Cultivares de abobrinhas sob diferentes condições de cultivo na região de Sinop-MT

Abstract

The vegetables during their growth and development are considered to be sensitive to the adverse conditions of the environment mainly in relation to the availability of water and solar radiation which directly influences the temperature of the air and soil. The objective was to evaluate the agronomic performance, potential evapotranspiration and to obtain the cultivation coefficients (Kc) for cultivars of "Italian" zucchini (Cucurbita pepo) and "Brazilian Girl" (Cucurbita moschata), submitted to three cultivation conditions (Millet straw, crotalaria and uncovered), in a dystrophic Red-Yellow Latosol, in the municipality of Sinop-MT. The experiment was carried out in two stages, in which the precultures were sown: crotalaria and millet which were cut before flowering, then crushed, dried and distributed in the growing area with density 2.5 kg m -2 , Already in the second stage the pits were opened, the irrigation system was installed and planting of the seedlings of the cultivars: Italian squash and Brazilian Girl took place. In the area was installed four batteries consisting of three tensiometers that remained at (10, 20 and 30 cm) in each treatment to assist in irrigation management. The evaluations to obtain agronomic performance consisted of nondestructive growth analyzes: number and linear dimensions of leaves, branch length and plant height, stem diameter, number of male, female flowers and fruit growth and fruit harvest It was determined the length, fresh mass, diameter of the bulb and the peduncle of the fruit. At the end of the cycle, the analysis of destructive growth was carried out at the end of the productive cycle by obtaining the parameters: dry mass of leaves, stem, root and area Leaf on five random plants per treatment. In the evaluation of the volume of water in the soil, the tensiometer readings were performed using the digital tensiometer in the evening period, and the values were inserted in the Van Genuchten equation that after adjusting allowed to verify the storage difference between two days and to determine the evapotranspiration Of the crop and calculate the irrigation blade. By regression analysis of the parameters: height, plant length, stem diameter, number of leaves and leaf area, an adjustment of the equation of the second-degree polynomial type was found. Analyzing the number of total flowers found for each sex in the treatments, as well as the number of fruits along the cycle shows a tendency to grow at the beginning of the measurements and until a maximum point decreasing subsequently. It was verified in the analysis of destructive growth for most of the evaluated variables, that the use of the soil cover with the millet grass allowed to obtain the highest average values, therefore better development of the plant in both cultivars. The absence of soil cover caused the dry mass percentage of the root system to be higher in this treatment. The evapotranspiration of the crop and the cultivation coefficient showed no difference between the treatments tested, whereas the efficiency in the water use presented a difference with 7,84, 4,80 and 2,87 in the cv. Italian and 6,64, 2,77 and 0,58 kg m-3 in the Brazilian Girl by the us method2. It was concluded that the use of soil cover in both cultivars influenced the agronomic performance of the zucchini plus did not influence the crop evapotranspiration nor the crop coefficient.