ABSTRACT In areas of no tillage system where there is intense traffic of machines and minimal soil mobilization, the periodic monitoring allied on localized soil compaction represent important strategies aiming agricultural sustainability. Thus, the objective of this study was to evaluate the spatial variability of soil resistance to penetration (RP) in no tillage system. Data collection took place in an experimental area of 7.65 ha using a sample grid composed of 40 points. At each point the RP was determined by three replications from which was obtained the mean RP, the maximum RP, and the depth of the maximum RP in the 0-0.40m layer. Deformed samples were randomly collected in the area to determine the water content in the soil (θ). Then the RP data were analyzed using descriptive and geostatistical statistics techniques for spatial variability maps. The RP presents spatial variability detected by means of spherical semivariogram in all soil layers. There was spatial variability in the area with the appearance of intermediate values for RP (2.00-3.00 MPa) due to no ploughing and continuous traffic of agricultural machines. There were greater reaches and critical levels of compaction on the layers 0.10-0.20 and 0.20-0.30 m where there is predominance of the maximum RP.

ABSTRACT Soil resistance to penetration is an indicator of easy measurement which can be used to make scarification / subsoiling recommendations in areas that work with localized management. The objective of this study was to evaluate the spatial variability of soil resistance to penetration (RP) in the area of direct sowing system, and to carry out the recommendation of scarification / subsoiling in a localized way through precision agriculture. The research was conducted in commercial area, in a field of 49.12 ha. The RP collection was with an electronic penetrometer in a sample mesh of 47 points distributed regularly in the area, with georeferenced points. The data were analyzed every 0.10 m being collected up to 0.40 m depth, in addition to obtaining the mean and maximum RP values in the profile (0 – 0.40 m), and the depth value of the maximum RP in the profile. Soil samples were collected randomly in the area to characterize the water content at the time of RP collection. Data were analyzed using descriptive statistics and geostatistics. The resistance to penetration (RP) presents moderate to strong spatial dependence in the evaluated layers. The RP is in most of the area below the critical limits which demonstrates that there is no need to perform a scarification / subsoiling in the total area, only in a localized way.