Eduardo Oliveira de Jesus Santos

Variabilidade e correlação espacial de micronutrientes e matéria orgânica do solo com a produtividade da pimenta-do-reino

Studies on the spatial variation of soil properties associated with the response of crop yields may contribute to a rational application of inputs, enabling economic and environmental gains. The purpose of this work was to evaluate the variability and spatial correlations among soil Fe, Cu, Zn, Mn, and organic matter contents and yield of black pepper grown on a Yellow-Red Latosol. The study was carried out on a black pepper plantation under microsprinkler irrigation, in Sao Mateus, State of Espirito Santo, Brazil. The experimental area was 100 x 120 m (12.000 m2). Soil was collected from under the tree canopies in the 0-0.20 m layer, in a grid with minimum distances of 5 m, totaling 126 soil samples. The black pepper production was estimated by harvesting the three plants nearest to each sample point. All measurable semivariogram properties were satisfactorily described by spherical models with a moderate and strong spatial structure. There was a negative spatial correlation between soil Fe content and yield black pepper and positive spatial correlation among Zn, Mn and organic matter contents and black pepper yield.

Variabilidade espacial de macronutrientes em uma lavoura de café conilon no Norte do Espírito Santo

The soils in the state of Espirito Santo, Brazil (ES) display low natural fertility, which often limits the production of the crops due to the deficiency of some elements. However, they have a high potential for agricultural production when the chemical limitations which are present are overcome. The aim of this study was to describe the spatial variability of the macronutrients calcium (Ca), magnesium (Mg), phosphorus (P) and potassium (K) in a crop of conilon coffee (Coffea canephora Pierre) located in the rural area of the city of Sao Mateus, ES. The experiment was carried out on a crop, planted at a spacing of 1.8 x 1.0 m (5,555 plants ha-1). A rectangular grid of 61.6 x 20.0 m (1,232 m2) was considered, with 60 sampling points, spaced 5.6 m apart between rows and 5.0 m within each crop row. At each point in the sampling grid, soil samples were collected at a depth of 0.00-0.20 m. All the macronutrients under study displayed a strong spatial dependence. The greatest range of spatial dependence was observed for Mg (32.4 m) and the smallest for Ca (8.1 m). Study of the spatial variability of the chemical properties of the soil by geostatistics, using kriging, proved to be an important tool in understanding the spatial distribution of macronutrients in the soil, and may be crucial in aiding the decision making that helps to attend the nutritional requirements of the conilon coffee crop.

PRODUTIVIDADE DO CAPIM TANGOLA (Brachiaria mutica x Brachiaria arrecta) NO OUTONO SOB DIFERENTES NÍVEIS DE ADUBAÇÃO E DESCANSO.

O capim tangola, possui grande importância para a producao de pastagem em locais temporariamente alagados com periodo de estiagem, e um hibrido adaptado a areas alagadas e mais resistente a seca, possui caracteristicas fisiologicas como aerenquimas, raizes adventicias, cloroplastos mais proximos a epiderme e epidermes mais finas, que proporcionam sua adaptacao ao alagamento. Dessa forma, objetivou-se comparar a produtividade do capim tangola em um sistema irrigado, sob diferentes doses de adubacao e frequencia de corte no outono. Utilizou-se neste trabalho um Delineamento Inteiramente Casualizado com cinco tratamentos, que sao os diferentes niveis de adubacao e quatro repeticoes, sendo realizados cortes de 21 e 28 dias, em canteiros especificos, a uma altura de 20 cm simulando o pastejo. Os niveis de adubacao obtiverem diferenca significativa a 1% pelo teste de Tukey sem interacao com a epoca de corte de acordo com o periodo de descanso. As adubacoes nitrogenada e potassica aumentaram a produtividade do capim. Independente da producao de biomassa, a relacao folha:colmo, para todos os tratamentos foi estatisticamente igual, no entanto, houve diferenca no dois periodos de descanso, porem a producao de materia seca aumentou. As adubacoes nitrogenada e potassica, aumentaram a produtividade do capim tangola durante o outono e o periodo de descanso de 28 dias, apresentou maior altura do dossel, maior produtividade e menor relacao folha:colmo e a melhor eficiencia de utilizacao do nitrogenio ocorreu para o periodo de descanso de 28 dias associada a dose de 150 kg N ha-1 ano-1 e 120 kg K ha-1 ano-1.

Effects of tillage systems on physical properties of a cohesive yellow argisol in the northern state of Espírito Santo, Brazil

Tillage systems are a key element of the technology of crop production, both with a view to crop yield and from the perspective of soil conservation and sustainability of the production system. The aim of this paper was to evaluate the effects of five tillage systems on the physical properties of a cohesive Yellow Argisol. The experiment was installed in the field on January 21, 2011 and lasted 260 days, in an area previously used as pasture with Brachiaria grass without liming or fertilization, but irrigated by a low pressure spray system. The treatments, in five replications and in a randomized block design, consisted of: 1) disk plow (twice) + disk harrow + ridge-furrow tillage (raising a ridge along the planting row), 135 days after transplanting (DP + RID); 2) disk plow (twice) + disk harrow (DP no RID); 3) subsoiler (SB); 4) disk plow (twice) + disk harrow + scarification with three shanks along the plant row (DP + SPR); and 5) disk plow (twice) + disk harrow + scarification with three shanks in the total area (DP + STA). In all tillage systems, furrows were mechanically opened for the papaya plants. After the treatments, the mechanical resistance to penetration was determined, followed by soil moisture, mean weight diameter (MWD), geometric mean diameter (GMD), bulk density (BD), macroporosity (Ma), microporosity (Mi), and number of fruits per plant. There were differences in penetration resistance (PR) between treatments. The subsoiler was more effective to decrease RP to a distance of 0.35 m from the plants, perpendicular to the plant row. The scarifier resulted in a lower PR than DP or SB, even at the depth of 0.40 m, and it was more effective at greater distances perpendicular to the plant. All tillage systems induced a PR between 2.0 and 3.0 MPa at the depth with the highest concentration of papaya tree roots (0-0.25 m), improving the physical conditions to this depth. There was no statistical difference among the treatments for BD, Ma, Mi, MWD, and GMD at a depth of 0.20 m. The disk plow changed the physical properties of the soil most intensely to a depth of 0.20 m. The use of scarification, reduced tillage with a forest subsoiler, or ridge-furrow tillage did not improve the physical properties in the rhizosphere. Reduced tillage with a forest subsoiler resulted in a lower number of fruits per plant than all other treatments, which did not differ from each other.

Variabilidade espacial de cálcio, magnésio, fósforo, potássio no solo e produtividade da pimenta-do-reino

The black pepper (Piper nigrum L.) has a social importance and it is mainly cultivated by small farmers, however the relationship between the spatial variability of nutrients in soil and yield of black pepper is little known. Thus, the purpose of this study was to analyse the spatial variability of Ca, Mg, K, P in soil and black pepper yield, cultivated in a distrophic Red-Yellow Latosol. The study was carried out in a black pepper plantation, in Sao Mateus, in the State of Espirito Santo, Brazil. A 3 x 1,8 m spacing in a mesh of 100 x 120 m (total area 12.000 m2), with 126 sampling points was used. Soil samples at depth of 0-0.2 m were collected at each point of the grid, in order to evaluate the soil chemical attributes. The variables presented a moderate and strong spatial dependence structure allowing their mapping by geostatistics techniques. Kriging maps were shown to be important tools for the understanding of spatial variability of soil nutrients, and it may be essential for decision making in the black pepper crop.