Bruno César Gurski

Ajuste de modelos de produção água-cultura para cana-soca

Sugarcane (Saccharum spp.) is one of the main products in the Brazilian agribusiness. In the Paraná State, sugarcane occupies an area of 665,000 ha, with an annual production of about 50 million tons. The Paranavaí region accounts for 20 % of this production, and the planted area is increasing fast in this region (Paraná 2015). Agriculture is the economic activity that has a higher dependence on weather conditions, which are responsible for the oscillations of agricultural seasons (Souza 2014). Environmental factors directly affect plant growth and development. However, the relations between climatic parameters and agricultural production are quite complex. The influence of climate on sugarcane is remarkable because it is a semiperennial crop, grown under different environmental conditions, causing production variations over the years (Silva et al. 2008). ABSTRACT RESUMO

ATRIBUTOS FÍSICOS E BALANÇO HÍDRICO DO SOLO COM FLORESTA OMBRÓFILA MISTA, EM LATOSSOLO VERMELHO-AMARELO, EM TELÊMACO BORBA - PR

The objective of this study was to characterize the soil physical and hydric attributes and quantify, in one year, the water balance components, carried out for Native Ombrophylous Forest, in an OXISOL, sandy texture, in Telemaco Borba - PR state. The experiment was held at Monte Alegre Farm, which belongs to the company Klabin Florestal, the area was under native forest in an advanced state of regeneration. The following physical and hydric attributes were characterized: bulk density, saturated hydraulic conductivity, soil water retention curve, aeration porosity and total available water ( TAW ). The undisturbed samples were collected in a trench, in five depths. The disturbed samples were collected weekly, in eight different points inside the experiment area, in five depths. The values of soil moisture and internal precipitation were collected and registered throughout the year. The soil water storage was calculated using the trapezoidal rule. The internal drainage and capillary rise were estimated by using the Darcy-Buckingham equation. The values of the bulk density, micro, macro and total porosity of the soil are classified in the range considered adequate for soils with sandy texture. The soil presented a high hydraulic conductivity, which is a characteristic of well drained soils. In average, the storage did not reach the permanent wilting point throughout the year. The average deep drainage was bigger throughout the months with more precipitation, the value being an average of 94.9 mm year –1 . The average value of the real evapotranspiration was 1355.9 mm year - 1 , an average of 3.7 mm day - 1 .