Crescimento de erva-mate consorciada com plantas de cobertura em argissolo

Abstract

Yerba mate has great socioeconomic and cultural importance, mainly in southern Brazil, Paraguay and Argentina. However, due to the multiplicity of uses and importance that this forest species has gained in recent years, its consumption has conquered new frontiers. In order to increase the productivity of yerba mate plantations in order to meet the demand and the sustainability of natural resources, it is important to adopt conservation practices, such as the use of soil cover plants. the objective of the study was to evaluate the growth of yerba mate implanted in soil with sandy surface texture, intercropped with soil cover plants. The experiment was implanted in november 2014, in a randomized block design, with four blocks and five treatments: perennial soybean (SP), forage peanut (AF), mowed spontaneous vegetation (VR) black oat + vetch (in the fall / winter period) and cowpea (In the spring / summer period) (S1) and black oat + forage turnip (in the fall / winter period) and cowpea (in the spring / summer period) (S2). Soil samples with preserved structure were collected with metal rings at depths 0-5, 5-10, 10-20 and 20-40 cm of the soil, to determine soil density, pore distribution, hydraulic conductivity and soil permeability on the air. The distribution of the size of the stable aggregates in water was evaluated at depths 0-5 and 5-10 cm. Non-preserved soil samples were also collected at depths 0-5, 5-10, 10-20 and 20-40 cm for the analysis of chemical properties, particle size and soil particle density. Soil temperature and moisture were obtained through an automated data collection system. The temperature was measured using a system composed of multiplexers, dataloggers and thermocouples inserted in the center at depths 0-5, 5-10 and 10-20 cm. Soil moisture was measured by a system composed of TDR, multiplexers, dataloggers and probes inserted in the center at depths 0-5, 5-10, 10-20 and 20-40 cm. The growth of the yerba mate was evaluated by measuring the total height, diameter at ten centimeters height of the plant, leaf area and chlorophyll fluorescence. Two years after the implantation of the experiment, no significant difference was found between the treatments for pore distribution, density, air permeability, hydraulic conductivity and soil aggregation. However, differences were verified for soil chemical properties, with higher potential acidity and lower magnesium, potassium and calcium contents in AF. In the AF, the highest values of moisture and the lowest values of soil temperature were also found, in most of the evaluated days. At the age of five months of the trees, in the VR was observed the highest growth of the plants. However, at two years of age, growth was higher in AF. The forage peanut is a soil cover plant best suited for use in weed plantings, because it provides edaphic conditions more favorable to the growth of yerba mate, for the edaphoclimatic conditions of the study.