plantas jovens são os de Brenac, Exponencial e Holhenald e Krenn. A equação de Brenac apresenta maior precisão para estimar o volume de madeira em função do diâmetro a 5 cm de altura do solo com precisão acima de 99% para as plantas até 12 meses de idade, independente do uso da irrigação.

Irrigation management has mostly been performed without criteria and, studies in relation to field-irrigated eucalyptus development are scarce. The aim of this study was to evaluate wood volume equations based on stem (trunk) diameter of two eucalyptus hybrids in initial development, with and without irrigation. The experiment was set up in Aquidauana, State of Mato Grosso do Sul, Brazil, from April, 2011 to March, 2012, with the eucalyptus hybrids, Eucalyptus grandis x Eucalyptus camaldulensis (Grancam) and Eucalyptus urophylla x Eucalyptus grandis (Urograndis). Evaluations were performed during the first year of crop development in which five mathematical models were tested for estimation of wood volume (Berkhout; Koperzik & Gehrhardt; Exponential; Brenac; Hohenald & Krenn). The best models for estimation of wood volume of young plants are Brenac, Exponential and Hohenald & Krenn. The Brenac equation shows highest precision for estimating wood volume as a function of diameter at 5 cm height from the ground, with precision greater than 99% for plants up to 12 months of age, regardless of the use of irrigation.

O eucalipto oferece diversas vantagens em comparação a outras espécies florestais, e utilizando a irrigação localizada pode aumentar a produtividade e diminuir o tempo de produção. Objetivou-se pelo presente estudo avaliar dois híbridos de eucalipto (Grancam e Urograndis), sem irrigação e irrigados por gotejamento e microaspersão aos 90; 120; 150 e 180 dias após transplante (DAT). O experimento foi instalado na área experimental de irrigação da Universidade Estadual de Mato Grosso do Sul, no município de Aquidauana-MS. O delineamento experimental foi o de blocos casualizados, em parcelas subdivididas, com quatro blocos e duas replicações dentro de cada bloco, sendo que as parcelas foram compostas pelos tratamentos de irrigação (gotejamento, microaspersão e sequeiro), e as subparcelas, pelos híbridos (Grancam e Urograndis). Foram avaliadas a altura de plantas, o diâmetro do caule e da copa, a área basal do caule, a relação entre altura e diâmetro do caule, a relação entre altura e diâmetro da copa e o volume do caule. Os dados foram submetidos à análise de variância e comparadas pelo teste de Tukey, no nível de 5% de probabilidade. Os sistemas de irrigação por gotejamento e microaspersão propiciam maior altura de plantas, diâmetro do caule, diâmetro da copa, área basal do caule e volume de caule.

The eucalyptus offers several advantages compared to other forestry species and, by using the irrigation can increase productivity and decrease production time. The objective of the present study was to evaluate two hybrid eucalyptus (Grancam and Urograndis), no irrigation, dripping and micro sprinkler irrigated at 90, 120, 150 and 180 days after transplanting (DAT). The experiment was conducted at the experimental irrigation area in the State University of Mato Grosso do Sul, in the municipality of Aquidauna - State of MS, Brazil. The experimental design was randomized blocks, split plot with four blocks and two replications within each block, and the plots were composed by irrigation treatments (dripping, micro sprinkler irrigate and dry) and the subplots the hybrids (Grancam and Urograndis).The total area of the experiment had 3 hectares, where each plot consisted of 1 ha. It was evaluated plant height, stem diameter and canopy, stem basal area, the relationship between height and stem diameter, the relationship between height and canopy diameter and stem volume. Data were subjected to analysis of variance and compared by Tukey test at 5% probability. Irrigation systems and dripping sprinkle provide greater plant height, stem diameter, canopy diameter, stem basal area and stem volume.