SPATIAL VARIABILITY OF LOSSES AND SOIL MECHANICAL RESISTANCE TO PENETRATION IN MECHANIZED PEANUT DIGGING

Abstract

Mechanized peanut harvesting is of great importance in the crop production process but there are considerable losses, especially in the digging operation. The objective of this study was therefore to measure the spatial variability of peanut losses and soil mechanical resistance to penetration (RP) in the mechanized digging operation using two displacement speeds. The study was performed in the northern region of São Paulo State. Treatments consisted of two speeds (V1 = 3.5 km h-1 and V2 = 4.7 km h-1) and ten replications using a completely randomized design (DIC). After the digging the RP measurements were obtained using an electronic penetrometer positioned across peanut lines, taking measurements at every 0.01 m of depth to a maximum of 0.30 m deep, and at every 0.15 m in width to a total of 1.80 m. At the same points losses from digging were determined and classified as visible (PVA), invisible (PIA) and total losses (PTA). Speed of the tractor-digger did not influence the peanut losses evaluated or the RP. Soil mobilization occurred up to 0.13 m in depth and the level across the active parts of the digger was uneven. Correlations were observed between PVA and PIA, and between PTA and RP, but the determination coefficients (R²) were less than 25%.