Estimativa da produtividade de pastagens de capim Urochloa humidicola (Rendle) Schweick a partir de modelagem agrometeorológica

Abstract

The objective of this study was to evaluate some agronomic characteristics and the performance of the Agroecological Zone Method (MZA) in the estimation of dry matter productivity of two Urochloa humidicola grasslands, in the southern region of the state of Mato Grosso. For the evaluation of pastures and analysis of the model, two field experiments were installed, in pastures formed with humid grass, in a randomized block design with 24 treatments and 3 repetitions. The locations of the experiments were Santo Antônio de Leverger, MT and Vila de São Vicente da Serra. The evaluations took place simultaneously, with a difference of one day between the experiments, and resulted from the samplings carried out at fixed intervals of 14 days, in the period of 12 months. During this period, the variables of the humid grass were evaluated: canopy height (H), specific leaf area (AFE), leaf area index (IAF) and dry matter productivity; and the physical and physical-hydric characteristics of the soil: texture, soil water storage (ARM), soil water retention curve (CRA), saturated soil hydraulic conductivity (K0), microporosity (Mi), macroporosity (Ma), total porosity (PT) and overall density (dg). The meteorological variables were obtained at the stations of the locality of the experiments. The morphophysiological and productive characteristics of Urochloa humidicola grass vary by location. Water availability in the soil is the main determinant of this variation. The best relationship between these characteristics and the water availability of the soil depends on the location and depends on the relief conditions and the attributes of the respective soils. The MZA model presents satisfactory performance to estimate the productivity of humid grass.