The mechanical penetration resistance of a soil strongly influences plant development since the root growth as well as the crop yield change inversely proportional to its value. The bean grain yield (GY) and the penetration resistance (PR) in a Dystrophic Red Latosol (Rhodic Ustox) located at the Experimental Station of the Faculdade de Engenharia/UNESP in Ilha Solteira county, São Paulo State, Brazil (22 º 23 ' latitude S; 51 º 27 ' longitude W), were analyzed in the crop year 2001/2002. The main objective was to work out guidelines related to the increase of the crop yield in question by studying the spatial and linear correlation between GY and PR. A geostatistical grid to collect soil and plant data was installed in a 5 x 5 m and a 2.5 x 2.5 m spacing. One hundred and twenty sample points were arranged across an area of 1,875 m². The linear correlation between GY and PR was practically zero since it presented correlation coefficients (r) below 0.20 in function of the studied soil layers. The geostatistical analysis presented a good spatial dependence structure when analyzed for GY as well as PR. However, the joint spatial analysis of the attributes was inconsistent. Thus, with the increasing mechanical resistance to penetration in a particular soil region there was sometimes an increase and sometimes a reduction of the grain yield.
cone index; grain yield; spatial variability; geostatistics
