Revista Brasileira de Ciência do Solo
versión On-line ISSN 1806-9657
VIEIRA, Sidney Rosa et al. Spatial variability of leaf nutrient content and soybean yield grown for two years in a rhodic hapludox. Rev. Bras. Ciênc. Solo [online]. 2010, vol.34, n.5, pp.1503-1514. ISSN 1806-9657. http://dx.doi.org/10.1590/S0100-06832010000500003.
The chemical analysis of plant tissue is an efficient method to assess the nutritional status. This study aimed to characterize the spatial variability of plant nutrients and soybean yield in an experimental area (120 x 160 m, totaling 1.92 ha) of a Rhodic Hapludox under no tillage for two years. Soybean leaf and grain yield were sampled at 63 points in a regular 20 m grid. Plant nutrient contents (N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn) were determined analyzing the 3rd leaf from the top, collected from five plants randomly chosen near the sampling points. The crop yield was measured in 5 m2 subplots and expressed in kg ha-1. Data were analyzed using descriptive statistics to assess the measures of central tendency and dispersion. Spatial variability was analyzed using semivariogram parameters and contour maps based on interpolation by ordinary kriging. Spatial dependence was observed for some foliar nutrient contents and crop productivity in a homogeneously fertilized area of about 2 ha. Spatial dependence was not constant over time, which should be taken into account in studies with sequential crops. The spatial dependence of soybean yield increased in the two years studied. Among the nutrients applied annually by fertilization, the formation of a spatial pattern was observed in 1986 and 1988, especially for P.
Palabras clave : foliar diagnosis; geostatistics; no tillage system.