Abstract

DELGADO, Rodolfo et al. Relationship between some soil physical properties and characteristics of the root system of maize grown in a fluventis haplustoll soil of Maracay, Venezuela. Agronomía Trop. [online]. 2008, vol.58, n.3, pp.245-255. ISSN 0002-192X.

The establishment of a relationship between soil physical properties and the root system of maize, Zea mays L., made it possible to determine soil constraints beforehand. In this work, an evaluation was made of the relationship between radical length, root mass density (RMD), root length density (RLD), mean root diameter (RD), and specific root volume (EspVol and length EspeLen) of maize planted under minimum (MT) and conventional tillage (CT), with some physical soil properties (soil resistance to penetrometer (SR), soil bulk density (SBD), macro- and micro-porosity, soil water content (SW), and soil texture). The soil was a Fluventic Haplustoll of the experimental field of CENIAP­INIA, located in Maracay, Aragua state at 10°17' N and 67° 37´ O, and 460 meters above sea level. Significant differences between MT and CT occurred for soil physical parameters SR and SW in the 20 to 50 cm soil layers, and for the root system properties in RLD and RMD in the 30-40 cm soil layer, and DLR and RD, EspVol, and EspeLen in the 40-50 soil layer, where the lowest amount of mass and root length was found. Combining the data for MT and CT together, it was found that SR was significantly related to all the root system parameters, and the quadratic models explained these relationships. The relationship between RP and EspVol, could be useful to predict soil constraints: the limiting RP, where the EspVol is reduced, was 61.6 kg/cm² (6.04 MPa).

Keywords : Maize; roots; index; resistance to pene­tration; relationships between roots and soil properties.