Estimativa da retenção e disponibilidade de água para os solos do Rio Grande do Sul

Abstract

Soil storage capacity and water availability have a direct influence on good plant growth and development. The compaction of the soil and the high concentration of toxic aluminum in the soil make it difficult for the plants to grow, limiting root growth, with less water available. The amount of water stored and available in the soil can be estimated through mathematical models, pedotransfer functions. In this context, this work aimed to estimate the availability and retention of water for the soils of the state of Rio Grande do Sul through existing pedotransfer functions. The pedofunctions used come from the literature, from na article entitled Estimation of water retention and availability in soils of Rio Grande do Sul. To calculate the field capacity, the pedofunction CC 10kPa = 0.506 was used. x clay0.31 (R² = 0.92) and for the calculation of the permanent wilting point, the pedofunction PMP 1500kPa = 0.39 x clay0.51 (R² = 0.85) was used. Field capacity was standardized at 10 kPa and wilting point at 1500 kPa. Based on these data, total soil water storage capacity and soil water availability at different effective soil depths were calculated. Data on soil characteristics come from the Rio Grande do Sul State Soil Recognition Survey. Soils with clay texture tend to have higher water storage capacity. Soil water storage capacity was higher in deeper soils, as was the amount of water available to plants. Soils with depth less than 25cm are not recommended for soybean (Glycine max) and corn (Zea mays) cultivation. Providing good conditions for the effective root growth of plants to exceed 60 cm greatly increases the days when the plant will not suffer from severe water deficit.