Espaçamento do grid e número de subamostras na coleta de solo com agricultura de precisão

Abstract

The objective of the present work was to evaluate the spacing of the sampling grid and number of subsamples in the quality of the soil collection in an area under precision agriculture. The work was carried out in the municipality of Mangueirinha, Southwest of Paraná State, in a field of 21.83 ha of a farmer assisted by the Agriprecisão company. The area was divided into uniform glebas, respecting the management history, soil color and texture variation, soil drainage, vegetation type and previous crop. In April 2016, after harvesting soybean crop 2015/16, soil sampling was performed using different grid spacing and number of subsamples, a) sampling grid of 1 ha and 6 subsamples; B) sampling grid of 2 ha and 6 sub-samples per gleba; C) sampling grid of 2 ha and 12 subsamples. The soil was collected in the 0-10 cm layer, since it is an annual crop under no-tillage system, in the line of the crop. The soil was sampled with quadricycle equipped with soil sampler of the threaded type. Afterwards, the soil samples were sent to the soil laboratory of UTFPR-DV. They were air dried, milled and sieved in a 2.0 mm mesh. Soil samples were characterized when the pH values in H2O, CaCl2 and SMP, and total carbon (C), total phosphorus (P) and total potassium (K) were determined according to the methodologies described in Tedesco et al. (1995). For the soil sampling grid of 2.0 ha the number of subsamples may decrease from 12 to 6. The decrease in the size of the sampling grid from 2.0 to 1.0 ha, associated with a decrease in the number of subsamples of 12 To 6 raised the quality of the evaluation of the heterogeneity of the land, at the same time that it did not increase the work for the execution of the service. To try to achieve better results, it is suggested to sample with a grid of 1 ha and 12 subsamples and compare with the other methods.