Variabilidade espaço-temporal de atributos do solo e da produtividade de arroz irrigado em área sistematizada de terras baixas

Abstract

In a land leveled area five years ago, in Embrapa Clima Temperado, a study was developed to evaluate the effect of land leveling on the yield of irrigated rice and Lotus Corniculatus. To perform this experiment 100 points were delineated and the following soil chemical proprieties were analyzed: PH in water, SMP index, Phosphorus (P), boron (B), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), potential acidity (Al + H), aluminum (Al) concentration and organic matter (OM). In addition, the depth of the cut or fill occasioned by the land leveling process, yield and yield component was evaluated. Principal component analysis was employed to verify the interaction among these variables. Before sowing the Lotus Corniculatus, fertilization for correction of the soil fertility was carried out in varied rates. After the Lotus Corniculatus cultivation the area was planted with rice for two seasons. The effect of the land leveling on the variability of chemical attributes P and K in the soil and the irrigated rice yield over time was evaluated. Data were analyzed using the coefficient of variation. There were no negative effects on the dry matter productivity of the Lotus Corniculatus. The land leveled affected the yield variability of the irrigated rice, however, did not cause damages to the average productivity. Fertilization at varied rates provided an increase in area fertility and reduced heterogeneity in spatial distribution of soil chemical contents.